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FAQs on Tapwater Filtration: Reverse Osmosis, Deionized, Distilled Water 1

Related FAQs: 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, Selection, 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

The real thing...

RO/DI Bob, I have two questions regarding RO/DI water purification--currently I have a Kent Marine 50 gpd RO unit in series with the Tap Water Purifier (the latter because I keep discus as well as marine aquariums--perhaps a bit of "overkill" to obtain soft water with low pH). First, is it reasonable to assume that an increase in the rate of color change in the TWP resin would be an accurate indicator that the RO membrane (TFC) should be replaced (as a substitute for laborious testing of RO output water chemistry)? <The membrane and/or the prefilters> Second, does the new membrane require any form of pre-treatment (the limited instructions for the replacement membrane suggest high pressure "rinsing" of the membrane to remove some form of preservative (presumably with dechlorinated water to avoid damaging the membrane) followed by pre-running the unit for 2 hours before use of water product)? Sorry for this somewhat contorted question, but I can't remember what steps I went through for the original set-up approximately 4-5 years ago. <Far better to contact Kent Customer service and have them walk you through their procedures. We should have a link to them on our link page. -Steven Pro> Thanks in advance for your input. Dana

RO Water Buffering I've been noticing a lot of e-mails regarding pH buffering of R.O. water. Is this advisable for tanks with higher pH (mine is 8.4-8.5) in the middle of the day. I do not buffer my water at all or circulate the water before I use it (on top off water or water changes). I use Tropic Marin salt that mixes to 8.5. I keep a lot of sensitive corals and clams, so if I need to change something I will. I do circulate the water for my water changes but use no buffers. Thanks, Jeremy <It is always best to aerate your demineralized water prior to any use. This drives of carbon dioxide and promotes maximum dissolved oxygen. Whether you need a buffer or not depends on your salt mix. Some are designed for use with tapwater and others for RO/DI. Best bet, test your newly made water for pH, alkalinity, and calcium levels. If they are optimum, no need for extra buffers. -Steven Pro>

Another RO Question Hello everybody, Yes, I just read on your FAQs that you said you need to buffer and aerate the RO water before putting it in. Do you need to do this with regular water changes on a FOWLR or is this only for a reef tank? <Usually, for all RO water. -Steven Pro>

RO Water Hi Anthony, What do you use to buffer the RO water, and what test is used?  -R. Gibson <Aquarium Systems SeaBuffer and Seachem's Reef Builder and Marine Buffer are all good products. The easiest thing to do is aerate and heat your water first. Then add and mix your salt. At that point, test pH and alkalinity and adjust as needed with any of the above products. -Steven Pro>

RO Water II Steven Pro, Do you buffer the water that you add to your sump due to evaporation. -R. Gibson <No, but I do aerate the water and mix it with Kalkwasser. -Steven Pro>

Water Purification Thanks for the advice regarding water purification. I'm still debating between KATI/ANI and an RO or RO/DI system. For freshwater fish, what treatment does the water need after each? <After all systems the water will need aerated, heated, and then reconstituted (buffered).> Obviously with the RO/DI, I'd need to use some sort of product to reconstitute the water (there seems to be a Kent product for freshwater?). <Many others, too.> What do you need to use with water produced using KATI/ANI or RO alone? <Many people simply use, say half and half, demineralized water to dechlorinated tapwater. It is best to use test kits to verify how much of each is needed to obtain the desired pH, hardness, conductivity, etc.> Thanks very much. -Ann <You are welcome. -Steven Pro>

Leaky plumbing Dear Robert (or Steven), <Anthony Calfo... and now we have a full house... or at least three jokers> Thanks again for all of your previous advice - it has been very helpful. I have now obtained an RO/DI system but have not yet been able to produce any water because there is a leak in one joint that seems to be impossible to fix. I've tightened it as much as possible and then tried sealing it with silicone, but the leak persists. Is it more likely that there's a problem with the unit, or that I'm doing something wrong? Do you have any suggestions? <have you used plumbers (Teflon) tape on the threaded fittings? Really the best solution... silicone is unreliable for sealing threads. Do hope this does the trick... kindly, Anthony> Thanks for any suggestions, Ann

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 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>

