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FAQs on Tapwater Filtration: Reverse Osmosis, Deionized, Distilled Water System Selection

Related FAQs: RO/DI & Distilled Water 1, RO/DI & Distilled Water 2, RO/DI & Distilled Water 3, RO/DI & Distilled Water 4, RO/DI & Distilled Water 5, RO/DI & Distilled Water 6, RO/DI & Distilled Water 7, Rationale, For Commercial/Large Output, RO Water Storage, RO Water TreatmentMaintenance/Repair, Deionizing Source Water Filtration, Kati-Ani DI Units, Kold-Steril Units, Water Make-up, Nitrates

Related Articles: Water Purification Using Reverse Osmosis, Reverse Osmosis, A Multipurpose Tool By Mark E. Evans, Water ChangesWater QualitySynthetic or Natural Seawater, Nitrates

We use a "cheapy" warehouse store unit... and change the carbon pre-filters often (every couple of thousand gallons)... the RO membranes about every ten pre-filter changes... Bob Fenner

Comments about Distilled Water? (RMF, you might want to comment on your comments here'¦)<<RMF>> 10/5/10
Hi Crew,
<Hello,>
This is my first email to WWM. I've learned quite a lot while browsing your site the last couple months, and I want to thank you for providing your services.
<Cool.>
I just stumbled on a comment by Neale that I would like some clarification on if possible.
On the page: http://wetwebmedia.com/FWSubWebIndex/crayfshfaq2.htm
Neale mentions in the first FAQ on the page that: "No! Don't use distilled water for either fish or crayfish! This is VERY, VERY BAD for them. Use dechlorinated tap water, from the drinking water tap, if you have a domestic water softener."
Exactly why would Distilled water be �VERY, VERY BAD� for fish or crayfish? It's pure water (H2O)? It's more pure than what comes out of the RO systems that most experts recommend for aquarium source water. It's certainly better than the water that comes out of the faucets in most municipalities. Personally I'm just curious how it would be bad as I have been using only distilled water in my aquariums for many months now, and have noticed no side effects from it. Usually the reason people try to pass is that Distilled water does not have some of the minerals and such found in tap water, which seems sort of ignorant. I'd personally prefer to add my own minerals to the water so I know exactly what is in it. Not sure if you guys have browsed any municipal tap water reports in the last 10 years or so, but the �allowable� levels of some very toxic chemicals is a bit absurd. Things like Arsenic, Uranium, and many other extremely toxic compounds have �acceptable levels� and are actually found in some municipal water sources. There can also be elements like Copper and other heavy metals present in tap water (even dechlorinated or passed through an RO system) which can be very toxic to many invertebrates, even in trace amounts. Then there are the biological contaminants that even chlorine/Chloramine don't get rid of.
<You misunderstand my point there. I have nothing against distilled water. But distilled water ALONE is unsuitable for fishkeeping; you need to add something to provide minerals including those that buffer against pH changes. In that question the fishkeeper appeared to be doing water changes with just distilled water. As for the quality of tap water, I think you're being a bit sensitive to some of the scare stories put about by the press. Chemicals like arsenic and uranium are all around us and in the minuscule amounts found in nature do no harm. Provided your tap water meets WHO standards, it's safe to drink. Might not taste like Perrier, but it's a heck of a lot better than the water about a billion people on this planet have to live with, in their cases often having to walk miles each day just to carry some water home. We in the West tend to be a bit prissy about stuff like this, without realising how incredibly lucky we are to have safe, clean drinking water on tap. And in almost all cases, tap water is more than adequate for fishkeeping, provided you choose fish species suitable to your local water chemistry.>
After seeing Neale's comment I read a little bit on the water quality FAQs on the WWM site and most of the crew seems to be touting the use of RO/DI systems, while bashing distilled water. I'm just honestly curious why. Distilled water is about the purest water you will find outside of a Laboratory. Most labs and hospitals actually have distiller units onsite. You can't beat 0 TDS every time. An RO system might be able to hit 0 TDS when you put a new filter in, but the longer that filter is in use, the worse the water quality gets. Does WWM have a RO/DI sponsor or something? The only real gray area between RO/DI and Distilled is cost. Distilled costs some money for electricity to produce it. RO costs some money on replacing filters and membranes. If you have a back-flush system you are wasting water, and if you don't you are replacing filters more often. In the end I'd think they would cancel each other out on cost. RO is certainly better than Tap water (just about anything is) but it can't hold up compared to the consistent purity of Distilled. And if cost really is the only issue, then why bash it as a product with comments like its �VERY, VERY BAD�?
<The problem with distilled water is that it's expensive to buy. <<and make>>An RO or DI water filter at home will generally work out much more economical in the long run.>
Bob Fenner seems to think its good stuff, except for the cost of it. Some of his comments from various responses concerning Distilled Water: "Hmm, well, on exposure to the air, gasses will/do enter distilled water... but it's not economical to use for aquarium purposes'¦", "For topping off distilled is ideal... not necessary for water changes... but can be used, definitely", "It is okay... just expensive... and impractical insomuch as you've got to go get it and lug it around... R.O. or Deionized (made at home) would be more than fine"
<Indeed, as I said.><<And my comments are made concerning SALT water, synthetic making, and evaporation make-up>>
As I am typing this, I'm searching for comments on WWM about distilled water. Some comments from the WWM Crew:
Steven Pro begin_of_the_skype_highlighting     end_of_the_skype_highlighting "Distilled water is not good for fish tanks. There is too much of a risk of metal contamination. If you want to use purified water, try RO or DI. Please see here http://www.wetwebmedia.com/rofaq2.htm for more information."
Exactly what is �metal contamination�? Why would distilled water be more prone to it than any other type of water?
<I have no idea what Mr. Pro is talking about here. You'll have to ask him.>
"Awfully expensive and heavy to carry home. You might want to take a look at purchasing your own RO unit to make your own purified water source. Besides, RO water is better than distilled." Exactly how is RO water better than distilled? Seriously, it sounds like Steven works for an RO filter company, or is just plain misinformed.
Ryan: Would an ordinary household type water distiller produce water of a good enough quality to use for top off and salt mix? "Certainly better than tap water. Be sure to use a dechlorinator, and prepare the water properly. http://wetwebmedia.com/water4maruse.htm"
Why would a dechlorinator be needed on Distilled water? Does Ryan know what distilled means, and the purity of the water a distiller produces?
<Not 100% sure what the deal is here either. You'll have to ask Ryan.>
Also, you said "certainly better than tap water". Does this mean it is still not as good as RO water? "Yes, RO water would be ideal"
Another case of stating that RO water is somehow higher quality than Distilled: Neale "No! Don't use distilled water for either fish or crayfish! This is VERY, VERY BAD for them. Use dechlorinated tap water, from the drinking water tap, if you have a domestic water softener."
And here its gone from being not as cost effective, not even just an �inferior� product, but Neale actually implies that it is somehow harmful to use it. How is it harmful?
<Distilled, RO, DI or plain rainwater used to fill an aquarium -- if you don't add any buffering salts -- will create extremely soft water prone to rapid pH drops. Such conditions are very unhealthy for most fish and invertebrates. There are some organisms adapted to such environments, but most tropical fish should not be kept in plain, pure water. Even if you use RO water, you still need to add something, such as a salt mix, to raise the hardness and carbonate hardness a bit.>
I am also involved in Hydroponic gardening, and have had similar conversations around water quality in those circles. That is what got me started using Distilled water in my home in the first place. I have done quite a lot of extensive research into it. From what I have found, most of the �negative� comments about Distilled water originate from RO companies trying to bash the competition.
<Not the issue here. WWM doesn't sell anything save advertising, and to the best of my knowledge there are few if any advertisements from RO companies! So that's not the issue here at all.><<Mmm, to my memory we've never had a 'water filter' sponsor>>
Others are just recycling the same bad information they read somewhere else and are passing it on as a fact. I'm not going to bash RO units. They are certainly much better than straight tap water in most circumstances.
<Actually, that's not true. In "most" circumstances, the best situation is for casual fishkeepers to use unsoftened tap water, and then to choose fish species adapted to their local water chemistry. Marine aquarists may well benefit from using RO water, but freshwater aquarists will generally fine their life easier and cheaper if they use tap water. They can do water changes without having to filter and store water, and they can do water changes as large and as often as they want without worrying about the cost. Plus, if you have fish that like your local water chemistry, issues with pH and hardness don't exist.>
I also agree that buying Distilled water from a grocery store is far from economical. RO units are cheaper than distillers on initial cost, but I believe that cost is offset by membrane replacements over time.
<Indeed. I happen to use rainwater, which is both cheaper and far, FAR "greener" in terms of environmental impact. On the flip side, rain isn't reliable everywhere in the world -- though here in England it is!>
However, for those that have the desire to try distilled water, those curious about it, or those that are thinking of purchasing a distiller for their home, they shouldn't have to read comments trashing it like the ones I've seen from the supposed experts on this forum.
<I think you're being a bit hard on Steve, Ryan, Bob and myself here. At least, I can't explain Steve and Ryan's comments, so you'll have to write to them yourself (they aren't at WWM any more) and find out their own thoughts on this issue. But both Bob and myself aren't arguing that distilled water is bad, but rather than it is expensive and, in freshwater fishkeeping, unsafe if you don't add something to it to raise carbonate and general hardness. In marine fishkeeping you're adding salt mix anyway, so this isn't an issue, but in freshwater fishkeeping if you keep your fish at 0 degrees dH and 0 degrees KH, you'll find they don't do well for long, and the pH will plummet between water changes. I'd suggest that you go back to what Bob and I have written, and read them *in context*, and I think you'll see more clearly what we're getting at.>
Thanks for your time,
-Chris Shelton
<Cheers, Neale.><<Chris, do Neale and I's statements make sense to you? In freshwater environments, there are always some solids (and liquids, gasses) present, and necessary to maintain water quality (e.g. pH, Alkalinity, mineral content...) as well as sustain life. In saltwater aquarium use, distilled can be used to make up synthetic salt mixes and to "top off" systems that have lost mostly "just water"... Distilled water of high purity though, compared with RO, DI or RO/DI is much more money, particularly if home-made. BobF>>
Re: More Re: Comments about Distilled Water? (RMF, you might want to comment on your comments here'¦)<<>>   10/6/10

Hi Guys,
<Hello again Chris,>
I think you misunderstood my comment about testing the water hardness. The water coming out of the distiller is indeed 0 gH/kH. 0 TDS, PH 6.
<And as Bob stated, this *will* rise to 7 given a bit of aeration and time.>
I was saying that when I test the water in the aquariums (those that I do not add Liquid Calcium to), the tests of the aquarium water usually show in the 80-100 range.
<Well, that's coming from somewhere. If you have 80 mg/l CaCO3 in your aquarium, but you're adding distilled water, then there's calcium carbonate getting in there somehow. If not from the water, then calcareous media in the tank, e.g., coral sand. But it's getting in there somehow.><<Yes, from where?>>
I was assuming it was PPM but I think you may be right and it is mg/l. Are they the same thing?
<For our purposes, ppm may well be approximately the same as mg/l.><<Are equivalents>>
Info on the net isn't very clear about that. I accidently wrote dH instead of GH in my previous reply. The test kit doesn't measure degrees of hardness, but I think it would be somewhere in the 8-9 degrees range?
<One degree carbonate hardness, i.e., KH, is 17.8 mg/l of calcium carbonate. General hardness is measured in degrees dH, the dH standing for Deutsche Haerte, or "German hardness" and is strictly measured in calcium oxide, but for historical reasons people usually give an equivalence in calcium carbonate. But do please understand that these are not the same thing at all. Carbonate hardness affects pH, general hardness almost completely doesn't.>
I'm not really positive where that hardness is coming from.
<Nor am I.>
As mentioned I am using only distilled water and no tap water. I do have live plants in many of my tanks, but most of those do not get any added supplements.
<Well, many plants will want at least some hardness, and without carbonate hardness to buffer against carbon dioxide release by night and depletion by day, your aquarium will experience pH changes.><<RMF would blend/mix "some" ordinary/tap water...>>
I assumed the hardness was coming from small bits of uneaten food and fish detritus decomposing.
<No. Hardness is purely inorganic, and almost entirely from minerals in rocks, though some may come from things like snail shells. Note that bones don't affect carbonate hardness because they're phosphate rather than carbonate salts.>
On new tanks over a cycle process it builds up into the 80-100 range and levels off there with water changes. I may skip a water change or two on one of the tanks to see if it climbs much higher than that.
<I see.>
For substrate I use black Tahitian Moon sand in all of my tanks, but this is supposed to be chemically inert.
<It is indeed. While Tahitian Moon Sand has some flaws as an aquarium substrate -- it's damaging to fish that sit on the bottom for example, as Carib Sea state on their web site -- it is an industrial byproduct from glass manufacturing, and should be almost completely pure silicate minerals.>
I do use some reddish pink shale rock as caves and such in a few tanks as well, but I powdered some of the rock and tested it with muriatic acid and it didn't fizz. Could this still be adding to the water hardness?
<Possibly.>
I think I'll also try getting some jars and putting the Tahitian Moon sand in one and some of the shale in another and see if the hardness climbs in either of them. Would help narrow it down.
<Yes and no. An aquarium has a background acidification that causes calcareous minerals to leach out into the water. So while some substrate stuck in a jam jar of water will dissolve over time, the rate at which that happens may be significantly less.>
To respond to some other comments:
I've seen some Distillers capable of producing 600+ gallons per day and they can do it for less than 3 cents per gallon.
<<Not in S. Cal.>>
*Is power much more expensive in California? I'm in Reno, NV and we currently pay 11.5 cents per kilowatt/hour.
<<Our (San Diego) "blended" rate is 2-3 times this... can be higher depending on the f/utilitie's formula for calculating your consumption/charge>
 We worked out the 3 cents per gallon calculation off of that. We're not the most expensive in the nation, I'm sure, but there are areas of the country that pay less than 7 cents per kilowatt/hour, so some places could run distillers for even less.
<Fair enough; as the advertisers say, your mileage may vary.>
=-=-=
Water comes out of my distiller at a PH of 6, <<W/ aeration, time going by, should come up to near 7>>
*I think it does average up higher after it is in the aquariums. As mentioned my tanks test at 7.2 usually. Sometimes they might climb up to 7.5, but a water change brings them back down to 7.2. I don't see much PH variance other than that.
<OK. That's a small pH change unlikely to stress your livestock.>
=-=-=
If you saw the sludge I clean out of the distiller's boiling chambers every couple months you might not want to ever touch straight tap water again either. ;)
<<I'm sure your drinking water is medically, demonstrably safe. Sure, if you accumulate all the detritus over a few months that'll add up to a nice big lump. But if you did the same thing with the air you breathe it'd come out as a big lump of dust and debris as well. The fact is that your body evolved to handle water far worse than anything your water supplier sends down the pipes. Given that the water you get from the tap before you distill it is perfectly drinkable, you're really just wasting energy and water in the process.>>
*We'll probably just have to agree to disagree on this one. :) I've read many articles for and against the drinkability of tap water. All published by scientists and doctors. A doctor employed by the WHO or U.S. Government saying that the water is safe to drink is a bit like a cigarette manufacturer 50 years ago telling us that it's safe to smoke. I doubt it's good for business for the government to tell people they shouldn't really be drinking unfiltered tap water. I've heard it stated that the only reason they don't clean the water up more than they already do is just a cost issue. Government saves a few dollars, and people get exposed to some stuff that may be potentially bad for them long term but has usually has no immediate effect. That doesn't sound too far-fetched to me.
There is also some controversy around water fluoridation, which the U.S. still engages in. I'm sure you can guess that I am in the 'against' group. ;) I'm not alone either. There is a significant portion of the scientific and health care community against it, including members of the Environmental Protection Agency, and even a Nobel Prize Winner. Many European nations stopped the practice between 1971 and 1995, but there are still a handful of countries doing it. Distillation removes fluoride. If interested, you can check this wiki page for more information on it: http://en.wikipedia.org/wiki/Water_fluoridation_controversy
<The whole fluoride thing is another crazy scare. I'm not a medic, but I do have a zoology degree and a PhD, and I think I can tell when an issue is a genuine problem and when it's tin foil hat material. There are things in the world that genuinely do put the future of humanity at risk, like the very real likelihood that human activity is causing the climate to change. But the fluoride added to tap water is a long way down the list of things to worry about. It's a lot like the fuss about nuclear power stations, which are infinitely less harmful to humanity that oil or gas power stations, yet people are terrified of them.><<I concur and am "pro-fluoridation"... Much more positive to be gained than potential trouble/s... I'll even say I'm "pro-DDT"...>>
=-=-=
After distilling approximately 500 gallons, I can pull out a quart of scale and sludge. It's just nasty to think that people drink that stuff and the WHO says it's "Ok".
<<It's not nasty; it's science. Let me ask you, do you drive? I can bet you that driving puts your life at far more risk than anything in your water supply. The thing with human beings is we tend to obsess about trivia while ignoring the big picture. We're amazingly good at this, and advertisers rely upon. If you were given nothing to drink but your potable tap water, I can guarantee you'd live a long and happy life. Indeed, by cutting out alcohol you might even be a bit healthier!>>
* I do drive, but that is a necessary risk in my mind. I need to get to work, go shopping, etc. Public transportation is not exactly efficient or convenient, and riding a bicycle 10 miles to and from work each day would arguably put me in even more danger than being inside the metal frame of a vehicle (not to mention the extra time taken out of my days).
Drinking and using unfiltered tap water is something that I don't have to do since I have another simple alternative available. I'll agree that many people do drink tap water and are fine with it. I'm not. It only takes 1 mistake with the water suppliers and people can quite literally get killed. As you said, US Embassies and stateside federal buildings use distillation and RO/DI to mitigate the risk of water contamination. If they think it's a valid risk, then it seems like a good prevention step to me too. The Reno. NV area usually gets several 'Boil Alerts' each year because some contaminant makes its way into our water. If we missed even one of those Boil Alerts, my family could potentially become ill. With a home distiller, we don't have to worry about it at all.
<<RMF would NOT drink distilled water... w/ or w/o consideration of "Dr. Strangelove's" ref.s to "precious bodily fluids">>
<Again, it's all about risk. Humans are phenomenally bad at measuring risk. If we weren't, we wouldn't play lotteries or for that matter go to church, since both of these depend on us putting faith in something that statistically speaking is incredibly remote, because we're focused on this huge prize at the end. Much the same with why people get nervous about flying or think terrorists will kill them if they go abroad for a holiday, yet the statistical chances of them actually coming to harm in an aeroplane or on a cruise liner are far, far less than the dangers they face at home or in their motor cars. We're just wired that way. If you step back and look at it, it's rather funny. All part of being this odd upright ape we call mankind, who by rights should still be banging rocks together but here we are, chatting about fish via electronics, optic fibres and satellite uplinks. Kinda cool.><<Am still banging rocks together, figuratively>>
=-=-=
Thanks guys. :)
-Chris
<Cheers, Neale.><<BobF>>

RO/DI units  05/23/09
Hello,
<Howdy>
How well do you think a Hague WaterMax would purify my tap water?
<Mmm, hard for me to make out what these folks are selling:
http://www.haguewaterne.com/residential.html
What unit is actually a/the "WaterMax?">
I live in AK and so my choices are limited. I found a person willing to sell me their "hardly used" unit for $125 but have no idea if this is a deal.
<Me neither... but there are okay new RO units for sale at large hardware stores for about this much... Depending on what your source water is like and what you're trying to accomplish with RO/DI... I'd just go with one of these>
I appreciate your input. In my opinion, you maintain the best saltwater aquarium site on the web.
Elizabeth
<Send along a/the spec.s on the unit in question please. Bob Fenner>

GPD and reverse osmosis units, sel.  2/13/09 Hi I am about to purchase a reverse osmosis unit. I have tried to find information online and through books on what gallons per day with RO units means. <Uh, how many gallons per day the unit will produce.> Do you have any suggestions on a RO unit, I think I will choose between the Kent marine Hi-S maximum or the Seachem Pinnacle plus. I have a 155 gal. reef tank with a phosphate and silicate problem due to the town water I have. <Either will work fine, go for the price here. Both are RO/DI units, running the water through an RO membrane first, then through a deionization filter...both will give you great water. Either will also use the same standard 10" replacement filters.> Thank you so much ! <Welcome, Scott V.>

Re: GPD and reverse osmosis units 2/15/09 I am sorry I meant to ask about the GPD thing with RO units was one of the units will produce 200 GPD, one 100 GPD, one 60 GPD, one 35 GPD, why would you need that many gallons in a day? <Oh, I see. Unless you have a large system there is no need for anything larger than the 35 or 60....the big disadvantage to the larger units are the RO membranes. The membranes do require replacement ever few years and the larger units either require much more expensive replacements or multiple membranes.> I do a 25 percent water change every two weeks and have to top off the water every two to three days with maybe three gallons. That is what I did not understand about the units, out of those GPD units what one would you suggest the last three are about the same price and the first one is about 100 dollars more, I do like to buy about the best products I can? <I personally own a 100 GPD unit and would gladly use just the 35, it really is plenty.> Thank you. <Welcome, Scott V.>