Water prep question I have a saltwater tank which is doing fairly well except for a phosphate problem I am having. I have a 2-stage Kent water RO system which doesn't appear to get the phosphate (or at least enough) out of my water as I prepare it for addition to my aquarium. Is there something I could either add to my RO system to reduce phosphates? Something I can add to my tank? Use distilled water from the store? I don't have any better sources than this. <First, make sure your prefilters are getting changed on their recommended schedule. If you continue to have problems look into add on deionization cartridges.> Thanks for your help, Dave <You are welcome. -Steven Pro>

Preparation of RO Water Hi guys! <Steven Pro this morning.> Question: I just bought a good quality RO unit for my new 180 gallon Fish only tank. <A wise investment.> I have 2 connecting sumps, 1 for the Wet/Dry and 1 for the Skimmer & Chiller (about 48" X 12" of sump space). There appears to be a substantial amount of evaporation each day, (approx. 3-4 cups worth) since I set up this tank. <3-4 cups is not too bad. My 55 losses 1/2 gallon daily.> Each day, I have been adding the RO water directly to the sumps from the RO unit without preparing it first. Is this a bad thing to do even on a tank of this size? <Yes> I was told by someone that it's ok to do this, the RO water will take on the alkalinity, salinity and temperature of the tank water within minutes. <The salinity and temperature will not be greatly affected if the amount of water added is small but unaerated RO water will consume (for lack of a better word) your alkalinity. You should aerate first to drive off the CO2 in any purified water source.> I was told by someone else that the RO water should not be added directed to the tank, may cause a PH swing or even affect the temperature since my RO water runs kind of cold. <Depending on how much added. 3-4 cups daily at 60F is not going to be a big deal on a 180, but if you miss a few days and add several gallons at once, yes could be a problem.> I was also told RO water needs to be aerated & buffered overnight before introduced to the tank. <Correct> I am was hoping someone could tell me what the BEST procedure would be for topping off a tank of this size with RO water. <Aerate and heat prior to use, 8 hours as a minimum, no need for anything over 24 other than for keeping it ready.> I was looking through the WWM site for information about preparing RO top off water but I could locate any facts. Thanks for your support. I bought the Ebo-Jager heaters & the DAS Skimmer based on your recommendations. The heaters appear to be real accurate and the Skimmer was producing waste within 2-3 hours! <Glad to hear it.> Look forward to hearing from you guys. Thanks again! <You are welcome. -Steven Pro>

Alternatives to RO/DI <<JasonC here, Bob has gone diving somewhere tropical>> Good Day and happy recovery from the overeating I'm sure you did during the Thanksgiving holiday (I sure did!). My question is regarding the aging of saltwater after mixing. Currently, I mix my water well in advance (up to several weeks) and circulate with a powerhead in the garage. My questions are these: Is there a problem with stagnation when mixing the water this far in advance? I have never noticed any odor, or any measurable chemical impurity (ammonia, no2, no3). I have about 10 lbs of live sand (probably not really live any more) in my mix container. <<not as long as you keep a pump circulating the water>> I do not use r/o water. If I add activated carbon in a cartridge to the powerhead in my pre-mixed water, should I expect an appreciable decrease in phosphate/silicate levels, thereby seeing a decrease in diatom growth after water changes. <<probably not - activated carbon isn't really known for removing either of the two which is why the RO/DI market exists. In fact, some brands of carbon are noted for leaching phosphate a byproduct of manufacture, so pick your brand carefully. You can fill your head with carbon errata at http://www.wetwebmedia.com/chemFiltrMar.htm >> Is there a product that I would be better suited to use for the above mentioned phosphate/silicate removal? <<an RO/DI filter>> On another note, I have a Sebae anemone that I purchased about 3 weeks ago. It seems to be doing well. Currently it is situated with it's foot deep into a crevice in the LR, and it's tentacles showing during the majority of the light cycle. I also purchased a tomato clown to hopefully be a symbiont with the Sebae. It has been about 2 weeks since the addition of the tomato and just yesterday I noticed him rubbing against the tips of the anemone. Naturally I was thrilled and went to take a close look. The tomato proceeded to run and hide. Bummer! Hopefully this is the beginning of something special. Thanks for your insight. Jason Harris <<your patience will pay off. Good luck, J -->> By the way, my yellow tang, tomato clown, and striped damsel really LOVE Nori! That stuff is so much easier to deal with than romaine lettuce. <<also much better nutritionally for fish who would never encounter romaine in the wild. Cheers.>>

Questions about RO/DI Hi, <<Hello, JasonC here standing in for Bob while he is away diving.>> I'm starting my first saltwater reef tank, 92 gallons, should I use treated tapwater or RO water (is RO worth the extra money?  Thanks, Ed <<The compelling reason to switch to RO water is usually based on some problem in the tap water that isn't being addressed by standard water treatments - things like high phosphates, silicates, etc. Do check the following link on the WWM site - http://www.wetwebmedia.com/water4maruse.htm Cheers, J -- >>

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>

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>

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>

Mas una vez! One more time!!!!! RO vs. Tapwater Hello all, I am going CRAZY over here at the Cape with my RO unit! I know I have asked this question before, (To RO or not to RO?) BUT, I'm still not straight. I have been wanting to do a water change for weeks now, poor fish! Today, I finally bought the connection I needed to hook up my RO unit . Well, ..it developed a leak! I brought it to another sink, it started to leak too. I guess the plumbing in the house just can't take the pressure of RO units. This is so frustrating to say the least. Can you honestly tell me that if I do a water change with tap water, it will hurt my reef tank? At worst, maybe an algae bloom? <Yes, at worst an algae bloom. For every nutrient you put into the system, it must be taken up by the animals or removed later. I would keep trying to get the RO to work, but doing a few water changes with tapwater is better than not doing any water changes. Please buy a good quality water conditioner/dechlorinator and use as per instructions.> Our local water guy just came to the door to hand deliver the water analysis for the town. Cool huh? Although I don't understand all the numbers, at least if you want to ask me what's in my water. I can tell you. As a matter of fact, I'm going to scan it in and attach it to this letter, then maybe you can better tell me if my water is good to use from the tap. <Your water is acid and not very well buffered, so when you get the water conditioner, pick up some buffer too. The report does not mention nitrate or phosphate. This would give you an idea about potential algae blooms. -Steven Pro> Thank you so much I am going nuts over here! Pamela

R/O or No? Okay, who are you, Steve, Anthony, or Robert???  <You got Steven today.> Doesn't really matter, I think you all know your stuff. <Thank you kindly.> I'm the one with the ugly tank, <I would not say that. Most beginners make many mistakes. At least you have the courage to seek out the truth and to correct your problems.> well, I guess it has potential. I promise, I will upgrade my little Skilter, in the mean time, I want to ask about the use of RO water. What are the criteria for using one? <I prefer to use purified water whenever possible. It stops some headaches and minimizes the variables when looking to diagnose problems.> Originally, my reason was because I was reading about silicates in tap water, which would lead to unwanted algae, DIATOMS!! And if you recall my last letter, out of your million and a half, that was my problem,... diatoms. <Diatoms are a fairly routine problem/occurrence.> Are you following me? <I hope so.> I put off and put off water changes because I have to hook up the RO unit, then wait at least 3 days before I have enough water made for a change ( yes, I bought the cheap unit!). <Temperature has an effect on the performance of RO units. Perhaps your will speed up once the weather improves and your tapwater warms. Always use just cold water to feed the RO.> I have a 55 gal. I miss the fresh water days when I would just hook up the Python and let 'er rip! Do water changes REALLY have to be this complicated? On a limited budget, please! <You can still use the Python to drain water. I use a 30 Rubbermaid garbage can to hold my purified water. It is allowed to aerate and heat first. Then salt and buffer are added and allowed to mix. I then use a pump to send water back to the main tank.> Thanks! Pamela

Mo' R/O Rubbermaid huh? Well, that's cheap enough. But where do you keep this amount of water? Surely not next to the tank!  <My tanks are in my family room. I keep the new water in my laundry room, which is beside the family room. The Rubbermaid is about 20 feet from the tank.> UGH!....... AND, just as important, the pump,...... what do you use and are these units just a bit costly? <I use a Mag-Drive 500. I do aquarium maintenance for a living so I always have a plethora of pumps, hoses, heaters, etc.> Yes, I am a beginner for sure. I thought with the 20 some years raising so many fresh water species, that I would at least know SOMETHING! But I feel like such a beginner. For starters, I ALWAYS. used a UG filter, now I guess they're a bit primitive in reefs. That took a bit of convincing. And all this talk about sumps, overflows, pumps, plenums (sp?) ahhh, so much to learn. And I don't want my livestock to suffer as I learn, understand? <There is always something new to learn in this hobby. I learn something just about everyday.> Well, thank you for your time Steve. <You are very welcome, Pamela.> Pamela <Steven Pro>