To RODI or to RO?   2/11/09 Hey gang, <Hello Alex. Minh at your service.> I find myself in a small rut with my saltwater reef tank lately. Everything i have had has done great up till recently (softies, LPS, fish, inverts). Long story short i bought a clam and it died, so i said to myself...never again! Had my water tested and of only thing that was out of sync were phosphates and Alk both were high phos 1ppm Alk 17 i believe...I will take full blame for the Alk, i miscalculated a dosing of Kent Nano Reef A and B...After talking it over with a couple LFS and some of my fellow reef buddies, it was strongly recommended that i start using RO water, i currently use tap water. <I agree with the advice you were given.> So anyways I am now faced with the dilemma of should i buy my own RODI system or should i just get the RO water locally. I would use it for my 29G...I do 5G water changes once a week but if i bought locally i would do 5G water changes every other week. If i bought my own i would continue doing the same routine only with the RODI water. I know it can be pricey replacing all the cartridges and such so im wondering if i were to buy one and i don't use it that often would it last longer (efficiency wise)? <There are many choices for RO/DI units with varying costs so I will leave the decision on cost effectiveness up to you. One thing that owning a RO/DI unit affords is flexibility and convenience. If time is important to you and you intend to keep your tank for a long time, it could be a worthwhile investment in the long run. Regarding efficiency and filter replacement, if you invest in a good quality unit to begin with, maintenance cost should not be much. For example, the two pre-filters need to be replaced every 6 months, the DI filters need to be replaced yearly and the membrane should last for three to five years with proper use. If you keep up with the filter replacement schedule, limit TDS creep, which happens when the unit is turned on and off often, and install/use a flush valve then you should be able to maximize the life and efficiency of your unit. For more information, review these sites: -http://www.melevsreef.com/why_rodi.html -http://www.spectrapure.com/faq_p0.htm.> Your thoughts and input are greatly appreciated! -Alex <You're welcome. Cheers, Minh Huynh.>

Bad Water! Help! -- 02/06/09 Hello Everyone! <<Hello, er'¦you'¦>> I come to you in a state of confusion...surely you all can help. :-) <<Will certainly give it a try>> I moved a year ago, it was just a five minute drive down a mountain from where I previously lived but the water parameters are amazingly different. <<Ah yes'¦sometimes even within a few hundred yards>> I moved a 125 gallon reef tank to the new house and within a 4-5 month span many of my Zoas and other similar polyps had begun to die...massive 250 polyp colonies. <<Uh-oh>> A few of my prized fish got ich...I have never had an outbreak before. Slowly, some of my fish died. <<Environmental stresses (e.g. -- water quality issues)>> I took my water to be tested and found high phosphates. Shocked I began to do research and found this is quite common. <<Among other pollutants, yes>> I read articles about why and where it comes from along with the harmful affects to corals and inverts. <<All life needs 'some' Phosphate'¦but excessive levels/amounts can be damaging, yes>> I went to my local fish store and they suggested a Kent Marine 2 stage unit for $300. I came home feeling ripped off so I took it back <<Not to kick the legs out from under your LFS'¦but very good RO/DI units can be had for less (too bad the trade won't recognize this and set prices accordingly'¦if only to stay in the game)>> and decided my only choice was to throw in the towel and downsize back to my little 30 gallon which can be handled with gallons of spring water. <<Mmm'¦I see>> I began feeling like I was giving up when I looked at the hippo tang I saved from that same fish store at about a half inch who is now a huge (haha) 4 inches :-). <<A marginal species for the 125 in my opinion'¦has no business in a 30g tank at all>> I would hate to give up on him now he is a beauty. <<Then get/go back to a bigger tank my friend>> So, I read your articles. <<Ah!>> I am looking for a 4 to 5 stage (very high phosphates and probable chlorine) with one or two deionizers. <<One deionization/exchange resin cartridge is plenty'¦ Two cartridges won't make the water any more pure than one will (assuming a 'mixed-bed' resin is used), it simply means you won't need to replace the cartridges as often'¦but when you do it will be at twice the cost, not to mention the higher initial cost for the system. Instead, invest your money in a unit with two carbon block prefilters with successively smaller micron ratings (e.g. -- 5-micron for the first and 1-micron for the second), and maybe even a mechanical (spun poly-fiber) filter before these>> I tried discussing these options with my LFS and they laughed. <<Deplorable>> (Real intelligent group of people). <<I have different adjectives in mind>> I was hoping you might be able to suggest a well rated unit without the bias of commissioned employees. <<What'¦you mean there's nothing in this for me? [grin]>> I am not familiar with these units nor do I have a complex system. I am looking for something that might attach to the kitchen faucet when I begin preparation of my water. <<Most any of the water filtration units will work with/attach to a kitchen sink, though you may have to request that option. Take a look at the five-stage unit here for a mere $135 (second one down on the page: http://www.thefilterguys.biz/ro_di_systems.htm). I and other members of my local marine club have dealt with 'The Filter Guys' on several occasions and can recommend them highly. Be sure to contact them and discuss your needs (make sure you get a faucet adapter) and they will tailor a unit for you>> Thanks for all your help again. <<Happy to share'¦ EricR>>

Source water for SW sys., switching an African Cichlid set up to marine  -- 10/10/08 Hi all, <Marc> I have a 75 gallon tank, with 80 lbs of live rock, a Remora Pro protein skimmer, an Emperor 400 that I just run filter pads with no charcoal, two Hydor stage 4 power filters, and a stage 3. For livestock I have a Yellow Tank, three Green Chromis, Lawnmower Blenny, Firefish, Chalk Bass, Six Line Wrasse, Cleaner Shrimp and assorted snails and crabs. My question is about water changes. I do about a 15% water change every Friday. I test my water, add the necessary supplements, usually calcium and a dKH buffer. I use tap water and mix in Reef Crystals about 15 minutes before i add the water. I know it's not ideal, <Mmm, we'd have to discuss, agree on what is "ideal"... IF your system is doing what you want it to do... the livestock fine... this would be ideal to/for me> but it's not practical for me to treat the water earlier because of a small living space, and my girlfriend not being as enthusiastic as i am, doesn't want two buckets of water kicking around the apartment. And since i only have one day off, I like to get tank done first thing in the morning, and the pet store isn't open early enough for me to buy r/o water. <I use RO for drinking, cooking... tap/mains water for my own tanks> Now that I'm done making excuses, here's my question. Would I be better of doing a water change every other week? It doesn't seem like my mushrooms open up all the way until a couple days after the water change every week. I was wondering, if would be less stressful for the tank, to only do the water change every other week. <Worth trying out> Thanks, Marc P.S. I also have a 75 gallon African Cichlid tank. I was thinking about switching it over to a saltwater tank. My question is, I have about 100 lbs. of lace rock in there, and about 80 lbs. of live freshwater cichlid sand. Could I use the rock and sand for a saltwater tank? <Mmm, some "lace rock" has a good deal of phosphate (can be tested for in a few ways)... and would need to know what the make-up (even just Brand, name of product) of this sand... but it can likely be added, blended with something a bit more soluble, otherwise useful. Bob Fenner>

Reverse Osmosis Filters'¦Cheaper Than Realized? -- 08/07/08 Unfortunately, I did not research prior to buying a used Kent Marine 24 gallon per day unit for the price of $125. <<Mmm, yes'¦a bit of looking around could have found you a 'new' 75gpd RO/DI unit for about $10 more>> I need to replace the membrane, and all three filters of this unit. <<Easy enough to do'¦these units are all pretty much 'standard' and the membranes/other components are easily interchangeable>> I can upgrade the unit to produce 50 gallons per day, but the cost will be $183 to do this. Add this to the $125 cost of the filter, and I cannot help but wonder if I should just purchase a new SpectraPure reverse osmosis filter that will produce 100 gallons per day, at $199 plus shipping. <<SpectraPure is a good product (is what I have), but you can use your current housings and upgrade your membrane and flow restrictor here (http://www.thefilterguys.biz/ro_membranes.htm) for a mere $56'¦plus a little more to replace the other components>> Unfortunately, I already spent $125 for the unit, so an additional $183 to replace the filters and upgrade the capacity to (still) only 50 gallons per day will mean I am spending almost $300 for the unit! <<Do look in to the link I have provided>> I guess my question is: is the Kent Marine filter such a superior product that it warrants such a price ($260 new) for a filter that only produces 24 gallon per day? <<This is for an RO/DI unit? Hardly'¦ Most of these units and components are made by a few manufacturers (e.g. -- DOW) and then distributed and remarketed/relabeled for selling by the different vendors. Have a look around on line at the independent vendors (even those not from the hobby interest)'¦this technology is not/should not be that expensive to utilize>> Regards, Jeff Castaldo <<And to you. Eric Russell>>

Re: Reverse Osmosis Filters'¦Cheaper Than Realized? - 08/08/08 Thanks so much for your quick reply. <<Quite welcome>> I went there, and these guys are even cheaper than waterfiltersonline.com! <<Indeed'¦ TheFilterGuys.biz is a great place to get your RO/DI systems and replacement components. I go to them for my own needs'¦service is excellent>> I am new to your website, but I can see it right now that I am going to enjoy it immensely. <<Ah, welcome then>> Regards, Jeff <<Cheers, EricR>>

Reverse Osmosis'¦Is This A Good System? -- 04/07/08 Good evening Sir, <Many Ladies here as well'¦but EricR here with you this afternoon>> I've had an FO tank for over 4 years now, doing fairly well. Would to move to FOWLR and finally reef eventually. <<Seems to be a popular progression for many>> Problem is that I live in India, and have absolutely no help on proper practices and access to equipment. <<Mmm, well'¦the Internet can likely help with both>> I understand that RO is vital for a healthy reef and since I can't purchase that around here, was wondering if something like this could be used instead? http://www.kent.co.in/excel.htm <<It could be, yes'¦>> Would really appreciate any help that you could offer. <<I'm not sure about shipping internationally, but I think it would be worth your time to have a look here (http://www.thefilterguys.biz/index.htm). Send them an email and explain your situation'¦if they can/will ship to you, I'm sure they will design a system to fit your needs at a fair price. Oh'¦and do spend some time reading/researching the abundance of data on our site re FOWLR and REEF systems. Use the Google search box at the bottom of the homepage to perform keyword searches for topics of interest>> Loved CMA. <<Me too!>> Thank you, Adriel Rebello <<Happy to share. Eric Russell>>

Tap Water Parameters'¦Is a Filter Necessary - 03/26/08 Sorry to bother you all again, Crew. <<No worries>> I have been reading that I may not need an RO/DI unit and may be able to use my tap water by letting sit and buffering for a day or two. <<Depends much on how it will be used/what type of system you have (e.g. -- reef/FOWLR/FO). Some folks can/do get away with not pre-filtering their water. But there is so much that could be in your water that you don't/won't know about (fertilizers, pesticides, etc.) that for me, the investment in an RO/DI filter for marine systems for sure, is money well spent. Even the 'known' issues probably fluctuate in their levels so obtaining an analysis doesn't likely give a true picture of water quality. Heck, when I lived in England for a time I discovered the town where I lived would periodically flush something through the system to kill the freshwater shrimp living within. Since I was not pre-filtering my water back then you can imagine the effect it had on my reef tank (twice!), before I discovered what was happening and began filtering my water as a result>> Here is a list of my local water parameters. Do you think I am a good candidate for an RO/DI unit, or can I just use my tap water? pH = 7.5 Alkalinity = 35 ppm Hardness = 100 ppm Conductivity = 270 umhos Chlorides = 50 ppm Chlorine = 2.5 ppm Ammonia = 0.08 ppm Iron = 0.01 ppm Manganese = 0.02 ppm Phosphate = 0.84 ppm Sodium = 30 ppm Copper = 0.09 ppm Fluoride = 0.25 ppm Lead = 5.8 ppb Nitrate = 0.48 ppm Nitrite = 1.0 ppm <<The presence/levels of Ammonia/Nitrite/Nitrate cause me concern'¦I think the RO/DI unit will be a worthwhile investment regardless of the type system>> Thanks again for your help Matthew Diethorn <<Quite welcome. EricR>>

RO/DI Systems 3/25/08 Good morning crew!!! <Hello Mathew> I am a bit confused about which water to use. I have a 55 gallon tank and currently buy RO water from my LFS. I do not want to do this anymore because it is a hassle, so I am looking to purchase an RO, DI, or RO/DI water system for my home. I am a bit confused about all of the differences in them. I do not really want any waste water. I believe I have read that DI units do not produce any waste water but the chemicals can be hard to deal with when recharging or replacing. Does an RO/DI unit produce waste? <Yes.> What do you recommend as the best option for me? <A DI filter alone is not going to give you pure water. Depending on the resins used, they will only remove selected contaminants. Is best to go with an RO or RO/DI system. If waste water is a major concern, Spectra Pure produces an ultra high efficiency model with a waste ratio of 1/1 which is pretty good considering most units will have a 80% or more waste ratio. Look here for specifications on this unit. http://www.marinedepot.com/ps_AquariumPage~PageAlias~reverse-osmosis-deionization_spectrapure_rodi.html Also read here and related FAQ's/articles. http://www.wetwebmedia.com/h2opurifiers.htm Thanks for your help <You're welcome. James (Salty Dog)> Matthew Diethorn

Re: RO/DI Systems 3/26/08 Thanks for getting back to me so fast. <You're welcome.> I will deal with the waste. I only have a 55 gallon, so I do not need too much for water changes anyway. My last question is....are all of these systems pretty much the same or are some a lot better than others? <I think some are better than others as far as efficiency and quality of the membrane.>  Money is a slight issue. I don't want to spend too much. I found this on Ebay and it looks pretty good. What do you think? http://www.abundantflowwater.com/html/aquarium_filters.html <Not bad for the price. I'd go for it. A Coralife 3 stage unit generally sells for $120.00 at most etailers, but no DI filtering.> Thanks for your help again. <You're welcome. James (Salty Dog)> Matthew Diethorn

Quest For The Infallible Purifier -03/17/08 Hello, I've been struggling with Diatoms for months now. My tank is 2 & 1/2 years old. I know that Diatoms feed on silicates so I couldn't figure out why I have clouds of them when the only water I've ever put in the tank is Deionized. <Clouds of diatoms? Really?> So I decided to increase the size and frequency of my water changes thinking that organics and maybe nutrients had built up over the years. This only seemed to compound the problem. So I tested the Deionized water for silicates and sure enough the Seachem test revealed a level of 4 mg/l. My Tap water Purifier's life isn't even half over. So do you know of a Deionizer that will perform better than the one I've been using? Maybe one that will thoroughly remove silicates up to 75% of the Ion-exchange resin's life? I don't understand why these resins stop removing silicates so soon. Do you? <I'm not sure what brand/type of unit you're currently using, but most the RO/DI units sold in the aquarium business remove just about everything (all silicates, etc.). Spectrapure is one such good brand (in my opinion).> Thank you, love the site, Greg <De nada, Sara M.>

Re: Quest For The Infallible Purifier 03/18/08 Yes, clouds, but Your being surprised has got me thinking that maybe they aren't diatoms. Is it possible to have the clouds and not have them on the rock and panels? <I honestly don't know what's "possible." But I've never heard diatoms described this way.> Do they first cover everything else before they cloud the water? <They don't usually cloud the water as much as they cover surfaces (rocks, glass, etc.). You might have a phytoplankton bloom in your water column. In which case, ironically, I would suggest the use of a diatom filter (or diatom powder used in an suitable canister filter).> They certainly look like the diatom "dust" that I've read about in terms of color and particle size. <Diatom powder is substantially different from the live diatoms than grow in our aquariums.> I guess the best thing to do is send a sample to a lab. Do you recommend this? What would you do? <If you want to, go ahead. It's always helpful to learn. Though, it might be more fun and educational to get yourself a good microscope (always a good investment for a reef aquarist) and try to see it for yourself. :-)> Thanks <Best, Sara M.>

R/O vs. Distilled 03/04/2008 Hi, <<Hello, Andrew today>> Recently I sent an employee to a different aquarium to get water for our reef tank. The owner was very negative about R/O water (i.e., a poor attempt to duplicate natural water, etc). He said that distilled water was far superior. <<I personally don't actually think there is any noticeable difference between the two types of water besides cost. Distilled water usually costs more to self produce than RO or RO/DI. Using in the marine aquarium, well, you wont really notice any difference at all. I certainly would not state that distilled is "Superior" to RO or RO/DI>> Previously, in a pinch, we have used our tap water which is hooked to a distiller. However, I have never read anything about distilled water being superior. What are your thoughts? <<As above. Mainly its down to cost. Most people realise this over time and go and purchase their own RO unit>> Thank you, Kathye <<Thanks for the questions. A Nixon>> Water Treatment 2/22/08 Hello Crew; <Hi John> I am perhaps at a point where I can no longer deny that I will have to get some type of water purifier to generate sufficiently pure salt water for my 180 reef tank. For the past year I have been using store bought RO, in the hopes that once my Chaetomorpha is sufficiently established in my refugium, I'll be able to just use de-chlorinated, Lake Ontario, tap water (which actually tests below the detection limits for NO3, PO4, & SIO2). Trouble is, while my Chaeto is growing okay, it is not yet sufficient to reduce the nuisance algae in the display. Meanwhile, the use of store bought water is getting pricey. <Amen.> In looking at the options, I find the profligate waste of RO and RO/DI to be unconscionable (I live in an area where I have to pay for my water use, and also, in a northern climate, using the waste water to water the lawn would only work half the year!). <Could use for an ice palace:)> So, I am leaning towards a DI system. The trouble with these seems to be that, without an RO as a "pre-filter", the resins don't last. Then I thought that a household water-softener would have all kinds of capacity, but it produces sodium-rich water while leaving the phosphate, nitrate, and silicate alone, and in fact removes the calcium and magnesium which we probably might want to keep anyway. In short, it removes the wrong type of ions. Now I'm thinking; "Hey, why not just use an anion column to remove the negatively charged ions, leaving the positively charged ions, such as calcium, in the water?". I'm wondering if the reason DI resins are short lived is because they quickly become saturated with Ca+? So, if we don't bother trying to remove the calcium, the resin may last a whole lot longer. <There are a few types of anion resins and selecting the right one for what you want to do is important. The basic general purpose anion is basically a de-alkalizing resin, wouldn't want to use that. The anion tannin resin is for removal of color, organics and tannins. The nitrate removal anion resin is a relatively new technology and is one of the first resins that favor nitrate removal over sulphates and other ions in the water. Then we have the anion silica resin which removes what it says. The ProSelect Company does manufacture all of the above resins, and if you would like more info on their products, you can contact them at info@swtwater.com.> To this end, I thought a "cheapy" system could be built just using an AP "Tap Water Filter" (or similar product) with a household carbon block prefilter. <If you think buying RO water is expensive, wait until you see the bill the AP filter runs up, very inefficient vs. cost.> Once the original resin is "pooched", it could just be replaced with anion exchange resin rather than mixed resin. The only trouble I see is if there are some cations that should still be removed; and adapting a column meant for a cartridge, for use with, say, Kent anion resin. Do you know if this has been tried before? Does it seem viable? <Do not, but let me give you a suggestion...is a method I use. I aerate my freshwater for 24 hours to remove any excess CO2, I then run this water through a canister filter with one unit of Chemi-Pure for another 24 hours. The end result is crystal clear freshwater with most if not all contaminants removed. Depending on the volume of water being changed, you may want to add more time to the Chemi-Pure process. Been doing this for years with excellent results, and is very cost efficient. After this process is done, do store the Chemi-Pure back into it's container for future use. I will do about 40 ten gallon changes before I discard the Chemi-Pure. James (Salty Dog)> Regards; John T.

RO/DI Filtration Units'¦Size Standardization/TFC Membranes -- 01/10/08 Hello everyone, <<Greetings Ryan>> I have burned another workday reading WWM, <<Ha!...don't get caught!>> there is a lot of great information out there. <<Indeed>> I have been looking at RO/DI units from The Filter Guys and had a couple of general questions. <<Okay'¦ And by the way'¦can speak from experience/will endorse The Filter Guys as a good resource for RO units and supplies>> No matter which brand you buy the replacement filters are basically standard sizes right, you can buy replacements from other manufactures can't you? <<Correct. There are larger 'commercial' units/components available, but usually unless stated otherwise, most all prefilters, carbon blocks, membranes, et al for 'residential use' are sized/standardized to fit these units. You can even buy and use components from your local hardware or home store>> I want to be sure I don't buy a unit that a couple of years from now I won't be able to find replacement media or membranes. <<Shouldn't be an issue>> Also they (Filter Guys) have 2 different 6 stage filters- both have 3 prefilters, but one has 2 RO and 1 DI and the other has 1 RO and 2 DI's. Is there a benefit to going one way or the other? <<The unit with two 'membranes' is designed for double the output. The unit with two 'DI cartridges' just means you will be able to go longer between maintenance/media changes'¦no real value re 'better' filtering capacity>> Will 2 DOW Filmtec 75GPD RO's cause less waste water or more, or is this just to increase the GPD's and there will be the same amount of waste water. <<Any increase in 'gallons per day' results in a corresponding increase in 'waste water.' There are ways to increase output versus the amount of waste water (e.g.- ensuring optimum water pressure and temperature), but for most locals, the concern for waste water from these units is overrated'¦in my opinion. If the thought of this really bothers you'¦divert the waste water to your garden (as I do), or even to your washing machine for use there>> Is one RO and DI enough or is there benefit from having 2 of either. <<The only benefit is if you need the additional output a double-membrane unit can provide. The double-DI unit; if functioning correctly, should remove everything it will on the pass through the 'first' DI cartridge>> Also are DOW Filmtec RO's the TMC's I read about on your site, I take it they are? <<I think you mean 'TFC' or Thin-Film-Composite'¦and yes, I do believe the 'Filmtec' membranes to all be 'composite' membranes. You 'can' also use the CTA (Cellulose Triacetate) membranes, but these are not resistive to bacteria, and some consider them inferior to the TFC membranes and to have a shorter useful lifespan>> Also I have read this on your site but want to confirm that I am better off installing the unit after the water softener right, my pre-softener water hardness level is 12? <<Mmm, yes'¦the RO/DI unit should be the last stage of your aquarium-use water treatment>> I realize this is a very convoluted question, but I am hoping to only make this investment once. If there is a different path I should be taking please point me in that direction? <<Many choices out there'¦ You can get as elaborate as you want/can afford, but in my opinion a four-stage RO/DI unit will serve most any aquarist's needs (1st stage* 5-micron polyester filter, 2nd stage* 1-micron carbon block filter, 3rd stage* TFC RO membrane, 4th stage* mixed-bed DI resin cartridge). An 'add-on' option you should also consider is a 'membrane flush kit''¦can greatly extend the life of your membrane>> Thanks for all your help. Ryan from Colorado <<Glad to help. EricR from warm (72-degrees!) but rainy South Carolina>>

Tap water purification -12/25/2007 Ordered an RO system the other day from CostCo. only $140 with faucet, storage tank and I believe output is 50 GPD. better to have control of water. thanks for the response. I was concerned with the water bill (utilities are insane). anyhow, our bill is about $2.50 for every 750 gallons. Therefore, cost is not a concern and I will drain the water to lawn via our basement sump or run to garden. <Ah, good idea!> Would cost less than running a filter on tap 24/7 with average results and save cost on Brita filters. <yep> Only writing back so others can see, thanks again, love the site. mike in CT <Thank you, Sara M.>

Zero waste RO  11/16/07 Hi, <Jae> was wondering what you guys think/know about the Watts Premier Zero Waste RO system (Costco). was thinking of getting one. Seems like a very cost effective idea? <Oh yes... A winner. CostCo makes few mis-purchases... (and backs all): http://www.costco.ca/Browse/Product.aspx?Prodid=10289835> thanks as always Jae Lance <Welcome, Bob Fenner>

From Tap to RO Water  11/5/07 Hello Our marine tank is currently set up using treated tap water (the advice we were given!) and we now wish to change to RO water. <good> We were thinking of purchasing RO water and using it for our future water changes but I am concerned about whether this may have any negative effects or cause any problems. <Hmm, I'm not sure what you might be worried about. You're going from lower-quality water to higher quality-water. What could be the negative effects? Just make sure that when you add the new water (with each water change) that it's of the same/similar salinity, temp, alkalinity, pH, etc. as your tank water. But you should do that with any water you use for water changes (RO or tap).> Our system is just a couple of months old and we have 2 common clowns. Kind Regards, Sian <Best, Sara M.>

Culligan RO water for Reef Tank 11/3/07 WWM- Hello. <Hello, Scott V. with you.> I have a 75 gallon tank with several fish around 90lbs of live rock and few corals. A friend of mine is an independent "water guy" - he sets up in-home water systems and such. He has been giving me five gallons of RO water ever 1-2 weeks to top-off my tank. But, it is getting to be a hassle to run to his house, or having him drop the water off at my house. At our local Wal-Mart, Culligan has a station that sells water for 33 cents a gallon. I would much rather prefer to just pick up five gallons quick while shopping than have to depend on someone else to get my water. It states that this water goes through a 4-stage filtration process. The source water is tap water from local municipal water systems. The four stages of filtration are: sediment filters, activated carbon filters, reverse osmosis, and UV light. Is this water to be trusted...have you heard of others using Culligan Water from Wal-Mart stores for reef tanks? Thanks for all you do, WWM Crew! <I have done this and tested water from various stations in my area to confirm what they claim (they weren't necessarily Culligan). Fact of the matter is that some of the water was ok and some wasn't. You could test the water for nitrates, carbonate hardness and even chlorine to confirm the filtration claims. Most local fish stores sell ro/di water that would be suitable. It would be easier and cheaper in the long run to consider your own personal reverse osmosis filter. Thank you for the kind words from the crew and I, Scott V.>

Re: New to saltwater- need for RO/DI filter? -- 09/13/07 Hi. I've wrote to you a few times in the past about my 75 gallon FW tank. Well, the other day I caught my daughter "cleaning" the tank with half a bottle of Windex. After a complete tear down I've come to the conclusion that I would like to re-set it up as saltwater. <Yikes. If you're going to start over again, venturing into saltwater, please do have a long discussion with your daughter (and other non-aquarist kids/significant other/everyone) about not touching your aquariums without asking you first.> I've purchased Mr. Fenner's book and I must say, its a wealth of knowledge. I have a few questions I'd like to ask. I've been looking into filtration. Fluval 305-405 canister filters are where my attention is turning. I've been researching filters from many places, looking at pictures, random message boards, and they all have pictures of sumps posted. Is a sump the best thing to use or would the Fluval canister be sufficient? <A sump is usually preferred. The Fluval might be ok for a lightly-stocked fish-only tank, but it's going to be a real burden to clean. And you would have to clean it often. See here for more info on canister filters for marine systems: http://www.wetwebmedia.com/marcanistfltfaqs.htm> I'll be using live rock to help with the bio-load and am interested in some anemone but these are not necessary now. My question is would my regular light be fine for the live rock? I know that I would need special lightning for the anemone. <You don't necessarily need any special lighting for live rock.> I've also been researching RO/DI units. Its within my means to get one but if I don't actually need one at first I'd like to save a little money. <Get the RO/DI unit if you can. You'll absolutely need it if you ever want to keep an anemone. See here for more info on RO/DI filtration: http://www.wetwebmedia.com/rofaqs.htm> (I have to hide all my receipts from my wife so she doesn't know how much I've spent so far). <LOL I tried to convince my husband that the RO/DI filter was for our drinking water too. He wasn't so convinced, but some people do buy RO/DI filters for their own drinking water.> I know that they are recommended but could I get by without one until I decided to add the corals and anemone? <You could get by without one for just fish. However, you'll want to have all RO/DI water before you even think about corals and anemones. You could also buy RO/DI water from your LFS.> Would it cause any harm to the live rock and sand? Or any livestock I may get including snails and small hermit crabs? <It's hard to say generally. It just depends on how bad your tap water is and how sensitive the animal is. At the very least, try to get some kind of water filter. Even just a cheap 2 stage RO filter would help.> I apologize if these are asinine questions but I'd like to make sure I do this right. <No problem. Keep researching/reading.> Thank you in advance for your response. <Best, Sara M.>

RO Water and Ammonia...    9/11/07  Hello once again! I must thank you all for this great site and all the help you guys do for us, the average aquarium hobbyist! <:-)> My problem this month... hahah... lies within the Ro water I am using. I buy it locally from a grocery store bottled, its says on the label processed by reverse osmosis. Whenever I mix up a fresh batch of saltwater I always seem to get a reading of Ammonia at 0.3-0.5 Mg/L. <yuck> I wrote the wonderful people at Coralife and they said RO does not remove Ammonium Ions in the water column, and when you add the salt, the salt brings out the Ammonia readings. I use Hagen/Nutrafin test kits for everything and have confidence in their accuracy. The guy I spoke to said to use Zeolite before adding in salt, <?!?> it only works in freshwater. <Hmmm, yes, this is what sewage treatment plants do. But they have specialized zeolithic filters that aren't commonly used by aquarists. There is a product line manufactured by Zeovit which incorporates some kind (unknown) zeolite material in marine aquarium filtration. But this is not for treating pre-mixed water or water for water changes/top offs.> I have a 20g Rubbermaid bin for mixing up water, with a powerhead and heater as well. What do you guys think I should do? 1. Use the Zeolite in a small power filter, before adding my salt? <I suppose this could work if this zeolite material is the kind that removes ammonia. What a lot of people don't understand is that "zeolite" is just a general term for any of at least hundreds of different kinds of porous rock. Some zeolite rocks/powder will remove ammonia, some won't.> If so, how long? 24hrs? 2. Buy a RO/DI 3 stage filtration setup? <This would be my suggestion. Most "serious" reef aquarists have their own RO/DI filters or at least purchase RO/DI filtered water from a LFS.> Will I still get some ammonium ions in my water from using a RO/DI unit?? <If it's working properly, no. RO/DI filters produce water that's pretty much as close to distilled water as you can get. When I use my RO/DI unit, I get a TDS reading of 0.> Thank you for you help in this matter! It is greatly appreciated. <De nada> 55g reef tank, 55lbs LS, 60 lbs LR, 3 powerheads, Aqua C Remora skimmer w/ surface skimmer box. 1 yellow wrasse, Organ pipe coral, 1 skunk cleaner, 2 peppermints, 10 scarlet hermits, 10 Nassarius, 5 red legged hermits. Brad Ketner <Sara M.>

RO/DI question  8/20/07 Just finished your impressive array of FAQ's about RO/DI and other water conditioning. I am starting a 120g reef tank. <Just finished my first cup of Joe... am getting up for a refill> I am hoping that you can help me determine whether a RO or DI or a combination is needed in my case. I want to make sure I provide a good environment for my creatures. <Sounds good> I got a water report done by my water company the contaminants are as follows Barium ppm 0.063 Fluoride ppm 0.86 Lead ppb 3 Nitrate ppm 0.113 Sodium ppm 14.4 Chlorine ppm 1.9 Trihalomethanes ppb 73 <Want to take care of these last two...> Haloacetic Acid ppb 46 Bromate ppb 13 Copper ppm 0.77 <Mmm, likely will complex with synthetic mix...> Thank you so much for your help in advance. <Is there a question here? Are you a strong candidate for RO? RO/DI? Might be... From what is presented, I would just use reverse osmosis... and pre-mix, store new water for a week ahead of use... as proscribed on WWM. Bob Fenner>

Re: RO/DI question  8/21/07 Thank you for your input, based on reviews on the Spectrapure setup from your website I am looking at two different models one is $200 and the other $300, both 60GPD. Will the lesser expensive of the two meet my needs for a reef aquarium. Below are the specs and the filter particle sizes. Thanks alot. <Bob answered the last question recommending R.O. unit. I am a fan of RO/DI for reef tanks. I advocate 0 TDS readings for best results. D.I. unit is required to get that low.> the $200 model is spec.ed Maxpure MPDI SEDIMENT FILTER (SF-MT-1-10) CARBON BLOCK (CF-1-10) RO MEMBRANE (MEM 25-180) * DI CARTRIDGE (DI-SB-CI-10) SpectraPure ® MaxPure T MPDI Systems incorporate high-flow high-rejection TFC membranes, a 1 micron sediment filter, a 10 micron carbon block filter, and a custom formulated 10"color-change DI cartridge. MPDI systems are available from 25 to 180 GPD (95 to 680 LPD) production rate, and come with a 3/4" garden hose adapter. the $300 model is spec.ed Maxpure CSPDI SEDIMENT FILTER (SF-MT-0.5-10) CARBON BLOCK (CF-0.5-10) RO MEMBRANE (MEM S 25-180)* DI CARTRIDGE (DI-SB-10) SpectraPure ® CSP-DI Systems feature SpectraSelect T TFC membranes (guaranteed >98% rejection), a 0.5 µm MicroTec T sediment filter, and a 0.5 µm Carbon Block Pre-Filter (for greatly enhanced membrane life), plus a 33% larger capacity SilicaBuster T 10" DI cartridge. The standard pressure gauge and clear filter housings mean better visibility to system performance. Also included is a filter wrench and a 3/4" garden hose adapter. <These are all fine units. I would recommend a 6 stage unit from the www.thefilterguys.biz/ OCEAN REEF + 2 SIX STAGE 75 GPD RO/DI> <Rich aka Mr. firemouth>

Re: H2O Purifiers 8/1/07 Thank you for your quick response James. <You're welcome.> I live in the suburbs of Boston. Should increasing the contact time still not solve the problem, will DI help? <Deionization generally just removes heavy metals, calcium, magnesium, and salt. I do not believe it is going to do much for phosphate removal. An R/O unit would have been a better choice for your application, as this will produce the purest form of water. When R/O is used in conjunction with a DI unit, you will have produced a very pure end product. James (Salty Dog)> Regards, Kim

RO/DI...Recommendation, check eBay  7/20/07 Crew, <Hi Andy, Mich here.> Not a question, just some info for those looking for a good deal on a RO/DI unit. <Always appreciated.> I did a lot of research on units and about the cheapest I could find was a pretty basic unit for $150. Most etailers I looked at sell the 3 and 4 stage units for $200+. Before I bit the bullet, I remembered that it had been a long time since I bought anything on eBay, so I decided to do a quick search for RO/DI units. Well, I just took possession of a new 100 gpd "Zero ppm" 6 stage RO/DI unit that I bought on eBay for $76 (plus $28 shipping), and the thing works like a champ! My TDS went from 116 to 0. The seller offers various configurations for different prices. <Thank you for this recommendation and reminder. Others will benefit and appreciate. Mich> Andy Thoughts on this RO-DI Unit 6/10/07 Hi Crew, <Andy> Do you have any thoughts/experience with Melev's Reefkeeper, a RO/DI unit that sells for $169 plus shipping (http://www.melevsreef.com/ro_di.html)? I've been researching units, and this price seems too good to be true. I found references to this website on WWM but not specifically to this product. Thanks <Have met this fellow and he is the "real thing"... I suspect this is a fine unit... About what it really should cost. Bob Fenner>

Reverse Osmosis 6/4/07 Can you recommend a good RO unit? I'm looking at a Costco version but wondering of this is same as a RO/Di unit? What's the difference? Thanx for your response Ace <The difference between an RO and RODI is the RODI has an extra stage to remove what little material makes it through the RO membrane. As to whether you need it or not, that depends on your source water. Most RO and RODIs are pretty comparable based on gallons per day, personally I love www.airwaterice.com for their customer service.> <Chris>

RO w/o DI - 5/29/07 Hey Crew, <Dave!> I have looked and looked everywhere I can think of but can not find the answer to my question. I have been reefing it up for about 6 months now and decided to buy a RO/DI filtration system to make the water healthier for my tank. I went to Home Depot and started looking around and the only ones I found were Reverse Osmosis systems without the deionization. <Yes, the units for drinking water don't need to polish the water as perfectly as we like for our reefs.> Nobody seems to have an answer on if the deionization is the part that I need. <It just finishes removing what the RO misses. RO takes out a good bit of junk, but can't get it all. The DI is very thorough, but too expensive to use to clean up all the junk out of the water.> Also it did not mention removal of phosphates on any of the packaging, So I started wondering if possibly the word Phosphate is a generic term for several different things. <No, that is one specific thing, and it happens to make algae grow like crazy.> I did in the end buy a system and it does remove all sorts of things but still no mentioning of phosphates. I guess a chemistry class may be in order. <Heee! Reef-keeping Chemistry 101. If you are not having a problem with phosphates (easy to test source water for) then I wouldn't worry about them. But it should be fairly straightforward to add a DI unit to the back end of your RO system. A simple DI cartridge (or two) should finish removing anything the RO misses. Read here: http://www.wetwebmedia.com/rofaqs.htm > Any help is appreciated, and for the record I started reading on your website a few days into getting started on my reef tank and have been very successful because of it. <Glad to hear!> Also I really want to check out some of the books you guys have out. Can you steer me in the right direction on where to find them, and the names? I can't find the page I found them on before. <Links here to several dealers that carry Bob's and Anthony's books: http://www.wetwebmedia.com/WWMAdminSubWebIndex/dealers_and_distributors.htm I bought 'Conscientious Marine Aquarist' at a LFS, and ordered 'Reef Invertebrates' from MarineDepot.com. > Thanks again Dave <Welcome, Alex>

RO, DI, or RO/DI? - 03/12/07 Hello <<Good evening Pam>> I've been reading your FAQ's about RO/DI's.  I've read positives and negatives on all 3... RO, RO/DI and DI only. <<Indeed, like most all aspects of the hobby...is subject to much opinion.  But even so, I think there are some basic guidelines that can help "you" with your decision>> Some on WWM say RO is a waste because it wastes such a huge amount of water and you should do DI only. <<Mmm...nothing wrong with being "green," but it can be taken to the extreme I think.  Everything has a price, and in my opinion/my locale, the waste water created is worth it to me to operate an RO filter versus alternative methods to filter water for the benefit of my reef.  But if this "waste" is something that you can't/won't tolerate, one can find ways to utilize the waste water...from diverting it to your garden to using it to wash your clothes>> Some say RO is all that you need and DI is unnecessary. <<In some instances, yes.  For a FO or FOWLR system this is often the case.  However, REEF systems often will benefit from the extra "purity" a DI cartridge can provide>> Some say RO/DI is the only way to go. <<If you want what is generally considered the "ultimate" in purity, yes>> I talked to two guys at my LFS, and one said to have my water tested, and I may only need a RO unit. <<Good advice...depending on your system>> The manager at the same LFS, said for only $50 more, it would be crazy not to get the RO/DI. <<Arguably this too is good advice>> I haven't had my tap water tested.  I have city water and a 53 gallon tank that I just bought.  Confused on what I should buy.  Everyone seems to have a different opinion.  Help!  :) <<Personally, I prefer a combination RO/DI unit for "any" marine system, but hopefully you are gaining enough information to make your own decision>> Thanks, Pam <<Quite welcome...happy to share.  EricR>>

Re: RO, DI, or RO/DI? - 03/12/07 Thank you Eric. <<Quite welcome Pam>> I was leaning towards RO/DI....and you helped convince me that's the wisest decision. <<Excellent>> This hobby is soooooo expensive...that it's not worth chancing trying to filter with RO only or DI only. <<Have their places as separate entities...but as I stated, I prefer to use them in combination>> Thanks again.  You guys are the best!! Pam <<We do try [grin].  Eric Russell>>

RO vs. Distilled 2/02/07 Crew, <Celeste.> Quick question.   <Answers to follow suit.> Our water is very hard.  We've been working on trying to lower it by mixing our filtered water (using an Ecoquest living water system that removes the bad stuff but leaves all the minerals, etc. in) with RO water that we've gotten from the store.   <?> We wanted to make sure it lowered the hardness before investing in an RO unit.  After a week or two, we tested it, and our hardness hadn't dropped at all.   <Not exactly clear on the methodology being used here. It sounds like you take RO water, and then mix at an unspecified ratio with water from a drinking water filter. I wouldn't bet on the repeatability of the results with these "trials" in water chemistry. Furthermore, the RO that the store is using may be long overdue for a cartridge replacement. > We tested the RO water, and it's at 11!   <RO doesn't remove everything, but should be a lot softer than that compared to your tap-water.> <<Should be much softer than this... RMF>> Not soft at all.  (Our filtered tap water is 13.)  We've been using distilled water and it's dropped it down quite a bit.  I've been researching and getting confusing information on whether RO in itself is soft or if it depends on your tap water to begin with or whether the store we were getting the water from just never changed the filters or something.   < http://www.wetwebmedia.com/ca/volume_2/cav2i4/RO_systems/reverse_osmosis.htm> If we bought a RO/DI unit, would it soften the water, or should we look into getting a distiller that leaves the water extremely soft?   <The expense of distilled water is prohibitive, IMO. RO/DI in a five-stage configuration will leave extremely soft water.> Thanks again, and I'm sorry if this is answered somewhere.  We really appreciate all the help with our tanks: articles, FAQs, and answering our questions. <Not to worry, Celeste. Good luck! -GrahamT> Celeste

DI vs. RODI in NYC   11/30/06 Hello, <Hey Dylan, JustinN with you today.> There are many informative responses to the FAQs on your sites RODI page. Thank you for those! <You're welcome, from all of us> I am still wondering if I can get away with using only a DI unit in New York City. The water here is very good for drinking, but I live in an older building and know nothing about the state of the pipes. Furthermore, I am concerned that if I don't spend the extra cash now for a RODI unit and instead just use the DI unit, I will pay in the end when something goes wrong in the tank. (Yes, I know that might be a little dramatic). I am new to this hobby...this is my first reef setup as an adult after a childhood of watching and helping my dad...so I would like to make it as smooth a start-up as possible.   Any advice will be greatly appreciated. Thank you, Dylan <Likely you would be fine with either an RO-only unit, or a DI-only unit, but given the choice of the 2, I would choose the RO. Replacement parts and filters are usually cheaper than large quantities of DI resins. No worries though, either should serve your purpose well. Hope this helps! -JustinN>

Re: DI vs. RODI in NYC   12/1/06 Justin, It's either a RO/DI or just a DI. How could they both do the same thing or produce an equal end product? Why should I use the RODI versus just the DI, other than price, for the water for my reef tank? Thanks, Dylan <Well Dylan, both outputs of <sic> deionization is extremely pure water, the difference is that an RO/DI unit will not extinguish your deionization resin as quickly as a DI unit alone, because of the initial level of cleansing handled by the RO unit. Beyond this, functionally they will be very much the same. Either will work here. Cheers! -JustinN>