Using well water Mr. Fenner, You had a person saying that his pH was 7.5 and NO3 zip. I am on a well and I can say do not trust one reading from one day to the next. <Good point> If you have heavy rain storm or no rain for a while it can change that fast. He should, I feel do a test for everything just as if testing tank water. This is extreme, but when hurricane Floyd hit Jersey, three of my friends had to have new wells put in for one reason or another. One of them had water that smelled so bad you almost got sick. It was such heavy rain they think the underground steams got diverted, blocked or just fouled their wells. I had to a softener knock pH so far out of whack that it ate the piping and lost about 100 bucks in three days because of it. <Wowzah!> So from my own experience, I don't trust well water. It is not worth the chance, just my opinion. <Thank you for this input. Will post. Bob Fenner>

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>

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

New 55g tank, ro/di water confusion!!! ... Hi there. Thank you in advance for any insight you can give me here. I have read so much conflicting info regarding ro/di yes or no??  <Mmm, depends on the quality of the source water, your perceived and real needs...> I am tempted to buy a unit, but in the same sense and tempted to go without a unit and see if I would do fine with tap water and save myself the money and trouble of ro/di initial costs and replacement filters. I am setting up a 55g will-be-reef tank. Is ro/di necessary? Is just plain tap okay in most cases? <I use tapwater in most applications, but a reverse osmosis unit for cooking, drinking water purposes... and on more delicate plants. Our tapwater is politely called "liquid rock"... some 500 or so ppm of total dissolved solids...> If so, what can I ask the water company the results of to determine if my water will be okay?  <Sure> Also, I have seen several people say only RO or only DI is fine. Ugh, so confused!!  <Read over the internet what your choices are here, the rationale for them. I would use only R.O.... Please read: http://www.wetwebmedia.com/water4maruse.htm and the FAQs beyond> Please help. I also have to figure out some way to dose Kalk into this tank, I will not have a sump, so I cannot use a gravity fed system, must use something that will pump the Kalk upward to the tank. Or, maybe I could just use the Kent gravity dripper during the night hours and go w/o Kalk during the day? I don't want that ugly Kalk dripper in plain sight during the day. So many many things, and I still have to modify my canopy. Thanks for your help!! Great website! Angela <Do search, read through the supplement, calcium sections on WWM again. Don't use Kalkwasser... at the very least develop a "two solution" supplement habit. 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

Tap Water Bob, Sounds like you had a good dive trip; am looking forward to some of your new experiences/pictures showing up in WWM material in the future.  <Me too... as I catch up! Yikes> I have a question that you may be able to help me with which could save me a little money. I am moving and the new tap water has the following characteristics: Nitrates 1.3ppm, Phosphates 0, Silica's 10ppm, Sulfates 51ppm, and Chlorides 36ppm (water company gave me this info as of yesterday) . When I store/age my water for a week, will this remove or at least settle out the silicates; <Likely not much, sufficiently...> I don't want to deal with the diatoms but also don't want to buy a filter/purifier. Do you foresee any other problems using water at these levels if it is aged and aerated for a week? <Mmm, some diatom over-growth... at first at least... you can develop/use countervailing strategies... growing macro-algae, a reverse-daylight photosynthesis sump... or even continuously lit one...> Thanks for your help and get some of those pictures out to us; we all don't live/have the traveling life and needs to live vicariously through pictures and a small aquarium system. <I understand... invidiously. Am placing one daily on the "New/Daily FAQs Page"... and on to articles, FAQs headers as I go through, label, scan, add to articles, PowerPoint presentations... and Zo and Jas are going to reveal how to send out to more than Billy.G will allow me on a more-automated basis... soon. Bob Fenner> Sincerely, Mike

Additives for RO water Bob, I have purchased a Kent Maxxima Hi-S RO/DI 60 gpd system. This will be my first experience using RO water in my reef tanks (long overdue). Is it necessary to use additives, such as, Kent OSMO Prep or is salt mix sufficient? <The salt mix (along with foods, what comes into solution from decor, substrate...) is likely fine... I would monitor and augment alkalinity and biominerals (Calcium, Magnesium principally) if you have invertebrates, particularly mineralizing types. Bob Fenner> Thanks