RO Units...Which One?, What Configuration? - 09/06/06 Hi Crew, <<Hello!>> Thanks for taking my e-mail today. <<Welcome>> I have finally decided to buy my own RO Unit to supply my 75 gallon reef tank. <<Cool!>> I was looking at a few different units and was wondering if you could help me clarify a few things. <<Ok>> First off, I live in Saint Paul, MN and my water comes from the Mississippi. <<Via a water treatment facility I hope>> Second, I live in a 100 year old house and I assume some of the plumbing is fairly old. <<Mmm, a fair assumption...> I was looking at the Kent Marine Hi-S and Maxxima Units as well as the Pinnacle + Units. <<You might also want to peruse what is available at your local home center (Lowe's, Home Depot, etc.).  All RO units operate on the same principle, and the membranes used by all are made by just a few manufacturers...you might find you can save some considerable cash by buying/configuring your own unit from other than a retail "fish" outlet>> My first question is if you know the difference between the Hi-S membranes and the TFC membranes (i.e. is the Hi-S as good at removing things other than silicates?). <<Not aware first-hand, but would assume as much.  A search of the NET should find rejection-rate tables re that will allow you to make comparisons, but unless you "know" you have high silicates/have a silicate problem you probably don't need to spend the money for the Hi-S membrane>> Secondly, with my water source, would you recommend getting the Pinnacle because it has two carbon pre-filters? <<I prefer "two" carbon cartridges on my system for the extra "capacity" provided.  My recommendation here is to utilize the "solid block" carbon filters with "micron ratings" for particulate removal (5-micron for the first stage...1-micron for the second).  Periodically removing and rinsing under the tap will extend their utility>> Third, if I get the Pinnacle would you recommend hooking up a DI filter inline? <<Indeed...as the last stage of the filter.  Another money saver here is to purchase a "refillable" cartridge and buy "bulk" resin from someplace like Resin Depot (ResinDepot.com).  Initial cost more, but you'll save about 75% or more (depending on how much you pay for the "disposable" resin cartridges) over the long term>> Also, I was planning on hooking up the RO Unit under my kitchen sink.  Can I run the unit from my cold water source or do I need it to be temperature controlled? <<The units operate more efficiently when the water temperature is above 70F (my unit's output doubles during the hot summer months due to an increase in source water temperatures), but trying to regulate this is likely more trouble than it's worth, and you certainly don't want to hook the unit up to your hot water line...just plumb to your cold water source>> Do you have any tips on hooking it up under my sink?   <<Nothing special, merely follow the manufacturers instructions.  A keyword search on the NET also yields much info re>>    Thanks very much for the help, Tim <<Is my pleasure to assist.  Regards, EricR>>

Which RO Unit? - 09/30/06 Hi, <<Hello>> I was wondering if any has used any of these products, Coralife Pure-Flo II RO unit or Seachem pinnacle 35 gpd RO units? <<Afraid not>> The reason I need a RO unit is because my tap water is very hard (300)with a very high pH (8.4), and I want to keep fish that require a low pH and soft water. <<I see>> Are either of these systems any good or would you recommend a different brand. <<Either will work fine.  All these units operate on the same principles...you could even obtain a (cheaper) unit from someplace like Lowe's or Home Depot>> Thanks, this is the best website for fish info and advice I've ever been on. --Sbatiste <<We're pleased you find it useful.  EricR>>

- Kitchen Water Filters - Can you use sink water filters for saltwater changes. Having lots of problems with diatoms in the last 4-5 weeks. My tank has been up since Oct and never had a problem till now. I have been using the tap water from the first. Now I'm getting this algae. I have a Brita filter on the sink and thought it would take the chem.s out. <Would certainly take out the chlor-ines/amines... would mean you'd need to change the filter cartridge more often.> I do water changes every other week but been doing them more often since this is going on. I use the conditioner to take out the chlorine and such and use instant ocean. I've read about the other filters to use but so expensive. I thought about the Brita on the faucet. <Will take out some stuff, but not all... not diatoms.> Please let me know thank you. <Cheers, J -- >

Kati Ani deionizers... DIY units 9/20/04 Anthony, I know you like the Kati  & Ani units for water purification. <yep been using them for over 10 years> I am trying to locate a Kati & Ani 2 but am having no luck. Dr. Fosters only have the Kati 10 but have the Ani 2. I did a search on Google but couldn't find anyone else that sells the Kati & Ani units. Any ideas? Thanks Pat <no worries... better still is the bulk resin for DIY canisters or Kati Ani replacement. Spectra-pure sells them at: http://www.spectrapure.com/St_replac_p5.htm best of luck, Anthony>

RO/DI or Kold Ster-il 9/8/04 Thanks, Bob - <Anthony Calfo in his stead> I guess I'd also like your opinion as to the quality of water produced by the Kold Ster-il vs. the RO units, please. Dave Parker <hard to compare... apples and oranges really. Kold Ster-il produces highly filtered water... but does not demineralize like RO or DI. Some people have decent tap water with desirable mineral content... just in need of cleaning up some of the nasties (chlorine, phosphate, etc). For such situations... Kold Ster-il is excellent. But for worse source water (quality or variability of composition) or for aquarists that simply want better control over the water used/produced... then demineralizing and then buffering back up (with desirable elements of hardness) is the way to go vis a vis RO or DI. I personally favor DI as there is no waste water produced and the recharge chemicals are dirt cheap and be neutralized to inert so to speak. RO instead wastes a lot of water with even expensive units and the cartridges are an ongoing and considerable maintenance expense. Best regards, Anthony>

RO/DI or Kold Ster-il 9/8/04 Thanks, Anthony, <always welcome :)> If I understand, I can produce top-quality water, then using a Kold Ster-il followed by and add-on DI stage, and produce no waste water.  Is this correct? <hmmm... my apologies. I may not have been clear. The first thing you need to decide on is whether you need ultra pure (ala distilled) water from an RO or DI that you are willing to NEED to aerate and buffer before every use. This is the most work on your part, but produces the most reliable, clean water for evap top off or for salting for marine use. But it is dangerous to use raw untreated (unbuffered) DI or RO (or distilled) water. Yet... this is what many aquarists choose to do, myself included, to insure superb source water. Kold Ster-il units on the other hand do not demineralize water but leave in Calcium, Magnesium, etc. They are basically top shelf chemical filters that clean up the water quite a bit... but do not reduce the conductivity/hardness, etc. It is an outstanding prefilter for a DI... and if your tap water is not too bad... can stand alone without even needing a DI or RO. DO test your tap water to see how bad is bad first. Ultimately, the Kold Ster-il  + DI units an excellent choice in my opinion> thanks for bearing with me, Dave <no worries. Anthony>

RO/DI or Kold Ster-il II 9/8/04 Thanks again, Anthony, <cheers again> I always aerate and buffer with SeaChem Marine buffer before adding my salt - I happen to use Oceanic if it matters.  I understand about not using distilled or raw, RO/DI as top-off - heck I don't even do this for my goldfish tank.  I'm simply looking for a way to produce top-quality water for this process without wasting 4x what I produce, <ahhh... definitely DI then for you> and to be able to produce it more on-demand since no one is home during the day to watch the RO unit overflow my Rubbermaid cans. <no worries... you will have this with DI. But with either... there is always a simple float switch for your reservoir> I have a whole-house water softener, so that much waste water gets expensive, and I believe (correct me if I am wrong) that my water softener will take a lot of the calcium and magnesium, in particular, out, but leave some sodium (or in my case, potassium) in.   <yes... true. Salt softeners are NOT recommended for use with aquatic life. Long term problems with water quality> Do I need ultra pure?  Well, I get algae blooms like crazy using tap, that is why I started hauling RO from my LFS. So I guess I may not have been clear, either - I want to produce top-quality raw water, with as little waste as possible, and am in the practice of buffering and aerating and buffering already. To ask the question another way, what am I likely to leave in my water by using Softener -> Kold Ster-il -> DI stage vs. having an RO unit in the middle, and is this difference enough to cause problems down the road. <just use the Kold Ster-il & DI stages... never the salt softener> Appreciate the help and advice, Dave <best of luck, Anthony>

RO/DI or Kold Ster-il Hi, Gang and thanks for a great service!  I am setting up a new 120gal FOWLR, and am getting tired of hauling RO water from the LFS. <I hear you... my arms are a good inch longer from hauling water about all these years> I'm ready to put in a system myself.  However, I am scared by all of the waste water the typical RO/DI units produce, as water is not cheap here. <Mmm, I divert the "waste line water" to my pond outside, and in turn to the garden> I've heard about this Kold Ster-il unit, and that it does not produce wastewater.  Can you help me understand the difference in the processes, and perhaps suggest which might work best? <This unit uses filtrants that are not re-used... contactors... so all water that is filtered, passes through the unit is used. RO utilizes selective membranes capitalizing on ambient or increased pressure to "squeeze" water molecules and exclude solids (and their zones of hydration) and some other liquids, gasses from getting through the membrane... with their water periodically bypassed to waste> Either system would come after my water softener, and in this, I use potassium chloride rather than sodium chloride as the agent to wash/renew my resin bed.  Thank you for your input! Dave <The real (IMO of course) difference in practical terms are the upfront costs of the two types of units/technologies, versus the amounts of waste water generated... Both will produce high(er) quality water of use. If it bothers you to "throw away" so much RO waste water (a ration of 4-5 to 1 of usable is not uncommon) than I would go the contactor route. In all fairness though, do take a look at your water bill, see how much water is going for other uses... Bob Fenner> Finding a 2-column Deionizer 11/8/04 Anthony, I am trying to decide on a RO/DI product. You said to look into a 2-column deionizer as a possible choice. I have not been able to locate a manufacturer or distributor for this.      Do you or can you give me a short list/recommendations for these?. Thanks Keith                                                              <a simple keyword/phrase search on google for "deionizer, aquarium" and like entries will yield good leads my friend. Any of the big mail order companies too carry deionizers: Marine Depot, Custom Aquatic, Drs. F&S, etc. The brand I have used for years is "Kati Ani" from Germany. Anthony>

Google, Google, Google till it hurts! Kati Ani dealer 11/9/04 Hello All!! <howdy> Anthony, in response to a deionization question yesterday you mentioned that you personally use the brand Kati Ani from Germany.  Are you referring to Kati Ani generically or is that the actual brand name.  I asked because I have seen many other recommendations on this product before but cannot find a distributor or a manufacturer's website.  I believe it is made by AquaTech, but I cannot fine their website.  If you have any info to point me in the right direction I would be quite appreciative. Thank you kindly, Corey <my apologies for the title to this e-mail, my friend... but I am rather frustrated today - feeling like an enabler - with friends/queries from folks with seemingly little effort to do a simple keyword search to help themselves <sigh>. To help you and illustrate a point... in response to your question, I simply went to the google search tool which is plastered all over our website and well known at large. I typed in "Kati Ani price" (three common words that would appear on a page with this product if it existed out there somewhere)... and the very first page that came up has a link to: http://www.drsfostersmith.com/product/prod_display.cfm?pcatid=4499&N=2004+22789 ironically... this merchant is also an advertiser. Our only advertiser on WWM at present: Drs Foster and Smith/LiveAquaria.com I'm sure there are other merchant of this product out there... google till it hurts, bro. Anthony :)>

- RO/DI Evaluation - I bought this unit and will be receiving it tomorrow, I have found 1 previous post about this unit. It is mfg. Water General and it's cost is minimal, it is a six stage unit will you please evaluate and let me know what you think of this unit in comparison to a SpectraPure or Kent Marine.   http://www.watergeneral.com/support/html/RD100.htm <I'm afraid there just isn't enough information there to form an opinion. Most RO/DI units are very similar and vary mostly in configuration from manufacturer to manufacturer. The parts used in each are for most intents and purposes identical. I'm sure this unit will treat you fine. Cheers, J -- >

- RO/DI Evaluation, Follow-up - the question was about the rejection rate in the other post. <I don't see any information there about rejection rate, but four to five times the output volume is not unusual.> But I am just curious if this unit is going to give me quality water for a reef tank. <I'm sure it will be fine. Cheers, J -- >

- Distilled vs. RO - Hi gang, <Good morning, JasonC here...> The plethora of information contained in WWM always astounds me... keep up the great work! <Ok.> I'm presently using a distiller for my aquariums... it's small, uses about 750W of power, and takes about 3 hours to make 3 quarts or so of distilled water. <Not a very efficient way of producing water for your tank.> I've been considering installing an RO system, but know the membranes, pre-filters and DI canisters are rather costly. <Not as costly as your electric bill...>  Has there been any cost studies on RO water -vs.- Distilled? <I think you and I just did one... at this rate, you can buy new membranes, which last for years when flushed with the money you save from not running your distiller.> I know the RO system would be far more convenient... BUT... I can live with the distiller for about $10/month!  <An RO filter would produce much more filtered water per dollar than your distiller.> FYI- Our tap water is quite hard, 30 or more dKH, high in nitrates and high in particulate matter...JOY, huh? <Just order a back-flush kit to go with the RO device and the membrane will last a good long time.> Any information and/or experiences on this would greatly be appreciated! Cheers, Michael <Cheers, J -- >

DI Water 7/13/03 Hi.  I have a question about treating tap water using a DI unit.  What all does DI remove and what will it do to the water in terms of pH and hardness?   <it varies by resin brand/quality... but better units almost completely demineralize water (zero hardness). pH will likely be acidic or at least unstable for the lack of buffers. It needs to be aerated and then re-mineralized slightly before use. There really are many FAQs and information on this subject in our archives at www.wetwebmedia.com  Do a keyword search on the subject with the Google search tool at the bottom of the homepage> Kent and some of the other manufacturers are less-then-clear about what exactly their units might and might not take out and how it will change the water's chemistry.   <just one of the many reasons why I do not use or recommend Kent products specifically. I have been quoted as having said that I would not take their products for free> I am considering purchasing a unit to help combat tap water that is less-then-ideal for my reef tank and a possible Discus tank that I may be setting up in the next few months.   <excellent and agreed... do look at the Kati Ani brand (Dr.s Foster and Smith, Gwynnbrook Farms, etc). I have been using this brand for over 10 years [in my discus hatchery and an industrial sized one for my coral farm/greenhouse]> Will DI water be beneficial, and is it better then RO <I think so as many do... arguably produces slightly purer water> (I don't like the idea of how wasteful RO seems to be)? <agreed!> Thanks! Christopher <best regards, Anthony>

- Dealing with Marine Velvet & RO/DI Clarification - Thank you for your prompt reply to my previous question on Marine velvet.  My Cuban Hog , Flame hawk and Zebra Moray Eel have all survived the attack of Marine Velvet.  The Cuban and Flame hawk are eating well and swimming normally.  I am planning on not adding any other fish to my 200 gallon tank for the next 6-8 weeks to break the cycle of this parasite.  <You won't accomplish much as long as there are fish hosts in the tank.>  My question is can I keep these three in the main tank.  <No, they should be in individual quarantine while you let the tank go fallow, also chance to treat the fish apart from the tank if something were to reoccur.>  I know you've said that the tank has to remain fallow without any fish to break the cycle.  <Heh... I just said it again ;-) >  I'm wondering if the Flame hawk and Cuban Hog have developed some immunity to the Marine Velvet which would allow them to stay in the main tank.  <Fish that are in excellent health can fend it off to some extent, but I'm going to guess that your fish are under some extra stress, given that you used the phrase 'survived the attack' - I would guess you will see the velvet again.>  Would a UV aid in minimizing the outbreak of these and other pathogens.  <Only to a very small extent... I don't really endorse the use of these unless of a hospital system. Can do without UV by careful use of quarantine.> My second question is about Reverse Osmosis.  My LFS is using a two stage system when he is making water for his tank. He does not use the reverse osmosis stage to filter out his water - just the prefilter and carbon filter.  Is this adequate or should I do the reverse osmosis to ensure the water is clear of any contaminants.  <Depends one what those contaminants are - how is the quality of your tap water? Could be particle and carbon filtration are all you need.>  How does this compare to a DI ( which I am assuming is a deionizer).  <Each is a type of filtration so each is particularly good at filtering out certain 'stuff'.>  The only deionizer I've seen in my area is TapPure which makes about 25 gallons before the cartridge is replaced.  <Not very economical.>  What do you suggest?  <Well, in RO/DI, the deionizer is the last stage in the filter so the resins last a little longer, but is the nature of all cartridges. Unless your tap water is bunk, you can probably just use that. Please read here:  http://www.wetwebmedia.com/water4maruse.htm > Thanking you in advance  Vito <Cheers, J -- >

- RO/DI and Water Purification - Hi, I've been reading all of your articles on water purification and it appears it would be wise to invest in an RO/DI unit. <Really depends on the quality of your source water, but for the most part these are a worthwhile investment.> I've been looking online at the Kent, Captive Purity and Spectrapure units.  The price of the high end SpectraPure unit is about twice that of the other two.  Is there any reason for the large gap? <To be honest, I don't know why the large price gap - could be the parts or cartridges they use. Am aware of high-volume systems that are quite pricey, but worth it if you need the output.> Also, can you recommend a good unit. <I'd go with the Captive Purity [which is what I own] or the Spectrapure just because I have an allergic reaction to Kent products. But really for the most part, almost all RO/DI units are created equal - same parts, same cartridges.> I don't mind paying a little more as long as I only buy it once. Thanks for your feedback -Brent <Cheers, J -- >

- RO Selection - I'm in the market for a r/o filtration system.  Do you have any you recommend? <They are really are pretty much the same. Find a unit that fits your price range and you'll do just fine. Cheers, J -- >

RO (devices for sale) Bob, I saw some references to RO in your forums/posts and wanted to offer my systems as an option. There are a lot of systems out there, some good some bad, but you never know what you're getting. My systems are made in the US with US components (no third tier foreign copies) and are FDA/NSF approved. The price is right and I have addressed all the normal concerns of RO: low pressure in tank, wasting too much water, slow production and limited capacity (small tank that isn't full). My systems are a minimum of 5 stages (4 stage and lower increase membrane fouling and have lower quality water) produce 50 gpd - five times faster than most RO systems (they are rated 100 gpd but that isn't accurate, although most suppliers go with the rated gpd) they waste 400% less water than other systems, fill the tank to 90% of line pressure (competitors go up to 70% - 60psi X 70%=42psi in the tank) and produce great water and only cost $700 if installed by the customer. <Very nice specifications, but the price a bit steep for the vast majority of pet-fish enthusiasts... however there is (IMO of course) a percentage of "higher end" folks (maybe a handful %) that would pay for such units> I generally sell large upgraded tanks to aquarium owners 10 - 50 gal or more. I have larger systems as well from 50 gpd to 10,000 gpd. I also sell a distiller/ozonator that cleans up several problems in fish tanks. Email me and I'll send you a sample of the water you can put in a tank that has problems and you'll see the difference. <No need/desire to send sample. I don't have equipment for testing such. Please send along your URL and we'll post it on WWM and give you what feedback we can to assist you in marketing your products. Bob Fenner> Thanks, Tim Krusemark Aquatek Water Treatment

- RO & Circulation Questions - Jason, <Good n'you?> Thank you very much for your response. <My pleasure.> It helped greatly. <Even better!> As it turns out, I found that the HD/Lowe's RO units are more costly than ones I can order on line from aquarium supply stores (I think due to the mandatory storage tanks and fancy chrome faucets that come with them).  As a result, I will wind up getting a 25 G model that should easily allow me to follow your advice on filling the new tank over a few days. I hate to be a pest, but I have 1 additional question (for now ;-)).  I just read Anthony's article "water flow, how much is enough", and what I'm unclear on, is when he says that most keepers of corals advocate 10-20 times the tank volume per hour, is this the total between everything including power heads? <Yes.> Or does that 10-20 spec just take the main system pump into account? <Total system circulation, including powerheads.> Thanks again for your advice. Eric <Cheers, J -- >

Cheap RO/DI... Found this link on another board gang, for those looking for RO units, these prices seem very attractive, don't know if anyone has used these guys but thought I'd pass it along....riot..... http://www.airwaterice.com/Retail%20Price%20List.htm <Very reasonable pricing. Thank you for sending this along. Bob Fenner>

- RO/DI Filters - Hi Mr. Calfo and  Bob and Steve and the rest, <Greetings, JasonC here...> I want to buy me an ro/di unit(4 stage). I am not familiarized w/ them that much, although I have done my homework and I learned that they are 3 different types of membranes: TFC, CTA, and Hi-S, the latest one being of the highest quality. I am now wondering if there's a substantial difference on water quality if I buy a unit that comes w/ TFC instead of the HI-S ones, remember that I will have a 4 stage. <I don't think so in a 4 stage unit... the DI would get most everything the RO missed, which wouldn't be much. In my opinion, the biggest differentiator in RO/DI units is the flow rate - total gallons per day produced.> I want to know if it makes a difference who makes the membranes?? (film tech vs. Kent) <Probably not... I'd be willing to bet Kent doesn't manufacture their own RO membranes but simply repackages them.> Is the membrane size standard from different brands? <That I don't know.> what about the canister size?? are they standard?? <Seem to be.> and what If I get a unit that comes w/ TFC can I use them and then replace them w/HI-S? <Yes.> can I use membranes that are for a 35gpd unit into a 36gpd?? <Yes.> I want to support my LFS and he offered me a 4 stage 36gpd for $165.00, TFC membranes (brand new), but do you think I should go ahead and buy another one? <Why not go for it and test the outgoing water - I'm sure it will be 'good enough' as they say.> (have suggestions??). I want to use the unit for top off and water changes for my 75g full blown mixed reef. Are the pre-filters sediment and such) and the block carbon filters necessary/do I see a difference?? <If you want the RO membrane to last any period of time, they are quite necessary.> I'm sorry... lots of questions I know! Thank you so much for any help you can give me though... I just want the best for my Tank!! YOUR WEB SITE IS THE ONLY ONE !!(the best) <Cheers, J -- >

Water filters Bob or Anthony: I want to know what your opinion is on Poly-Bio Marines KOLD STER-IL water filter. <outstanding> There sales pitch make it sound better than R-O units in many ways. <agreed> Will these units give me very good quality water? <some of the purest> Currently use Kati and Ani but recharging is a pain. <heehee... a deionizer is my strong preference for minimizing water waste actually> Any info or input would be much appreciated. Thank you very much: Pat <either produce very pure water. Best regards! Anthony>

- Using RO/DI - Hi how are you today? <I am well, thanks for asking.> I am setting up a 55 gal. reef tank and question the need for a RO or RO/DI unit. I just received a copy of the water quality in my town. It list some 10 substances and the highest detected levels of each from 1999 thru 2001. They are as follows. Fluoride 1.4 ppm Nitrate 4.9 ppm Alpha Emitters 12.0+/-4.0 pCi/I Copper 1,000 ppb Lead 7 ppb Bromodichloro-methane 0.8ppb Chloroform 3.4 ppb Sodium 25.9 ppm Sulfate 36.9 ppm P-Dicholro-bensine 0.4 ppb (ppm = parts per million  ppb= parts per billion) Looking at these findings do you think an RO or RO/DI unit is advisable or necessary? <I would use it.> If so what are your thoughts on the KENT HI-S 60GPD MAXIMA RO/DI unit as I can get this unit at a very good price at Champion lighting. <Most all RO/DI units are created equal, with the price differentiator being the output.> Thanks as always Dennis <Cheers, J -- >

- RO/DI at Home Depot - Am I missing something? I have been reading all the FAQ re. RO system an keep reading about the simple and cheep RO system at home Depot. I have gone to there site an find the GE Reverse Osmosis Filtration System Model: #GXRV10ABL to be the only RO system they have. It produces 10 gal per. day and cost $239.00 I can purchase the KENT HI-S 60GPD MAXIMA RO/DI unit as noted below for $206.00 and it does 60 gal. per. day and also has the DI unit and HI-S membrane. What am I missing? <Probably nothing - not all Home Depots are merchandised the same. The unit mentioned is sold in some instances as a "Bare Bones" RO, but not always at Home Depot.> Very Confused <No need to be.> Dennis <Cheers, J -- >

Deionization Unit.. Where can they be bought? Hello! I am putting together a 120G reef system and have not decided on what water purification to employ. I live in a condo and have a 1/2" water pipe at the location of the tank but not a drain. I don't like the idea of the waste water produced by RO/DI units as I pay for my water usage. I have been reading your Q&A's and see references to a two column DI unit but can't locate information on units available commercially and at what cost, nor any info on flow rate, resin consumption etc. Would you have any links to suppliers, info on costs & usage? <See our sponsors, Foster and Smith for Kati/Ani systems.> Assuming I can locate a DI unit that isn't cost prohibitive and can produce sufficient gallons per day am I better served with this system than to locate a RO/DI remote from the tank and transport the water as needed? The nearest sink to the tank is approx 12-15' away. <This depends on your source water and it's content. Both produce water stored in a container for later use, pumps move both easily.> I also read recently a write-up on a Permeate Pump which significantly reduces the amount of waste water produced from the RO/Di units. Have you any experience with this unit and any guidance to share. <RO units require optimum pressure and temperature to get the highest production from the RO membrane, this pump simply increases the water pressure to increase product vs. waste. If RO is your choice, you must factor temp/pressure/efficiency to determine likely output, which in most cases is far less than the advertised rated output.> One more question, the waste water from the RO/DI unit, does it drain under pressure. I ask as I might consider drilling a small hole through the outside wall to drain the waste to the front garden, although this could be problematic in the winter months. Many thanks in advance for your help. <Yes. Low pressure, but pressure. You may want to locate it permanently at a known drain and install a drain saddle to drain into the house system. Buy the float valve set-up to avoid Marital and water disaster with either.  Test your water completely to buy the right unit.  Have fun!  Craig>

Will RO work?  Is it worth it? Hi guys, After two and a half months with my new 55 gallon tank I have still not purchased fish yet due to a nuisance algae, (mostly brown slime string algae on substrate and live rock ) problem I am dealing with. To trace the source of the problem I started with the source water as that is the only thing in my tank plus the live rock. I took my aquarium water sample (used TWP deionizer cartridge filtered) to a local water testing consultant (who really knows his water !!) who used sophisticated accurate testing and this is the results:     Phosphates (tested for total phosphate) .22 ppm     Silica              .80 ppm     Nitrate     1.90 ppm I am working towards upgrading my protein skimmer as my Bak pak 2 that hangs off the side of my sump isn't really efficient. <About the limit of this skimmer unless adjusted optimally, w/sump more volume than 55 gal. Look into Aqua-C Urchin Pro or Remora Pro. Add to Bak Pak.> I am extremely nervous about going the RO route, not because of the waste, as I am leaning towards the quality Kold Steril unit but of the big expense ( approx $300 for the system and then needing a plumber to install unit under my sink). <Once you provide for the type of unit needed to remove silicates (phosphate and nitrate is a bit easier) there is very little substantive difference between RO/DI units (I suggest the DI unit downstream of the RO) besides price and service should you need it which is unlikely. Most of the component parts (filter and membrane housings, etc.) are interchangeable as are many of the after market/replacement micron and carbon block filters. RO's  don't produce as much water below 70-75 F water and <80psi (or manufacturer stated pressure) but this is simply factored into sizing the unit larger to accommodate your water needs or investing in a booster pump. You might start in the laundry room (stay away from bleach, soaps, etc) and push the drain line into the washing machine drain, hook the inlet up with a "Y" on the washer cold water valve, and route the product water into a Rubbermaid can on wheels with a shut-off valve so you don't flood the wife's laundry room. That last part is the most important. Make it easy to get to.> Are these systems worth the cost and hassle ???  I absolutely do not mind spending the money if it will really work to rid me of this nuisance algae. I know I cannot be 100 % free of it but my tank now is really unattractive. <Yes, they remove the source of these problems. (and tasty, ultra-pure water.> I am also worried about the ease of operation of these units (water temp needing to be just right and flow rate just right or it won't work etc). <See above, it will work, just not produce as much as the rated amount. You need to factor this into sizing the unit. If you need 30 gallons per day, best to get a 60gpd unit to factor in temp and pressure being less than optimal.>     How is your experience been with these RO units and their ability to solve nuisance algae problems ???? <These are a good investment. Shop around at our sponsors!  Craig>

- RO vs. distilled water - <Greetings, JasonC here...> I'm sure you cringed when you saw the subject line, because I know this issue has been talked about.  However, I'm still unclear as to which option is better.  Is price the only issue, or are there other things to consider? <Well, my own limited experience with home water distillers is that their production is limited and they take a lot of electricity. You would be limited to perhaps two or three gallons per day. Now I'm sure there are more modern units that can improve on that slightly, but you sill have to boil water and cool it back down to distill it... so all in all the process is rather inefficient. An RO unit in the price range you mention would likely produce 35-60 GPD.> I can buy a used water distiller for $300 Canadian, which I believe is probably not too different than what I could get an RO unit for.  So, price being equal, which is the better option for my reef tank? <RO/DI.> Thanks, Steve <Cheers, J -- >

Choosing RO/DI - Chlorine vs. Chloramine Hello & Good Day, Everyday reader of your Daily FAQ.  I don't really have a question per se, just wanting to pass along some information for people researching the various RO or RO/DI units for purchase. <Okay> Once you've decided on the Make/Model of the unit for you and your fishes and prior to placing the order, call your local Public Works and ask a simple question; Are you using Chlorine or Chloramines for water purification? <Almost all United States municipalities use chloramine> Knowing the answer, and passing this information along to your vendor of choice will ensure you get the proper Carbon Filtering Media. Case in Point - I purchased a 4-Stage RO/DI unit from Aquatic Reefs back in February. Not knowing the answer to the Chlorine/Chloramine question, not knowing there was a difference and not being told beforehand of the importance of the difference I placed my order. Unit arrived and I, excited as a kid at Christmas hooked it up and proceeded to make RO/DI unit water for my tank. Fast-forward to Apr 16th. RO/DI water now measures 45+ TDS. I think to myself -Wow- I've only put approx 125gals through this rig and I already need to replace a filter. So I call Aquatic Reefs. Troubleshooting the now high output and short lifespan of the filtering media led to the realization that my local Public Works is using Chloramine for purification. My original setup was shipped with Filter Media for stripping out Chlorine. The Chloramine has basically 'cooked' the Filter Media, greatly reducing its lifespan. So, in closing, take the extra few minutes to research if you'll need the Filter Media for stripping Chlorine or for stripping Chloramine. Then, be sure to pass the info along to the vendor. I hope this little bit of info is able to help someone out. I'd also like to do a quick shout-out to John at Aquatic Reef Systems. Both he and the company continue to earn High Marks! Many Thanks, Scott <Thank you for sending this along. Bob Fenner>

Water Pre-Treatment... I'm trying to learn as much as possible about keeping a reef tank before I actually invest in one (or two...three...) and risk killing the fish/inverts, wasting money, and making my wife cranky. <Ya don't want to do that! Scott F. feeling for you today!> The biggest problem I foresee is the issue of initial tap water filtration.  The only real LFS in this area stinks (literally, on some days).  They do sell RO but walking by their tanks is a dismal experience and I don't/can't trust them to provide me with quality water when almost half of their fish are bobbing at the top of the tank, bloated, w/ eyes eaten out <shudder>. <Lovely imagery! Scott F. with you tonight, gagging at his keyboard...!> Determined to be as self-reliant as possible when it comes to handling my own water I set about searching for info on the Web and came across WWM.  After staring at different RO/DI units for the past week and trying to stave off the sensation of vertigo I get when considering all my options I came across the rofaqs.htm page in which you say, "This is a very good product", referring to the Kold Ster-il purifier by Poly-Bio Marine. From my (ignorant) perspective it looks great...says it can filter up to 5,000 gallon, leaves desirable minerals in the water, etc. <It really is an excellent product> Are there any gotcha's that I may not be aware of...? Or would this unit be all I need to turn my nasty tap water into something more suitable for sustaining marine life? <Well, it does leave minerals in the water, which is not a bad thing...There is no waste water produced with this system. The Kold Ster-il can be enhanced to extract phosphates and silicates by utilizing and additional filter media in the second stage of the unit. Use of RO/or DI is optional, and possibly unnecessary if you use the Kold Ster-il in this fashion> The official manufacture's website mentions using it in tandem w/ a RO filter.  Is this needed in most cases?  A big question I'd like answered is whether it produces "waste water" like RO units do (somewhat of a disqualifying factor for me...can't imagine what I'd do w/ all of it).  Could the water that comes out of it simply be added after 12hrs aeration/buffer/salt mix...or is there something else that would have to be done? <As mentioned above- you could augment the system with an RO unit- but, in all likelihood, the Kold Ster- il will do the job quite well...just prep the water liked you mentioned above, and you will be quite happy with it.> In the end I'm going to try to produce enough water for water changes/top off on a 80G Reef, 30G Planted FW, and 12 Mini/Nano Reef. I am guessing based on the condition of my FW tank that my phosphates are relatively high.  It would also seem, according to a cheap test kit and opaque water spots on my tank, that I have "liquid rock" on tap (Southern CA). Am I on the right path at all?...or am I completely buggered? Any info/guidance would be immensely appreciated, Jason M. Wood <Sounds like you're on the right track to me! Good luck with your set up! Regards, Scott F>

R/O question Hey, I stumbled onto your site the other day after searching for discus online. let me say that you have a great site with a lot of helpful info. Let me give you a quick run down of my situation. I bought a 46 bowfront tank second hand and it came with 10 small brown and one larger blue/green discus. After a 2 hour drive and the setup 2 of the smalls died (3 months ago) so I am now left with 8 brown (orange is more like it) and the larger fish. Before and especially after looking at your website, I decided on a planted tank. So far I have regular plain somewhat med/small gravel in there with some swords which are starting to settle in. I just purchased a 110 watt lighting top so the plants should start doing better (also have a DIY in there).  Here is the problem... The tap water in my area is hard with about 8ph. The fish are doing ok in it, but obviously could be doing better in softer/lower ph water. <You are correct> One of the options I currently have is an R/O system. It would be used for drinking water as well as the tank. <Good> Since I have never had an R/O system before, this is where the confusion begins.  <I am a BIG fan of these units...> I have looked through different stores as well as different sites for ideas but have yet to find a system I am happy with (since I don't really know what to look for) and the articles on krib are from 92 and around that time. I found a system on Costco. COM which doesn't waste any water (at least it's their claim) which leads me to believe that all the others do. this system would run about 310.00 and it's their only system. Costco's RO Unit.  On EBay I found a bunch of systems for $100-$200.  I know you are seriously busy and said to check out your faq and the rest of the site (which I did and did not find an answer to this). If you can point me in the right direction, I would most certainly appreciate it. Thanks, David <No worries... David, there are only slight "variations" in these units... akin to "super" or "regular" gasoline... All these units "will do"... the amount of water actually "wasted" (vented, more solute laden) is actually miniscule... folks lose more water from leaks... long showers... a concern in some places... and a possibility to build.... perhaps a pond! To vent this water to... and in turn to landscape irrigation... Do take a read through the many RO FAQs filed here: http://www.wetwebmedia.com/h2opurifiers.htm the blue, linked files at top... for more opinion, input. Bob Fenner

- RO/DI Units - I've used your site several times for info and learned a lot. I'm looking to buy a RO/DI unit for my 155 tank but I'm a little confused as to the following; 1. Is RO unit preferred over RO/DI or the opposite?  <Depends on the source water. I own an RO/DI unit but my current water doesn't need the DI so I run it without that cartridge. Also, RO/DI water typically needs to be reconstituted before adding salt.> 2. Any preference over the best type of unit?  <No... all are built pretty much with the same parts.> 3. Bob has mentioned that he has used units bought from Home Depot... I'm thinking of doing the same... what are the specifications I have to look for?  <The GPD [gallons per day] that you require; not much more.> Nilesh <Cheers, J -- > 

RO systems  Are average RO systems for home well water purification (i.e., under-sink models) adequate for marine aquarium use? I'm referring to the name brand systems, like Kenmore, Whirlpool, and GE. I also hear that most home systems are not suitable for well water because they don't have the antibacterial substance in the RO membrane unit, which can cause the membrane to clog in as little as 2-3 weeks. What have you heard about this?  <The RO's for home use are designed to work with chlorinated water. The chlorine in the water prevents bacterial buildup on the membrane. Keep in mind that a good RO system usually pushes water through a 1 to 5 micron cartridge before it enters the membrane. There are units available for unchlorinated water supplies. Check with Drs. Foster & Smith or Premium Aquatics as to availability. James (Salty Dog)>

Reverse Osmosis Real quick one tonight. I am looking at purchasing a new RO and wanted to know your opinion on the Captive Purity Brand. <I have no first hand knowledge, but a lot of people on the message boards seem happy with them. I use and sell the SpectraPure line.> What you know or have heard? <See above> The three I am looking at are the Kent Marine Hi-S, Captive Purity, and SpectraPure. <I have always been happy with SpectraPure.> Thanks, Bryan <You are welcome. -Steven Pro>

RO filters... Hello! I was reading through some FAQ's about RO/DI filters and I'm stumped again. I saw that your response to an RO filter was that it wasted obscene amounts of water, <Probably Anthony. He is much more sensitive about them then Bob or I.> so if I wanted to purchase a water purifier of sorts should I go just for a DI filter instead of an RO or an RO/DI filter? <There is no difference in waste water between a RO or a RO/DI filter. DI alone, though, do not waste any water, that is until your recharge them, but that amount is still very small in comparison.> I have heard so much raving about these filters and it seems like a brilliant idea and much healthier for my fish so I thought I'd rig up the classic rubber-maid trash can and get started, but I wasn't sure what was the suggestible route to take. <I use a Kati-Ani DI unit and love it, but the chemicals to recharge an rather nasty, so for most people I recommend RO units.> Also, I have massive space constraints (I live in a dorm) and while I could fit a trash can system in my room it's not easily hidden and it would take up a fair amount of space, is there any other option? <If your tank is small, 30 gallons or less, an Aquarium Pharmaceuticals Tapwater Purifier maybe a good option. The unit is small and cheap, but the cartridges must be replaced. This can get expensive if you need a lot of water. That is why I recommend them for relatively small tanks, only. By the way, this unit is a mixed resin DI.> I don't mind sacrificing a bit of space or beauty for my fish, but I just thought I'd ask :-) Thanks again for all your time! Sincerely, Rachael <You are welcome. -Steven Pro>

Salt Pellet De-Ionizer Thank you for your prompt responses.  <our pleasure indeed> Yes, I know I need to do something quick. I have been trying to surf and learn.  <excellent... your best defense is always being an educated consumer> Yes, I hang my head in shame.  <no need for that... we are all and always learning> I am poisoning my fishes and my self with my salt-pellet-fed water softener. Sears Kenmore, no less. (sigh). I never knew it was bad, health-wise. Are you a doctor?  <no... not at all, my friend. And the softer use for people is not really a problem (I exaggerate <G>)... some folks have ascribed concern and complications for the excessive consumption of these chlorides.<Actually sodium. RMF> Ultimately... it simply isn't as good of a choice (with regard for purity) as an Reverse Osmosis or Deionizer for the whole house and fishes. The chloride for the fishes, now, is another story altogether. Prolonged use of salt recharged softeners has demonstrated clear symptoms of enlargement of the olfactory pores on the heads of cichlids (resembles hole in the head disease). It can be induced in less than a year when using this water (salt recharged/chloride rich). Other fishes are surely stressed too. The first thing we need to do is assess which if any fishes in your tank need soft water. Then decide if its worth the effort or perhaps you can simply enjoy harder water fishes instead (some cichlids, most all livebearers, etc)> Again, the Aquaclear 150 is my only filter, other than the fine and massive surface area of the gravel itself,  <which is really little help with such a big fish load... helpful, but not enough and easily disturbed> and all those nice long roots of the water hyacinths and milfoil or whatever it is, which doubtless also harbor those nice bacteria, and are the only reason my ammonia is 0 so far.  <agreed and wonderful... the plants are an enormously effective filter. Your tank would literally crash within days without them.> And of course, I have been cleaning the gravel and replacing about 2 gallons every weekend. I wasn't clear on your answer about the undergravel filter. Are you saying you prefer a "large canister filter or wet dry trickle filter" to a larger Aquaclear AND an undergravel filter?  <the AquaClear with either the canister or the wet dry. The UG filter is too hard to install at this point and not as good of a filter> I am not familiar with canisters or wet dry trickles, but I did see some on eBay. I will try to research and read what they are.  <definitely look into some good reference books too please. Much is explained therein. > What size do I want? I think I would prefer an undergravel if that would do the trick, as it sounds like a "set it and forget it" type of thing...easier?  <an undergravel filter is in fact more maintenance than a W/D or a canister filter. Gravel siphoning is necessary and laborious> But I want to do whatever my little finny friends need. Just guide me, oh guru of the water world. Humbly, Lisa <you are on the right track... do keep learning and growing. For know... cultivate those plants with TLC, do regular water changes (small weekly ones are best), do not buy any more fish, please do buy some good reference books, and enjoy your hobby :) Anthony>

Reverse Osmosis Filters Hello Crew just bothering you guys yet again. <No bother!> I'm thinking of purchasing an RO filter and wanted to see if you could tell me what the advantages and disadvantages are to using RO water in your tank and if you would recommend an RO system over another. <The answer to both questions starts with testing your source water and then purchasing a unit that removes any unwanted elements and produces the volume of water you need at a given temperature and pressure. The reference to "stages" usually refers to the number of filtration modules the water may pass through. This usually starts with a half or one micron filter, a carbon block filter, a RO membrane for the type of water you have, and perhaps a deionization stage to remove silicates or elements the RO membrane can't remove.> Looking around I ran into these different systems but I don't quite know how they differ one from the other (except that one is more expensive then the other). Two Stage SP Reverse Osmosis Two Stage CHP Reverse Osmosis Three Stage Reverse Osmosis Any help would be appreciated.  Thanks. <The best way is to start with your water and needs, and then proceed from there. Many questions can be answered this way without marketing confusion. Check out the equipment threads at: http://wetwebfotos.com/talk/index.jsp   Also look into Kati/Ani units at our WetWebMedia.com sponsors.  Craig>