Pond water I am setting up a marine aquarium and I have pond water for my home. I share it with my neighbor and he adds the chemicals to the pond. He hasn't added any copper sulfate in years but he does add a bluing agent to keep the algae down. It does come thru our water system and our water is a little blue. Will this filter out and will it cause any harm to fish and invertebrates. <Do check with your neighbor re this bluing agents make-up... It does sound like "Aquashade", an alfazarin dye compound... which is chemically harmless... and can be taken out with activated carbon... or better, with a reverse osmosis device that incorporates a carbon contactor enroute. Bob Fenner> Thank you, Bill Baker

Treating well water Robert, << Not Robert, Jason C doing his best Robert Fenner impersonation, practicing for Bob's upcoming dive trip. >> Thanks for working on a great web site, lots of info here. I am sick of hulling in water for my 110 L and 190 L tanks and now my wife wants a bigger one.  << builds character ;-) >>  I want to get a treatment system for my well water. It is quit soft (25.1 mg/L) and not much iron (0.14 mg/L) Every thing is quite good except high salts (579 mg/L chloride + 1840 mg/L TDS). We are looking at an RO system but I am unsure how low these need to be to become acceptable. We have Balas and Australian rainbows and some tetras. Dow makes a brackish filter that operates at medium presser (15 bar) and has a 99.5 rejection of salts. Do I need to go to this kind of treatment or would removing 80 or 90% of the salts be adequate?  << from a purely statistical standpoint, 90% is outside of the first "standard deviation" which means 90% probably isn't quite enough. Considering your high level of PDS and TDS, I would think that the 10% that would leak-through would still present itself as a higher-than-normal concentration of things you don't need/want. I am unfamiliar with the Dow model, but perhaps just a bare-bones RO which gets you the 99% salt-rejection and then some additional additives to return hardness, etc to the water. Since Bob is still in town, I'm sure he will also reply to this in the event that I am way off-base. >> Thanks........ Colin << you are quite welcome, cheers. J-- >>

Re: Guess what? (tank repair, RO run-in period) Hi Bob, So far, so good. All the fish are fine and the soft corals made it okay. I did lose the feather duster starfish and a hard coral. They sat in buckets for 2 days. I guess that was to long for them? <Yes> I received my RO unit yesterday. I have started it off and will let it run for a few days, before I start using it for the fish. <A few hours is long enough> As soon as I get a chance to prepare the pictures I will let you know. Again, many thanks for your help. It is much appreciated :) Warmest regards, Lucien Cinc <Be chatting. Bob Fenner>

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>

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

Many roads to aquarium success I have two small (46g & 30g) tanks with live sand and live rock. When the water levels get low, I add just a gallon of straight distilled water. <Reverse osmosis would be fine, cheaper> I don't have regular stand-by salt water mixed and ready to go. When I do my 5% water changes every three weeks then I use saltwater that I make fresh. Is it harmful to a system to be just dumping in water like that? <Not very harmful... five percent is not much> I have seen no visible signs of harm, my tanks have been up and running for almost a year with no livestock problems. I run powerheads and powerful skimmers only. <Your success is all that is important, not specific methodologies. Bob Fenner>

Too much Caulerpa and R/O maintenance Dear Bob, It's Howard again celebrating a year of the joy of reef keeping. As usual I have couple of questions as I strive for perfect conditions and perfect water. Still haven't lost a fish. <Ah! Good for you.> How does one know when a R/O unit needs servicing (as everything else in a system does)? Mine has been in use a year and has probably processed 1000 gallons or so. There is plenty of flow, I'm just wondering if it is getting all the bad stuff out. I don't think my testing ability shows the small concentrations that might cause trouble. <Good question. Most folks I bet just taste a difference in the produced water... or figure it's time. But there are simple water quality tests, like conductivity (some water softening, reverse osmosis units come with a light bulb arrangement... with the light "coming on" as the amount of charged particles in the water passing between its electrodes increases)... You can test for total dissolved solids and more as well...> Is it possible to have too much Caulerpa in a refugium? <Yes... as in when it blocks the light too much for the material below it, or impedes water flow... or removes/bioaccumulates too much nutrient you want to go to livestock photosynthates...> I flow about 200 gallons per hour directly from the show tank to the refugium. The 20 gallon refugium is now totally packed with plant growth and producing lots of amphipods. I figure the more I have the more nutrients will be removed and the more oxygen will be produced. is that right? Or is there a down side to too much? <If you see too much dying below, remove some of the Caulerpa...> God bless America, Howard <Be chatting my friend. Bob Fenner>

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.