RO, Kati/Ani Unit Good Evening Crew, I'll try to keep it brief this evening for ya'll. I've used RO water religiously since I set my 55 gallon tank up 2 years ago (FOWLR). However, I'm tired of the 30 minute drive that it takes to get to the LFS. Thinking about getting a Kati/Ani unit but can't find enough information about the two. <First off, go to www.WetWebMedia.com and type Kati Ani into the Google search engine. You should find plenty of information that way.> What's the difference, and do I need both? <You do not need a RO and a DI, but you do need both the Kati and the Ani portion of a deionizer.> Dr.'s F&S have a Kati 2 and Ani 2. Would this do? <Yep> R/O wastes way to much water and I don't want to be the wanker responsible for draining the local reservoir dry. Alright, one more thing, what kinda chemicals are used to regenerate the units? <Muriatic acid (HCl) and Lye (NaOH2) The last thing I need in my kitchen is a Meth lab. The one in the basement is more than enough (just kiddin'!). Thank you so much for your time, knowledge, and love for the hobby/lifestyle. Rob     <You are welcome. -Steven Pro>

Improving Tap Water Hi guys, <Hi there! Scott F. here this evening!> As I've stated in my previous emails, I am slowly converting from a FO to a reef tank. Right now I cannot afford an RO/DI unit.  I was wondering if a product like Seachem's Phosguard would be enough to get me by. <Seachem makes fine products, but I don't think you can rely on a phosphate-removing resin alone to deal with phosphate on a continuous basis. I think that the best way to eliminate phosphate from aquariums is to do frequent, small water changes (like 5% twice a week). Much phosphate is regularly deposited in the aquarium through foods, so careful feeding is another thing you can do to reduce phosphate buildup in your tank. Perhaps you can treat your makeup source water with the phosphate removing resin before you mix the salt.> I live in New York City.  Are there any other parameters (besides phosphates/silicates) that I should be concerned with in a city water supply? <Many, many things, such as nitrate, heavy metals, chloramines, etc. A good grade of activated carbon in an inside box filter, placed in your makeup water container can help remove some of them. Using a product like PolyFilter in your system on a regular basis can remove a lot of detrimental substances from the water, too.> As far as chlorine goes, do the salt mixes on the market like Coralife and Instant Ocean contain dechlorinators, or should I also be using a product like Amquel? <I am not aware of any salt mixes that contain dechlorinating substances, so I'd use one of the products you mentioned, in addition to aging, filtering, and aerating the makeup water before its use> If/when I can afford an RO/DI unit, can you recommend an efficient, low cost unit.  Also, what product should then be used to replace what the RO/DI removes from the water? <There are a number of good units out there on the market available to hobbyists. I'd recommend a DI unit instead of an R/O for its efficiency and lack of excessive waste water production. Do check our advertisers on the wetwebmedia.com site for the manufacturers and models that they carry> Thanks again, Adam <And thank you, Adam, for stopping by!>

RO Water Hello once again guys.  David D will be thrilled to hear a new LFS has opened up 15 minutes from my house....it is INTENSE, very cool. <Allriiiiiiiight!!!> Also, I found out this week about Inland Aquatics in Terre Haute, IN....I live in Indianapolis.  Went out there....they say it is the world's largest reef replica....it also is super intense, you guys have to see it sometime.  Huge warehouse.   <Oh man oh man! I would love to see it!> So anyways, I have a new supplier.  Second, an Aqua C Remora Pro is en route to my place as I write this...question...is it worth leaving the SeaClone 150 running as well as the Remora Pro, since the Remora Pro isn't quite big enough for my 120gal? <Does the SeaClone pull nasty stuff out of the water? If it does, leave it. At any rate, it won't hurt anything it just might not help much> Finally, I have decided that I'm going to start RO/DI for my water changes....Indy water is awful, I hate to think what could be getting to my fishes.   <You should see the test for the Las Vegas water supply...> So, here's the main question:  Are they all pretty much the same, or are some units better than others?   <Yep...not much different. They all use cartridges that do the job of filtering. Personally, I haul water from a public RO/DI station that is near our local supermarket. I do this because municipal water is expensive in Vegas and believe it or not...Over the years I've grown to enjoy the weekly water outing. If you really don't want the hassle of hauling, consider skipping RO and use a DI unit only. I read emails all the time about how much waste water is produced by the RO process. One email said the ratio of waste to water on her RO unit was 10 gallons to 1 gallon! That's too much for my taste. The DI process produces no waste water...> CTA, Hi-S, etc, etc...?   <Again...not much different. More stations mean more filtering but you really don't need to spend a lot of money on this item> I really only need about 3 GPD, my water supply is free of charge, and I'm fairly sure I want to go with the Kent brand RO/DI filters.   <Kent will be okay. By the way, the units that are sold at Home Depot and other places are more permanent than a fishy unit but other than that, they are basically the same. I would check for a no-name-brand unit at one of these warehouse stores. In your case, it might would be better to just install a permanent unit on your kitchen water faucet. Then you too could have the benefits of drinking RO/DI water!> Hate to ask for brand endorsements, but I need to make sure I do this right.  Thanks. <You're welcome! I wouldn't spend a lot of time worrying about brands on this item. Look for what the unit removes form the water (metals, nitrate, etc)...be sure the things that it removes are what you want to remove and then check out what the waste to water produced ratio is...pick a unit with numbers that you can live with. David Dowless> Matt

RO filtration or Carbon Filtration ? Hello WWM crew, I had yet another question regarding RO/DI and Carbon filters. I've been reading on how RO filters waste a lot of water but will make your water 99% pure. On the other hand, I heard that carbon filters will not waste water and will make your water 90% pure. Is this true? <RO units do waste water and probably make 99% pure water. I do not know how much a simple carbon filter could extract, but find it hard to believe it would approach 90%.> Would it be wise for me to invest in a dual stage carbon filter or would it still leave a lot of impurities and be a waste of money? <If you want pure water and no waste, you should consider a DI unit. We have written much on them on www.WetWebMedia.com. Use the search terms Kati Ani or Deionization and I am sure you will find plenty.> Thanks <You are welcome. -Steven Pro>

Confusion over RO vs. RO/DI vs. DI Hi, I hope you can help me out with some of the confusion I'm having over RO/DI. That phrase (RO/DI) is my problem. When reference is made to using them in a marine aquarium, are you referring to one OR the other or one AND the other together? <A RO/DI unit has both a RO membrane and a DI canister.> What I see for sale is mostly labeled RO units. <They are the most popular, RO only. RO/DI are for truly awful source water and/or to make very pure product water.> I am looking to remove primarily phosphates from my tap water. Which is more effective for this, RO or DI? <Either will be fine.> Will one remove some phosphates and the other make up the difference? <Ro/DI units are very good for removing silicates.> If the RO unit is the better choice, are the TFC units worth the price difference over the CTAs? <Yes, you want a real RO unit, not the "bare bones" types.> I'm anxious to get rid of the daily scraping of my aquarium glass! <This may be part of the solution, but not all of it. Do review your other sources of nutrients and your nutrient export processes.> There was an answer on the forum to a reader concerned about lowering phosphates that said "I recommend a DI unit instead of an RO for its efficiency and lack of excessive waste water production". Was there an ecological consideration or a reference to it doing a better job with phosphates? <Likely Anthony and an ecological reference.> Thanks in advance for any help you can provide. <You are welcome. -Steven Pro>

Reverse Osmosis Systems Hello, <Hi Helene> My husband is looking into a reverse osmosis system for his 90 gal marine aquarium (has fish and live rock).  Can you recommend a specific one that is reputable and where to purchase (either online or store).  We live in Maryland. <Am sure there are some specific brands that the other folks here might well specifically recommend. I am of the opinion that most all units available are within a few percentage points similar (like brands of gasoline) and consistent with this perspective just buy/use "home improvement warehouse" models... that incorporate an in-line pre-filter... and either just the "little pressurized storage" unit included or have the device dump the finished water into a dedicated trash-can... and pump it from there. Some aquarists prefer the Deionized or combo. R.O./D.I. product... and if you're going to be using the R.O. much, there is the "waste" water volume to consider using for other purposes. Please see here re more input re these matters: http://www.wetwebmedia.com/rofaqs.htm and the linked FAQs files beyond. Bob Fenner> Thanks very much, Helene

RO/DI question 12/1/04 Hello All: I found a manufacturer of RO/DI units in your FAQ's and now I cannot.  Can you possibly give me a list of several recommended models/manufacturers to jog the ol' gray matter?  Thanks for the help. Scott <Other than being sure that you get a TFC (Thin Film Composite) membrane, I would suggest shopping price.  Most membranes are made by the same few manufacturers and are of good quality.  Most aquarium brands come at a premium price, but may have better rinsed carbon cartridges (rinsing removes the phosphate introduced in the manufacturing process).  I have found many good deals on EBay as well as small independent companies that cater to aquarium folks.  A Google search should keep you busy shopping for hours.  Best Regards.  AdamC.>

SpectraPure DI unit model suggestion 11/29/04 I have been considering purchasing a DI unit to produce high quality water for my marine aquarium for some time now and have sifted through the RO/DI facts on your website to pick a brand.  I noticed Anthony endorsed SpectraPure DI units on numerous occasions so I think this is the brand I am going to purchase.   <Hmmm... I don't recall SpectraPure so much as Kati Ani brand FWIW> I am confused as to what to by as after my water softener to remove some of the extreme hardness my water contains, this will be my sole water purification as I am not going to get an RO unit. The SpectraPure website recommends the two stage D-CL-AR-2-10 system for water containing chloramines and recommends the two stage D-CL-Sil-2-10 for removal of Silicates/Phosphates/Nitrates, and CO2.  As I want  to use the unit to dechlorinate my water in addition to removal of the Silicates/Phosphates/Nitrates, could you tell me what to buy to accomplish this?   <Really not sure for whole house use... do rely on the mfg rec.s> Will the two stage D-CL-Sil-2-10 unit also dechlorinate the water? And do I have to buy other components such as a 1 micron filter and an activated carbon filter to add on to the two stage D-CL-Sil-2-10 for it to be totally self sufficient?  And my final question, does the SpectraPure units hook directly to my kitchen faucet or do I need some type of adapter? Thank you for the advice. Ray <These questions are really best for the manufacturer or dealer, my friend. I can only speak to aquarium units. Anthony> Mixed-Bed versus Rechargeable Deionization 1/11/05 I have two questions about deionization and determining what purification system is appropriate for my tap water. (1) If rechargeability is not a factor, wouldn't mixed-bed deionization be more advantageous due to its ability to produce purer water? <not necessarily true (usually not in fact). It depends wholly on the resin, and there are many kinds to be had. generally the rechargeable ones are better quality than the disposable hobby use satchels> A representative of Kent Marine stated that a mixed bed deionizer will produce water with 18-megaohm resistivity compared to rechargeable deionizers that produce water with only 2-megaohm resistivity.   <perhaps true of some low grade resin he was comparing to for marketing purposes. I assure you this is not the case for all others or even most rechargeables> I notice that SpectraPure uses mixed-bed resins in its "Ultimate" DI system that is also capable of producing water with 18-megaohm resistivity. <its indeed more profitable to keep selling disposable resin rather than rechargeable one time only ;)) Many chemophobics, such as myself, shy away from the caustic chemicals used to recharge resins and would simply replace depleted resins in any case. <Yikes! What a waste of resources! And the recharge chemicals mix to form inert (literally drinkable as demonstrated by chem lab professionals with carefully measured molar concentrations). You are off the mark here my friend... wasting is not conscientious, re-using is IMO> (2) Where can I take my tap water to be tested to determine if prefiltration & deionization alone is sufficient? <many (water) testing labs online... do a google search for one that appeals to you (price. service, etc). Maybe ask your local water authority for their official analysis> I'd like to forego wasteful reverse osmosis and use prefiltration with deionization if the quality of my tap water is good enough.  I live in Colorado and am deeply suspicious of my "Rocky Mountain spring water."  Don't ask me about Coors beer--I've smelled the water at the brewery. Regards, Paul. <have no fear of the two column deionizers my friend... really efficient and environmentally friendly use/re-use. Anthony>

Pre-Filtration & Marine Salts 1/12/05 Anthony, <cheers> I very much appreciate your reasoned response to my questions regarding mixed-bed versus rechargeable deionization.  You have sold me on the concept of minimizing waste.   <always welcome my friend... I do aim to be sensible/practical> I'd like to pose two follow-up questions: (1) Which prefiltration assembly do you recommend for rechargeable 2-column deionization systems such as the KATI/ANI?  The only one I can find is the SpectraPure FA-PRE-0.5M-20 but I hope that you can direct me to more affordable prefiltration systems. <many possibilities here ... depending on the quality of your source water running through it. But, if your tap water is nothing out of the ordinary (like iron-rich well water requiring an extra metal sponge, or silicate-rich water needing chemical media, etc.) then I say just go to your local Home Depot or DIY store and get a cheap drinking water pre-filter unit. Two canisters cost (well under) $50. First stage will be 1 to 5 micron floss... second stage is simply good quality carbon. If you are really handy, you can DIY home make canisters out of PVC for even less money. If you want to get fancy, have two floss pre-filters (12 micron and a 5 micron to follow)... and better still... have Poly-filters (Poly Bio Marine) after the carbon stage> (2) What brands of marine salts will complement the Kold Ster-il filtration system?  Since the Kold Ster-il system does not filter certain minerals (calcium, magnesium, strontium, barium) and buffering compounds (carbonates, bicarbonates, hydroxides) from my pH 8.1 tap water, which marine salts contain lower amounts of these minerals and compounds? Regards, Paul. <without spending a fortune... I'll say that Tropic Marin is presently the best you can buy. I will add though that I generally like Instant Ocean's QC and affordability in my region and use it more often. Anthony>

Kati/Ani de-ionizer 1/25/05 I'm very interested in these units since they've been highly recommended and I'm not a fan of wasting water with RO. I searched through all the forums on the net and all the FAQs on this site and I've even called Dr. Fosters and Smith (since they seem to be the only e-tailer carrying them) but I'm not confident with the lack of information or answers I've received. So on to the experts (I hope I'm not wasting your time). <no worries> First question is, if I were to get the KATI 10 and ANI 10 (internal volume: about 785 cubic inches apiece) and use a carbon block pre-filter, about how long do you think the resins would last before regeneration is needed?  <impossible to say as it is dependent on the quality of your source water> Also, am I safe in assuming that if I were to get the ANI 5 which has about half the volume, the resin would last half as long?  <half as long before needing recharged, yes. Its just a matter of volume. The quality of resin is the same though> I've heard of people who have chlorine/chloramines in their water first aerating it overnight and then running it through the DI units to lengthen resin life. When you were operating yours, did you do this or did you just go straight from the tap? <a carbon prefilter takes care of this more conveniently> I've read that anion units in general produce water that has a high Ph. If I run the KATI first and the ANI last, what would you suspect the Ph would be (i.e. does the ANI unit produce a consistent ph or is it totally dependent on the input water)? <regardless of pH it will be unstable as it is demineralized... and as such, at risk of crashing (acidic). It needs to be buffered> And last, I've read that you recommend this unit a number of times. However, I've never really heard why. Is it due to quality craftsmanship, quality resins, ease of use, or other reasons?  <resin quality alone... the unit otherwise is awkward with tapered metric fittings> Thank you so much for the help with this and all the help that you have given others along the way. Your service is truly invaluable.  Derek <with kind regards, Anthony> 

Reverse Osmosis Hello Bob, Bryan again. <Hi Bryan, Steven here.> I'm going to order a RO unit, was looking at the Kent Marine's products, are these good units? They have a Hi-S (high silicate removal TFC membrane) is this for real or is it just a selling tactic to sell more expensive membranes? <No, they are a higher quality membrane. I am partial to the Spectrapure units. Their website is on the links page.> Now to my real question. From the F&Q's I think I understand that RO removes heavy metals, chlorine and even chloramine, nitrates, phosphates etc.. and other small particulates in water. This type of purification softens the water so an additive for pH and Alk must be added. I'm going with a FOWLR. Would a two part like B- ionic help (read that the added calcium will help w/ coralline algae growth on LR) or can using s/t like SeaBuffer or reef builder that sets pH and Alk in one step work. <I would use the SeaBuffer from Aquarium Systems. It is just as effective and a lot cheaper.> Thanks for all the great help. Bryan <We are all glad to help whenever possible. -Steven Pro>

RO Filtration Question So I purchased an RO system so that I can begin making my own salt water and top off water for my aquarium as suggested by Steven Pro. It wasn't that hard to install and I'm happy I did it. I purchased the Premier 5 stage system from Costco after hearing good things about it. The quality of the water is great, but it's slow. I went on their website and it seems like the system is only rated at 18 GPD. BUT... they also sell other replacement membranes that are anywhere from 25 GPD to 75GPD. Is the membrane really all that determines how much water gets produced by the filter? <Those ratings are for best case scenario. Things that effect performance are total dissolved solids in the water, line pressure, temperature, age of pre-filters, etc. -Steven Pro>

Salt Water Tank Questions Anthony...Thanks for the fast response the other day  <always welcome> and I love your website.  <thanks again... but its not my website <wink>... Bob Fenner is Santa, we are just the elves (no short jokes please!). In fact, it is a great collaborative effort of many seen and unseen folks. They will be sure to see this, my friend> Since the information that I have been seeing appears accurate I would like your opinion on some topics for which I keep getting conflicting opinions. I have been using distilled water in my 105 gallon marine fish only tank. Does this provide any advantages over the use of tap water which is relatively hard? <it really is a disadvantage if you are not aerating it and then re-mineralizing it before use with Seabuffer of some kind. Distilled is too pure and a burden on the alkalinity of marine aquaria. However, once re-mineralized (with the good stuff only, so to speak) it is indeed better than many sources of tap water which are seasonally changing and sometimes laced with contaminants> The second part of the question is if R.O water provides any additional benefits. <not really... and I don't care for it as the process is very wasteful of water. De-Ionizers are much better IMO> My tank is about 5 months old and I am still getting brown algae on the decorative corals.  <yes.. definitely a sign of nutrient export deficiencies> I thought that by using distilled water I would cut down on this.  <only if the nutrients were coming from your tap water. It is more likely that your skimmer doesn't produce enough skimmate daily or that you overfeed/overstock at least a little> Is this accurate and what aside from bleaching the corals can be done to eliminate the algae? <simple nutrient control.. protein skimming alone can cure it. Also carbon, water changes and more careful feeding techniques (do look into feeding and algae topics in the archives of this site)> My tank is 28" deep and I have been using 50/50 and 10,000k fluorescent bulb to light it for approximately 5 hours per day.  <really not enough light. And light alone does not cause algae... nutrients under light cause algae> I like the look of power compacts, is this the way to go (and if so what wattages for a 48"x18'x28') and which bulbs. Will heat be an issue. <If you don't have or will have corals... the lighting is largely an aesthetic preference. Heat is not an issue with any of the well made light canopies... or at least it is quite minor> Thanks again and keep up the great work. <with kind thanks, Anthony>

Water Purification Thanks for your suggestions regarding sea urchins; so far, they're doing well. We've found that using a Tap Water Purifier greatly increases survival of all aquatic life here - I guess that our water is less than perfect. Since we use so much water, I've been thinking of getting a more substantial system - reverse osmosis/deionization or KATI/ANI towers. Do you have a suggestion as to which is the best, for basic improvement in water quality? I need water for both freshwater and saltwater aquaria. <Reverse Osmosis units are my general recommendation for most people. They are easy to use and easy for keep working properly. On the other hand, I have and use a Kati/Ani system and love it. It was about the same initial price as a comparable RO, but the on going costs are considerably less. The major downside is recharging the unit. To do this you have to handle some fairly nasty chemicals, sulphuric acid and sodium hydroxide. These are both dangerous. The other major downside to all deionization units, including the Tap Water Purifier, is if you continue to use them after the resins are exhausted, they will continue to exchange ions. Everything that was absorbed since the last new cartridge or recharge can now become imparted into the newly processed water. You have to determine, can you closely monitor the resins change color and are you safely capable of recharging the units.> Thanks very much. -Ann <You are welcome. -Steven Pro

R.O. v. R.O./DI? (Antoine's opinion... others may vary) Hi Bob, <crew member and author Anthony Calfo in your service> Please comment on the advantages/disadvantages of an R.O. v. R.O./DI system for my 125 gallon FOWLR...  <Both produce very high quality water... but I wouldn't take or use an R/O unit for free. Hobbyist grade units under the best circumstances (new membrane, new prefilters, tempered source water) still only yield at a 4:1 ratio. High grade units (like car wash models) are still only 1:1. That means if you spend $1000.00 or more on a unit that produces at 1:1 (under ideal circumstances only) you will still waste 1 gallon of water down the drain for every good gallon you collect. And in the case of the hobbyist models...there will be 4 to 8 gallons down the drain per. I quite frankly don't have the shame to send likely 500+ gallons of water down the drain just to fill a one hundred gallon tank. And then the water changes, evap water, etc... please! It kills me. The reject water is going to be over 20% more concentrated with all of the undesirables than the raw tap water that you didn't want to use in the first place. So unless you plan on starting your own salt lake or have stock in the water company. Go DI! No membranes to replace (little or no memory to DI resin even in the long run), combined recharge chemicals neutralize and can be drained (caustic but easily degradable, and again... easily neutralized together). And an average recharge costs $2-3 dollars per several thousand gallons of purified water (depending on how close to "average" hardness your source water is... still cheap any way that you look at it!). And there is no waste water. As far as brands... hmmm, I have experience extensively with one brand only (and liked them well enough to spend several thousand dollars on multiple units but still have qualms with them). Let me defer you to the message boards to talk to a wider scope of users for you to make an intelligent consensus from. My strong suggestions are to buy/add a one micron prefilter to the likely 5 micron standard. And add a PolyFilter unit after the carbon chamber. So... at least have 5 micron floss, then 1 micron floss, then carbon, then PolyFilter, and then your two column DI. Add special filters as necessary (phosphate, silicate, etc).> and please recommend a trustworthy manufacturer for each system... Thanks, Knef <best regards, Anthony>

RO units Hello, <cheers, Anthony Calfo in your service> I am pondering the acquisition of an RO unit.  <a dreadful choice compared to a deionizer for the sheer volume of water they waste. Even pressurized $1000 units still have a ratio no better than 1:1 which means that you will put 100 gallons of water down the drain for every 100 gallons that you use. Truly shameful in my opinion. Do read through the archives here on WWM (FAQs, Google search please)... there is ton of information on this subject with various perspectives there> The thing is my marine tank is only 29 gallons, I also have a few freshwater tanks, a two 55s an 80, and a 125 turtle tank. I use tap water treated with prime for the freshies, I'm sure RO water would help with algae problems in those tanks.  <that is not necessarily true... may even be completely wrong. Unless you have tested your tap water and know it to be the source of your nutrient accumulation problem (the cause of the algae)... high phosphates for example. Else, you simply have a nutrient export problem (overfeeding, overstocking, lack of protein skimming, carbon not changes often enough, water changes too small or infrequent, etc)> From what I have been reading on your RO FAQs, I would need to store the freshly made RO, heat, aerate, buffer, and some other stuff.  <yes... for some freshwater and most all marine application> Right now I purchase sea water from the LFS that has been purified for aquarium use, and top off with distilled water (should I aerate the distilled water before topping off?).  <yes... all demineralized water should be aerated then buffered else you waste buffers in the tank or salt mix> It seems that my current method would work better for me considering the small scale that I am working with.  <perhaps> I suppose if I got an RO unit I could separate the output into two containers, one for fresh water and one for marine, and then treat them accordingly from there. Any thoughts? <hmmm... using the waste effluent of the RO for freshwater tanks? Not likely you could even use it all as expensive hobby grade models are 4 to 7 gallons wasted per 1 good gallon produced... most are worse especially if your tap water is hard/bad. Overall... it is a dreadfully wasteful process... do look into rechargeable two column DI units. They don't waste a drop a nd can be tempered buffered with a little hard tap water back into the collected mix for a cheap reconstitution without wasting any water> On a side note, your FAQs are great. Wet Web Media is rapidly becoming my only source for aquarium information. Best Regards, Gage <thanks kindly for saying so... best regards, Anthony>

R.O. Unit Hi Guys, I hope you are doing well. I had a question regarding reverse osmosis units. Okay - I currently have a Oceanic 72 gallon bow front and am planning to upgrade to a 175 gallon bow front. I was just checking out a killer RO unit from Seachem called the PINNACLE "PLUS" SERIES REVERSE OSMOSIS UNIT - 100 GPD. This one is around $800 Canadian which is probably about 55 dollars U.S. (jokes:-) However - I don't know if you can give product endorsements but I would like to know what you all thought before I went and made a major investment like that. <I have not heard anything good or bad about the units. I do like other Seachem products and will tell you they probably do not make these in house. More than likely, someone else makes this and they slap a Seachem label on it. Very common in this industry.> Thanks a lot Guys - peace PS - do you know of any cheaper ones that are high quality? <I like and sell SpectraPure. I do not know if they are any cheaper, though. -Steven Pro>

Re: R.O. UNIT Question Thanks for the advice! I am sure that you have saved me a couple hundred dollars at least- I do appreciate your candor as well, I found it very interesting to know that companies are outsourcing their manufacturing needs which was something that I suspected anyways. <Yes, very common on big, specialized items like RO units, fluorescent lamps, etc. The equipment and processes to make such items is expensive and particular.> I love how they sell you a product like baking soda in a 35 dollar bottle called "Super pH Upper" yeah right. I checked the label and it's straight sodium bicarbonate - I think that more hobbyists need to know about stuff like this... <I always like to see what is in the bottle. I tend to stay away from any product that does not have a list of ingredients.> PS - "Super PH Upper is a purely fictional product and any similarity to any other product is purely coincidental and meant to illustrate the purpose of this joke - thank you. <Nice disclaimer. -Steven Pro>

RO/DI Units In continuing my revamping my salt water attempt, I am looking at buying a RO/DI unit instead of my "buy a new cartridge every 50 gallon" tap water purifier. <A wise choice. An RO unit is more cost-effective if you have anything over a 30 gallon aquarium.> What I need to know is this, is there any difference (other than price) in the units I find in the aquarium magazines and the ones I can buy at most retail outlets? <There maybe slight differences in the after filtration aspect. Many of these, post RO, filter again to change the taste of the water. This may or may not affect your aquarium.> They both claim to do the same thing and are both 5 stage units, but the retail outlet units are several dollars cheaper. <Three things, one you may not even need a 5-stage unit. For most people, purifying tap water merely takes a simple RO unit. Two, take a look at SpectraPure. We have a link for them from www.WetWebMedia.com. This is the brand that I sell to my customers. They are high quality and relatively inexpensive. And three, you may want to consider a DI only unit. The most popular one is from Germany, called a Kati-Ani. Please archive WWM for the discussion on both.> Thanks, Robert <You are welcome. -Steven Pro>

Kati/Ani units Hi everybody- Would you happen to know the difference between the 3 size Kati/Ani units? <They are the same, just larger.> There is a 2, 5, and 10. <There is also a 1, just no longer available from Petwarehouse/Drs. Foster & Smith.> Is it just that the resins will last longer in the bigger ones? <Yes, longer between recharges.> If so, do you know an average on how long each size would last? <Depends exclusively on your water, but for reference I have a 2 size model and get easily over 200 gallons between recharges.> Or just a comparison between the three with the same quality water. <If theoretically the 1 would yield 100 gallons of pure water, the 2 would be good for 200, the 5 for 500 and so on.> I have a 125 FOWLR tank. Is there a size that you would recommend? <The bigger the better.> There is quite a price difference between the sizes. <The 5 should be 2.5 times the 2 and so forth.> Thank you in advance. Dennis <You are welcome. -Steven Pro>

RO/DI Recommendation Bob: <Steven Pro in this morning.> Reading your web site every night. I currently have an 80 gallon salt fish tank for 15 years. Now putting together 125 reef tank. What RO/DI brand and model do you recommend? <I prefer SpectraPure units. Usually I recommend just straight RO units, not a RO/DI. I do not like the wastefulness of mixed bed DI units.> I read you recommended SpectraPure CSP-35 or CSP-60. <These are two different versions of the same product line. You need to determine your water needs to identify the gpd rating, 33 or 60 gpd.> I called the company today and they recommended SP2000-60 for $417 with drinking water kit for $170. <This unit make lab grade water. A bit overkill for aquarium applications.> Seems expensive compared to others I have seen on the web. <The high-end unit plus the drinking water kit is what is making it so expensive in comparison. A plain CSP-60 will work just fine. You can decide if you want the drinking water kit or not.> Thanks, Steve <You are welcome. -Steven Pro>

Re: Funky stuff in water for change Thanks for the quick reply. With regards to the water hardness, and R/O, I have a question. I've read everything I could find about R/O and water softeners. It seem like most people won't make a stand on the softener portion.  <I'm not most people <G>, I have an opinion about most everything...heehee. Softeners (ion exchange) are inappropriate for most aquariums unless the water change schedule is heavy. They all exchange one thing for another and the residual chlorides from sodium or potassium salts accumulate in the aquarium and skew the water chemistry (can wreak havoc with the ALK dynamic). I generally do not recommend them. They are useful for Discus and other fishes that prefer soft water and several times weekly water changes> I do have a water softener and R/0 unit. How do you feel about softeners? Mine uses potassium instead of salt. Is one system better than the other? Is either one dangerous?  <potentially both as per above> The potassium model was much more money. I notice that when I water my yard with it, it dried it out (burned it) so I bypass it for watering. <I would recommend the RO unit instead and reconstitute it sufficiently to make it stable for your fishes> After the wife, kids, and dog are done I'm luck to get a few cups of R/O water a day. What are your thoughts on water after the softener, before the R/O? <wouldn't use it> Also, don't R/O remove all trace elements too? <for saltwater use, RO is fine to have a consistent pure base to start with, then aerate, buffer and salt. Please read through our archives with a keyword search on Ro or DI water. The topic has been covered in the FAQs extensively> Thanks again for your time, Mike <best regards, Anthony>

RO System Bryan again, I have a question on RO units. IYO, what is/are the best RO units out there. <I like SpectraPure.> Looking at buying a new, and everyone claims to be the best. Also anything to look for or look out for? <I generally do not sell or deem necessary the mixed bed DI cartridges found in the RO/DI units. A regular RO unit maintained well with decent tapwater will serve most people well.> Thanks, Bryan <You are welcome. -Steven Pro>

Filtration I am going to be purchasing 2 things for my reef, a Reverse Osmosis filter and a better protein skimmer. I have a very bad case of algae in my reef now but the animals don't seen to be harmed which should I purchase first? My old skimmer is a Cheap Sea clone.  <<If it were me... the R.O. device... best/better to start out with good water from the start. Bob Fenner>>

Skimmer or RO/DI ? If you had a 55 gallon FO tank with a sump would you buy a protein skimmer or a  DI\RO unit. I have a few pieces of dead coral with: 2 Damsels 2 Clown fish 1 Fox face 1 Naso tang 1 Yellow tank 1 Imperator Angel all levels are great but I get that brown algae growing every two or three weeks  because I use tap water for both top off water and water changes. I do a 10%  water change every two weeks and vacuum the gravel but the diatoms, of course,  still come back. Now, I have heard that a good protein skimmer or a DI/RO unit will  help with this. I was thinking of getting the Kent Marine Maxima RO/Deionization Unit or the Berlin Venturi Skimmer. So which one would you buy?  <<No doubt about it... the skimmer. If your water is too bunk for aquarium use... you ought to not drink or cook with it... Look into an R.O. device going forward for all these purposes. Bob Fenner>>

Water purifier Hi Bob! I'm looking into purchasing a water purifier (RO/DI) unit but I'm not sure what to look for. My goal is to use this unit with a storage tank for drinking water and a connection so I can fill a 5gal bucket for water changes. The tank is a 50 gal reef so I'm concerned with silicates, etc. Any ideas on a brand name and/or system components to look for? Thank you for your help!! Michael Ruff <<For me, I'd just buy an inexpensive consumer unit (this is what I use), and utilize the usual in-line carbon/D.E. filters ahead of it... These can be purchased over the Net as well as the big department stores. Fittings, tubing and valves for diverting the produced cleaner water, diverting the "waste water" (as in to your pond, lawn...) can be purchased there as well. Bob Fenner>>

RO/DI Bob, I just read through the FAQ's and you mentioned using a unit from Home Depot. REALLY!? I'm looking for a unit (CHEAP!) myself and was wondering if you tested the water after it runs through? What were your results? Is maintenance/membrane replacement the same as "hobby" models? Could you recommend at specific model you have first-hand experience with? Thanks, Tony <Yes, these units are 99 percent plus as useful as the ones "remarketed" for aquarium use (they are, no surprise, made by the same manufacturers)... maintenance of these units is identical... and any/all models will do, I assure you... Don't recall the brands, models I've purchased, but do use "just" the home use type myself. Bob Fenner>

RO Dear Mr. Fenner: Any recommendations on a small-capacity RO unit for a reef tank? <Definitely. Just one of the inexpensive units from a large "home improvement" warehouse or internet/mail-order equivalent. This is what I/we use for drinking, cooking, pet-fish use and it/they are fine. Easy to install, use... and handy (no lugging, driving)... and low cost (less than a penny a gallon)...  Bob Fenner>

Tap water purifier I have been feeling guilty about setting up a new reef tank when there is so much to be done with the old one. It is only a ten gallon so its kind of hard to get excited about it but I feel a responsibility to the animals I keep.  <This adds up?> I have been battling blue green algae for the entire life of the tank(4 months or so). I am blaming the algae on some or all of these factors: 1. I use city water which I just let sit around a couple of days to get rid of chlorine <It's chloramine... takes about a week to dissipate> 2.My lights come on at 10 in the morning to ten at night which gives them about 3 hours of natural sunlight 3. I have no skimmer-would like to a get a Prizm but all money must go for the cause (55 gallon reef) <Then close down the ten> 4.Occasionally my mother thinks the fish look hungry and feeds them more then usual (am working on this). Who dun it? <You... apathy, lack of planning/execution/commitment, poor maintenance, too small a system, instability... Don't place blame on your mother... you could hide the foods, explain why she should not feed... Empathy, but no sympathy from me> I found a very great site on reefs called reef sources (reefsources.itgo.com) <this URL doesn't open...> which clearly tells your how to set up a reef. The guy who made the site recommends a "tapwater purifier by aquarium pharmaceuticals". Its cheaper then RO and I would like to use it for my ten gallon and my 55 gallon. What do you think? Will it work for my reef or just for the ten gallon. <Cheaper up front for okay water conditioning... much more money per gallon in the long term... Okay for a ten gallon, perhaps a ten and fifty five... do the math... do you need cleaner water from your starting source for pet-fish? For household use? Reverse osmosis is cheaper, better for hundreds of gallons a month use> Finally can I use my Tidepool wet dry on my reef or would you defiantly use macroalgae and rock? I am really enjoying this hobby and am even thinking about learning to scuba dive. <I'd use both. Definitely take up diving... you will greatly benefit from the added awareness, discipline, exercise.> Thanks in advance, Andrew <Be chatting my impetuous friend. Bob Fenner, www.wetwebmedia.com> PS I just bought the Marine Atlas and I noticed that a lot of European tanks have TONS of macroalgae in them. is this how European reefers get away with wet dry filters?

Re: tap water purifier The correct url for reef sources is: reefsources.itgo.com/features/index.html Can I use less live rock if I use the wet dry filter? <Very nice site, content and format wise... will add to the WWM links pages today. Thank you for this. And yes, same live rock... even small bits, mucky mud at the bottom of the box it is/was shipped in. Bob Fenner>

Re: tap water purifier Could you clarify your answer?  <I'll certainly try> I was thinking that maybe since the rock and wet dry filter do sort of the same process  <Not really... read over the marine filtration areas of the site: www.WetWebMedia.com.... the W/D likely acts as a mechanical filter, nitrification source... aerator... out gasser... the LR as a denitrifying source...> maybe I could use a little less live rock to save a little money. I could buy more for looks at the LFS. <For larger volume deals, like 40-45 pounds, look for whole box deals from e-tailers... A few of them are listed on the WWM links pages> I only need water treatment for my pet fish(65 gallons total) so would you recommend a RO or a Tap water purifier? Could you recommend a good RO? <See the water treatment articles and FAQs pages on the WWM site> It is going to be a tight squeeze to fit all the wet dry and the macro algae sump in the stand, leaving no room for things like a calcium reactor. Thanks in advance, Andrew <Many things to consider, engineer. Bob Fenner>

Re: Reverse Osmosis flush water Thank you for your quick response and comprehendible answer. Do you know anything about Coralife ROs?  <A little... they're made by other people... just re-labeled> I think I would rather have a complete RO instead of a barebones unit. Will my reef be fine with a cellulose triacetate membrane for the RO?  <Yes, this is what the vast majority of R.O. units utilize... there is a plant that makes them in northern San Diego, where we live.> I am looking into a Coralife CTA 24 gallon a day unit. The main factor I'm concerned about is waste water. I would not like to spend $140 for something that produces 10 gallons of waste water for every one gallon of pure water.  <This flush water ration seems a bit high... should be more like 4 gallons per 1 made... and BTW, you don't need to "throw away" that flush water... we vent ours to the swimming pool or Koi pond on different properties...> On the fish, you don't think that 7 fish is too much?  <Umm, seven fish? Too much? Sorry... read through a couple of hundred messages a day, besides sleeping, cooking and cleaning... don't recall size, shape, livestock plan...> I do plan on establishing macroalgae and purchasing a UV sterilizer before I add the powder blue tang along with reading more about this beautiful species. Sorry for the boring questions about water, Andrew <Keep studying my friend. When you are ready, you will know. Bob Fenner>

Water Purification (gear choices) Hi again and thanks for the help with my previous questions. I ended up fitting my 40G with a CF lighting unit -- one blue, one 10,000K. The question of the day is about water purification! :-) As mentioned, I am in the process of setting up a reef/coral/invert + fish tank. I'm breaking in the tank right now and have everything running with the equipment on + substrate + live rock. I'm almost one week in and will wait/suffer/die-of-boredom about another two before intentionally putting anything live into the tank. <You won't die of boredom... observe what is going on in your system> What worries me is that corals and inverts tend to like/need really good water quality. Currently I'm just using tap from the sink (city water). I'm looking into some RO and RO/DI units and am not really sure what to get. As far as the RO units go, 2, 3, 4, and 5 stage units seem to be the most common and are not too far apart in price. As far as the stages are concerned, what would you recommend? <To investigate further the "quality" of your tapwater... if it's fine for you to drink, use for cooking, it is likely fine for pet-fish use> Also would you recommend a RO unit with DI capabilities, or to just stick with a plain RO unit? <The plain... is what I/we use or just tap> I've also noticed that the plain RO units for home and the aquarium seem unsettlingly similar, are they in fact the same or close enough? <They are for the most part identical... the trade re-labels these...> Here are the specs for a system that I am currently looking at. Please take a look at them and let me know if they are adequate, under kill, overkill, or recommended... Manufacturer: Unknown Stages: 5 Capacity: 50 GPD Rejection: Up to 99% Stage 1: 50 m sediment prefilter Stage 2: 1 m sediment prefilter Stage 3: 10 m active carbon Stage 4: TFT (up to 99% rejection) Stage 5: De-Ionizer Thanks again for your time and help in my quest to not kill the little fishies and to be a responsible aquarist! Stan <This unit is way "overkill" but certainly will work... a prefilter, carbon and tris membrane is really all you need/want... no de-ionizer necessary. Bob Fenner... who often wonders, do folks consider all the chemicals added from livestock, dissolving rock, substrate, foods, the air...>

Purifying Water Dear Bob, My wife and I thoroughly enjoy your website and appreciated your help on our question regarding cycling live rock. We now turn our attention to water purifying and would appreciate your input. <A pleasure my friend> We have been using the Tap Water Purifier (TWP) from Aquarium Pharmaceuticals since we began this hobby a few months ago. We get only about 15 to 20 gallons from the units and so are paying a premium for this water. We also noticed that nitrite is present in the resulting water. <Yes... you should investigate a reverse osmosis unit for your pet-fish use as well as drinking and cooking> We read your articles on water purifying and were elated to hear of a more economical method of purifying water. After reading the articles and the FAQs, I would like to make sure I understood your process correctly. So here's what I think is your process for purifying tap water. Please correct any misunderstandings: 1. Prepare, ahead of time, a solution of 1 pound Sodium thiosulfate in 1/2 gallon water. (I'm using half of your recipe). 2. Pour 15 gallons of tap water into a Rubbermaid rectangular container. 3. Treat the 15 gallons of water with 30 drops of the Sodium thiosulfate solution and let sit for an hour. (We have very bad tap water). <Bad?> 4. Load an Eheim canister filter with high-quality activated carbon and pump the treated 15 gallons through the canister and into the Rubbermaid Brute trash can. 5. In the Brute container, mix the salt. 6. Place a power head and heater in the Brute container, turn them on, close the lid, and let them run for a week or more. Any corrections/improvements? <Depending on what you mean by "bad"... I would look into RO...> How often should we replace the carbon in the canister filter? <Depends once again on what you are trying to remove by its use... easy enough to get/use test kits for whatever these materials are... and switch out the carbon when exhausted... by testing for same> As we said, it was great to learn of a more economical means of purifying tap water. We highly value your articles and FAQs, and constantly read the website. <Thank you again. Higher praise, result I do not hope for. Bob Fenner> Best regards, Michael and Lynn Rivera

Purifying Water Bob, My wife and I are always amazed at your quick response and great advice. <I key quickly> As for your suggestion regarding a RO unit, our water in this area is very, very expensive. I understand that the RO unit wastes about 10 gallons for each 1 gallon of pure water. The wasted water is not good for drinking, cooking, or any other human consumption. Is this correct? <Good question... there are some units that are this profligate, but many produce a gallon of water by venting three or four to "waste"... and this water is fine for... irrigation, a fish pond... perhaps both... And this is not your only option. There is a fabulous "Kold-Steril" filter made by Poly-Bio-Marine (link on the www.WetWebMedia.com links page), that wastes no water at all... Do check your water bill... source water is very inexpensive (about $1.80 here in Southern California per hcf/hundred cubic feet, about 748 gallons, less than 2 and a half cents a gallon... compared with driving, buying and hauling bottled water? R.O. is a bargain.> If I cannot use a RO, any suggestions on what I should be testing for after running the Sodium thiosulfate treated water through the canister filter? <Whatever concerns you... Please try to understand my hesitation here... I don't know what's "in your water" that is problematical... If it's "excess" sanitizer, you may want to get/use a chloramine test kit for instance...> Again, we highly value your opinion and really want to get this right before moving on. Best regards, Michael and Lynn Rivera <Do keep investigating, chatting with your water district, fellow consumers... till you think/feel you know enough to decide... the vast majority of cases/circumstances are best dealt with by RO technology. Bob Fenner>

Re: Water Filtration You recommend the "fabulous "Kold-Steril" filter made by Poly-Bio-Marine" over standard RO filters? I need to order one this week and would like your suggestion. This filter will be used to mix salt water and for cooking/drinking. <Yes... given no further information on your source water content, cost. Bob Fenner> Thanks

R/O systems for saltwater Hi Mr. Fenner, I have one question today. I've started looking at manufacturers websites, and comparing R/O systems.  <Good practice> I've also looked at m.o.p.s.com (the Canadian wholesaler since I live in Montreal). I want to compare these with the types you can buy at Home depot type stores, because I've read the FAQs on your site, and you say they are o.k. to use (basically the same, only marketed, and packaged different for the aquarium industry). <To a very large extent, yes. In point of fact I use a HD sourced unit myself> What exactly should it specify on the package that it can filter? My knowledgeable reef-wise friend says the Home Depot styles are not good enough because there is one thing they don't do as compared to the ones specifically designed for aquarium use. He did not specify what, but I just wanted to hear your take on this. <Bizarre... Well there are two things wrong with this person's declared opinions... but I won't tell you or him what they are...> What brands do you find good if I go with the type for aquariums? <Again, look for ease of maintenance, capacity, cost of replacement membranes and carbon-cartridges... Ask other people in your "source water" district what they do, and why here. You very likely don't need added deionization, other particulate pre-filtering... maybe a change/addition in "storage technology" if you're needing/using lots (tens of gallons at a time plus) reverse osmosis water. Bob Fenner> Thanks in advance, Greg N., Montreal, Canada.

Water purification I have a 75 gallon reef aquarium. I'm currently using the Aquarium Pharmaceuticals tap water purifier. It is advertised as being able to make 50 - 150 gallons of water depending on water quality. My water quality must be really bad because I can only purify 10 - 12 gallons before having to buy a new filter.  <Yikes, what? Have you contacted the fine folks at AP? I will cc your message to their technical staff> At around $15 per filter this is getting rather expensive. I have a water distiller which I use for my drinking and cooking water.  <A distiller? Really? I would use a reverse osmosis device for alls purposes here...> I have been told by numerous people that you can't use distilled water because it's too pure and doesn't have enough oxygen in it.  <Hmm, well, on exposure to the air, gasses will/do enter distilled water... but it's not economical to use for aquarium purposes...> (I'm just repeating what I've been told.) Could I mix the distilled water with the DI water? <Yes... or just use deionized water... or...> Could I add minerals back to the distilled water?  <Yes> Could I aerate it to put oxygen back into it?  <Yes> Are people just telling me nonsense and I really can use the distilled water for top off and water changes? <For topping off distilled is ideal... not necessary for water changes... but can be used, definitely> I do not want to buy a RO unit, since I already have a distiller. I've been thinking about pre-filtering the water before I run it through the DI unit. This should make the resin last longer.  <Yes... am curious as to what you mean by the TWP resins are not "lasting"... by what measure? Think there may be something operatively that you're not doing here. Bob Fenner, WetWebMedia.com> Charcoal filters aren't as expensive as the DI filters are. Thanks in advance for your help in this matter. Michelle

H2O filters for home/reef Good evening Mr. Fenner. I've been doing some soul searching and have come to the conclusion that the only way to truly end my dreaded battle with diatoms is to purchase some form of water purification system for my home. <A good "first line" of prevention> I'd like to tap into your knowledge for a little help with this decision. I've been looking into RO/DI systems for under counter use, as well as H2O softener systems for the whole house. Is it preferential to use one system over the other, or is the best benefit found when using both?  <The RO and or RO/DI is fine for all in my opinion... Most water softening systems incorporate similar to deionizing resin technology/strategies... redundant> Also, I have seen a huge variance in types of RO/DI systems around. They range from 3-4-5-6 stages, and 25 to 125 GPD output. I've seen the best prices, but also the most variance on a popular auction site. Is there anything to be looking out for as a quality alarm, or are the systems pretty solid, with just preferences being a factor (regarding stages)? <Mainly the latter. A good all-purpose household unit is fine... really.> I want the best for my reef animals, but this is also an investment for the home and family. Take care and God Bless. Jason Harris <I understand... we use a "cheapy" warehouse store unit... and change the carbon pre-filters often (every couple of thousand gallons)... the RO membranes about every ten pre-filter changes... Bob Fenner>

Domestic Water Softeners Is it ok to use water in my cichlid aquarium that comes from a domestic water softener. <Mmm... depends... on what sorts/species of cichlids you're talking about... some like Symphysodon (Discus), many South American Dwarf Cichlids... enjoy very soft water and have a moderate tolerance for the free sodium that such water conditioning devices produce... The bulk of the family Cichlidae require or do better with minerals, salts "added back" by the use of home-made or store-bought "replacement" supplements. So... Need to know what's already in your water (you can find out by asking your supplier or having it tested, testing yourself...), what types of livestock you intend on keeping, and what, if anything you are going to do to modify the softened water before using. Bob Fenner>

Re: Domestic Water Softeners Thanks for your response. I keep African Rift Lake cichlids in a 75 gallon tank. I do not add any supplements to the water I just use it straight from the tap. I have a ph of 8.5, GH of 11 and KH of 9 (German degrees). <Ahh, this should be fine for most all Lake Tanganyika and Malawi species... though some folks do supplement this quality water as well> I have been using non softened water from a tap directly on the mains supply bypassing the softener. The problem is having to heat up enough water to get the right temperature. I was thinking of using the softened water that comes out of the hot tap to save time. I have worked out that approx 1/4 of the water would be from the hot tap. <Mmm I understand... I would develop/use another strategy... the best, and one commonly utilized by many breeders, is to store, heat the water a few days ahead of use... with resistant heaters, or with very large volumes, through contactors with the heated water recirculated through a gas water heater> I believe that the salt used in home water softeners is only used to clean the resins that are in the softeners tank and get flushed out to the drain during the recharge operation. Is this the case? <Mmm, not typically... they're "ion-exchange" types by and large, with (depending on type of water, resins) more sodium being flushed in excess quantity with the "softened" product.> If so then does that mean that the softened water does not contain extra sodium. <Yes. Please read: http://www.ianr.unl.edu/pubs/housing/g946.htm> Thanks for your help. David <Not all technologies are the same... but this is the most common case. Bob Fenner>

Re: Domestic Water Softeners Thanks again for your reply. I think I will have to continue to boil the hard water to correct the temperature. I will enquire with the manufacturer of my home water softener (Waterside) and ask how it works. You might be interested in the link below which is where I got my original information from. http://www.btinternet.com/~aquariumcity/filters/How_Softerners_Work.htm <Thank you for this... will post to Daily FAQs then on to the Water Quality sections of our sites. Bob Fenner> Thanks again, David

Water purification and confusion Hello Bob. <Hello> I have been reading up on the Kold Ster-il purifier by Poly-Bio Marine. This seems to me to be a better way to go if one wants to purify their water. They claim up to 5000 gallons before media replacement is needed and it doesn't strip the water of minerals. It also has the benefit of being many more times faster than a RO/DI unit? They also claim it makes great drinking water. What say you? It sounds good to me? <This is a very good product> Confusion? In November and December issues of FAMA, the WaterMarc articles leave me with questions about skimming and Ich outbreaks. <These are badly written advert.s. Ignore them> If you have not read the articles I would like to ask if you would please do so. The two gentleman being interviewed say some pretty wild and to me at least, previously unheard of theories about skimming and Ich. I figured I would just ask Mr. Fishman himself and see what he says. <The company is a discredit to the industry. Bob Fenner> Zimmy

Re: New 55g tank, ro/di water confusion!!! ... Robert, thank you for your quick reply!! I am now considering RO unit only rather than RO/DI after reading your info here, that would save on media. My tap water GH/kH is very low, pretty soft water, really, but I do have some problems with diatoms in my freshwater tanks so I do not want to chance it with the salt tank. You say to not use Kalkwasser, it seems most people are using this. What two-part supplement will be okay for me (B-Ionic??) <A fine and much better choice than calcium hydroxide> and will be reasonably priced?  <Shop about... on the Net> I am very interested in anemones, I have Eric Borneman's book Aquarium Corals and am finding it very helpful in understanding corals, can you recommend a book on anemones? <Mmm, volume 2 of The Modern Coral Reef Aquarium by Sven Fossa and Alf Nilsen, Allen and Fautin's Anemonefish book, ditto for Joyce Wilkerson's... and a cursory reading of the anecdotal accounts archived on the Breeder's Registry on the Net> I wasn't a big fan of Daphne's' book Clownfishes and their host anemones, maybe you can recommend an alternative. <Oh!> Thank you for your time, your help is greatly appreciated. Also, can you tell me if a long-nosed butterfly fish would be an impractical choice for a 55g reef tank? After reading your reef stocking section I am thinking maybe so. Thanks, Angela. <A good choice though this is a bare minimum size system for Forcipigers. Bob Fenner>

Questions: Silicate removal, tapwater treatment  Hi Anthony, <Good morning, my friend> Thanks for the fast response. This is a follow up of the questions that I asked earlier: I keep feather and grape Caulerpa. Will they absorb silicates? <not at all to the extent that I suspect you, like most folks, will desire. More so, they will exude far many more noxious compounds that at best inhibit water clarity as bad or worse than any other biological byproduct of aquariology...and at worst literally inhibit the growth of some corals (not all, of course...some species are better adapted and seemingly unfazed)> Regarding the control inflow source water with chemical media if necessary... What do you think of the tap water purifier by Aquarium Pharmaceutical Inc? <I think it is the long way around the barn, so to speak. For what you are likely to spend on replacement cartridges in less than two years, you can easily afford a rechargeable two column de-ionizer that is a more responsible choice that also saves you money (like the KATI/ANI brand units). Quite frankly, I resent the mixed bed resin products that deliberately make it inconvenient for an aquarist to reuse an entirely rechargeable and renewable resource (the resin if it were separated as Cation and Anion instead of mixed in cartridges as they often are). It seems like an ironic waste in an industry that is founded on empathy and admiration for the natural environment. Anthony Calfo>

Water to buy in containers of 1 gallon at a local store nationwide Is this unit better than the MPDI-35? <Yes> How long to make-up gallons of water? <All RO unit are labeled by how many gallons they will make in a day. CSP-35 is 35 gallons in 24 hours under the best case scenario.> Does it hook up to a hose or something? <It will come with hose fitting.> How long does it last? Thanks! <The prefilters generally last about one year. The membrane will last 2-5 years depending on your water, if you change the prefilters on time, etc.  -Steven Pro>

Re: water to buy in containers of 1 gallon at a local store nationwide Let me try again as my wife will not let me do an RO unit in our home: <Why is this? Buying your own RO will save you money over buying someone else's RO water. RO unit can be connected and disconnected to any faucet with an adapter and the unit themselves are not that big. The biggest drawback is whatever you hold the water in temporarily.> [1] Please tell me the name of a nationwide company that sells by the gallon container RO water, DI water, Spring water or Distilled water acceptable for my 125 g tank? Thanks for your help please, bcr 2/8/2002 <Do not know of any nationwide company like that. Try a local bottle water supplier, like Culligan. Spring and distilled and no good. Only RO or DI.> [2] I have a 12 year old 125 gallon reef tank, with a 30 g sump. My livestock includes: 11 Fish: red sea purple tang, Foxface, pair of maroon clown white stripe, long nose hawkfish, 2 marine catfish, lawnmower blenny, 3 domino damsels. Inverts: allot of mushrooms [red, green, metallic green, blue], colt coral, flower pot, 2 anemones, 2 brains, a clam, a bunch of polyps, leather coral, a bunch of shrimp, several cucumbers, Gorgonian, red chili coral; Equipment: 30 gallon sump with EV150 protein skimmer with a 2500 Rio powerhead, and a return ViaAqua 4900 powerhead. Lights: 3 VHO Coralife 60 inch bulbs with 140 watts each, 2 are 10,000 K, the other actinic; 2 65 watt actinic power packs for a total 550 watts or 4 watts per gallon. Circulation in the 125 g tank is from 2 powerheads [a Otto 2000, and a 1700 Rio]. Live rock: 150 LBS Tonga, Fiji, Marshall Island]. Live sand: 2-3 inches total mixed with about 1 inch of Aragamite coral. Additives I use are mostly Kent Marine products Strontium & Moly, Iodine, Phytoplex, Micro-Vert, salt, Lugol's solution, Kalkwasser, and Liquid Calcium. Thanks ! -John <You are welcome. -Steven Pro>

Re: water to buy in containers of 1 gallon at a local store nationwide Which is the best RO Or DI? <DI water is higher quality, but not always needed.> WATER unit AND WHICH company do I buy it from and what size do I need [ e.g. how much water do I need to change and how often for the 125 g tank? thanks <I like SpectraPure, http://www.spectrapure.com/. The CSP-35 or 60 should be good for a 125 gallon tank.>

Spring water: is it ok to use? Spring water: Is it ok to use in 125 g reef tank?  <Perhaps... matters what sort of livestock... your desires, what the make-up of the water is.> RO water or DI water is too hard to do in our home, unless it comes in 1 gallon containers made by some company [if so name please]. Help please, John <Please read here: http://www.wetwebmedia.com/water4maruse.htm and the linked files beyond. Bob Fenner>

Is Spring water ok for my 125 g reef tank? Hello Bob, <You actually have Steven Pro today. I am one of the WWM crew that helps out answering some of the daily questions.> I have 2 questions please for your attention: [1] Spring water: is it ok to use it completely in my 12 year old 125 gallon reef tank, for water changes as well as replacing evaporated water loss? <Spring water is just that. Water that comes from a spring and makes no claims about being pure. Possibly no better for your tank than tapwater.> My livestock includes: 11 Fish: red sea purple tang, Foxface, pair of maroon clown white stripe, long nose hawkfish, 2 marine catfish, lawnmower blenny, 3 domino damsels. Inverts: allot of mushrooms [red, green, metallic green, blue], colt coral, flower pot, 2 anemones, <How long have you had the Goniopora and anemones? Neither are very hardy and I was wondering what you were doing to keep them alive. Most seem to die off after about one year. Truly tragic.> 2 brains, a clam, a bunch of polyps, leather coral, a bunch of shrimp, several cucumbers, gorgonian, red chili coral; Equipment: 30 gallon sump with EV150 protein skimmer with a 2500 Rio powerhead, and a return ViaAqua 4900 powerhead. Lights: 3 VHO Coralife 60 inch bulbs with 140 watts each, 2 are 10,000 K, the other actinic; 2 65 watt actinic power packs for a total of 4 watts per gallon. 125 g tank has circulation from 2 powerheads [a Otto 2000 and a 1700 Rio]. Live rock: 150 LBS [Tonga, Fiji, Marshall island]. Live sand: 2-3 inches total mixed with about 1 inch of Aragamite coral. Additives I use are all Kent Marine products Strontium & Moly, Iodine, Phytoplex, Micro-Vert, salt, Lugol's solution, Kalkwasser, and Liquid Calcium. [2] Please tell me the name of a nationwide company that sells RO water, DI water, or Spring water acceptable for my 125 g tank? <I like Spectrapure brand RO's. You can probably find a local sales company from the Spectrapure webpage, http://www.spectrapure.com/.> Thanks for your help please, bcr <You are welcome. -Steven Pro>

CSP 60 or 35? Will this set up on the bathroom sink area while it does its things of say 15 gallons on the days I do the water change? Is it moveable? Can I store it in the bathroom closet when not being used? <Yes, yes, and yes> CSP 60 only costs a little more than the 35, should that be one I buy? <I would definitely go for the larger unit. I will give you another tip. Buy a garbage can (that you only use for the tank) that comes with four wheel on the bottom. The kind that cleaning people use in office buildings. You can buy these at Home Depots. They are great for holding water and far easier to move around than carrying buckets. A pump with hose would be another useful tool to pump the new water from the bucket up into the tank. -Steven Pro>

Tap water Purifier The Tap water Purifier is that an option here for me if I am only going to do 15 gallons per week? <It will cost you more money over the long term in replacement filters. -Steven Pro>

Re: CSP 60 or 35? Ss the water quality the same or equal with either unit? <Similar. You can begin your education here http://www.wetwebmedia.com/water4maruse.htm -Steven Pro>

RO or RO/DI I have a few questions about RO and RO/DI units. 1. Do I need RO/DI? Will RO be just as good? I want the best for the fish and inverts. <R/O wastes a lot of water.. plain DI would be best. Combo if your water is really bad> 2. I have read that you should not turn off RO units, turning them off will decrease the filters life. If this is true, What about RO/DI units? <no experience and dubious if the units are flushed regularly> 3. I have also been told that RO waste a lot of water, does RO/DI? <yes... an obscene amount> 4. If I purchase a Rubbermaid can with lid, how will I be certain that no ill chemicals will be leaching into the water being stored from RO or RO/DI? <they are commonly used safely but come with no guarantees> 5. How long can I store RO or RO/DI water in a rubber maid with lid? <aerated and dark for weeks> 6. I have seen attachments for drinking water on RO units, is there a way of getting an attachment to work with RO/DI units? <no idea... please check with mfg> 7. Which units would you recommend for a 120-gallon marine tank? I Will eventually be adding inverts and fish. <I like the Kati Ani brand DI units> I have been doing a great deal of reading on your site and others, but I am having no luck finding these answers. Your direction and help would be greatly appreciated. Thank you, Jesse <Best regards, Anthony>

Re: Ecosystem 40m filter and water quality Bob, Close! Mega-ohms. The measurement of resistively (the reciprocal [1/x] of conductivity.) the water would be approx. 0.0561 microSiemens of conductivity after the high vacuum degasification. Independent D.I. testing is done daily, both online and manually. <Ahh! Yes> The water is far better than good enough to make microchips on wafers; I thought it would be good enough to put in the tank. Maybe the degasification process could deprive the coral of adequate o2 and shock the brain coral. <Yes... but not if only a portion of water changed out... or if the new is adequately stored, and aerated ahead of use... a very good practice. Please read: http://www.wetwebmedia.com/water4maruse.htm> I'll go get some good R.O. to be sure. <A cheapy home unit would/will be fine.> Thanks for the great help. jS <You're welcome. Bob Fenner>

RO Water I worship your wisdom. I must admit I'm on your site quite a bit and have learned a lot. I thank you. I tend to follow your (and Calfo w/corals) recommendations. I do weekly water changes(5 gals for a 45 tank). I have been adding corals w/ success (so far) and would eventually like to have a maxima/crocea clam, leaning more towards the crocea. I am fearful I may not be able to suit its needs. I have 250MH and 110PC lighting. I add calcium (Kalk) strontium and very little iodine via drip overnight. My testing has been pretty good, Cal around 400, PH 8.2, ALK 12.5, very low if any nitrate, etc., also very stable in PH/ALK readings. Phosphate and Chlorine is my concern. My tap water-straight form the faucet-has .17 phosphate level. I seem to obtain a .3 to .6 in the tank. I'm waiting on a chorine test so that is questionable.  I use Chemi pure, Polyfilter (it's a tan /yellow brown color when in need of change), and an Aqua C Remora skimmer. We pay for our H2O and RO wastes so much. Barry at ClamsDirect stated he highly rec.s RO/DI for clams. Do you think I could get away with just a 2 stage from home depot? My husband already complains about the time I take between the tank and you (site). I presented the RO issue to him and he does not want to waste the water etc. I read your facts and realize I do need to consider chlorine and possibly other pollutants I can't test for but any suggestions from you would be highly appreciated. Sincerely, Sharon  <Sharon, the company that produces the PolyFilter also has a cold sterilization system with no waste water. You might want to do a search on that. I'm also thinking if you had a 10 gallon tank and ran your makeup water through a hang on power filter with a Polyfilter pad for 24 hours, I would certainly think any pollutants would be removed from the water including phosphate. James (Salty Dog)>

RO/DI Follow-up - Problem Solved? THANK YOU, I did not know the two stage filters waste water too. Yes, the waste water is the problem. I am going with the 10 gal w/ poly filter and I'll get a filter for the faucet like Pur/ Brita. THANKS AGAIN  <You're welcome. James (Salty Dog)> 

RO Water I forgot to mention I have read facts and your recommendations on H2O. I have no silicate and I do mix up the water a week in advance. Also, according to our water co. and given we had a water line break, our chlorine is quite low (I do intend and waiting on my own testing). In fact, they told me it was not a break since the way they test is by a chlorine test. They told me it was a stream until I brought them in my garage to hear the noise. They were surprised and may be due to us living at the bottom of a steep hill. I also read about the Kold Steril but wondering if this is necessary given your fact on the two stage cheaper route. I just don't want to buy the two stage and then have to upgrade. I thank you and sorry for the lengthy request. THANKS AGAIN!  <I thought your husband didn't want you to use RO because of the waste water. Anyway, most two stage units work with chlorinated water only, removing about 90% of most pollutants and 50/70% of existing nitrate. The chlorine prevents mold and bacteria from developing in the membrane. The choice is yours. James (Salty Dog)>



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