Kent marine maxima 24 gpd ro/di I know this may be a silly question but here it is I need to replace cartridges have replaced mixed bed resin cartridge but not carbon or TFC membrane. have made at least 3000 gal of water system is at least 3 years old. what cartridge would you replace and in what order would you put them I have lost my directions the system has three canisters with TFC membrane on top 1carbon block prefilter (which does not look dirty) <Do replace it anyway... very important physically and chemically to remove what you can before going further with water> 2 blue jelly looking cartidge.3 mixed bed resin high silicate removal. 1 and 2 came with unit. after looking in pet warehse not sure I installed these correctly. THANKS FOR YOUR HELP. ROCKMAN <Do contact Kent Marine re these units. See the www.WetWebMedia.com site for their URL.... "filter parts" on Kent's site. Bob Fenner>

Re: Kent marine maxima 24 gpd ro/di Robert, Change the pre filters at least every 6 months. The membrane is usually good for 2-4 years. I attached the instructions for the Maxxima RO/DI unit. If you need more information, please let me know. Thanks, John, Tech Dept. <Thanks mate. Will post to the WWM site. Bob Fenner>

Aging water/Skimmer, WWForum Hi Bob, Hope this message finds you in good spirits/health. Well, I'm back to pick your brain again. My question: would there be any benefits (pet-fish wise, not speaking of drinking, cooking, etc.) in getting an RO unit if I plan on aging my premixed saltwater at least a week in advance?  <Yes> I know you state that gases such as chloramine would be removed, and metals would settle, what about any phosphate in the water? <Most soluble phosphate removed by R.O.,  not by settling/aging> Sorry, I'm not much of a chemist. Also, I was planning on upgrading to a Turboflotor, but after reading through the skimmer selection FAQs, I got a little confused. Sometimes you stated that the Turboflotor needed to be plumbed to the overflow to work properly and that the powerhead was only for mixing air/water. Other times, you mentioned that the Turboflotor only needed the Rio2100 or equiv to work properly.  <Sorry to be confusing. The latter is the case... Aqua-Medic does make skimmers (Turboflotors) that are hang-on and in sump models... there are applications where connecting these to overflows make sense... not many though. And of course the hang ons operate AS overflows back into either main systems or auxiliary sumps/tanks.> If plumbing to the overflow is required, I think I would go with the Aqua-C Urchin Pro instead for ease of setup (little more money, less efficient?).  <A bit less efficient in most settings> Any clarification would be appreciated. By the way, the Wetweb forum is looking good. I hope everybody logs in and contributes! Thanks, and have a good week. <Me too. Be chatting my friend. Bob Fenner>

RO water Hi Bob. I just ordered a Kent RO unit and have a question. I always age the salt water I do water changes with, but is it okay to have the RO unit empty the water it makes right into the sump for water top-off, or should it be aged, also? Thanks in advance! <Good question... and no problem with "not aging" (i.e., I would just have it go "right into the sump" w/o storage... most all "bad stuff" that can be removed by storage will have been taken out by the contactor and RO parts of the unit. Bob Fenner> Jason

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

Treating Water for my Future Marine Tank! Help! I just moved into a new house. I'm planning on buying a used 135-gallon tank (I wrote to you about this before), and I am starting to evaluate costs. When I set up my little 10-gallon freshwater, I bought distilled water to start with. Unfortunately, I don't have the cash to spend on 130+ gallons of distilled water! The obvious solution is to use tap water and age it appropriately. <Whoa! Hold on... other possibilities are likely more practical... Do read over the "Water" and "Seawater" use sections on our site: www.WetWebMedia.com... Likely you will find a reverse-osmosis system a very good investment (inexpensive, easy to use) for your aquatic and drinking/cooking uses> My new house has well water, so I don't have to worry about chlorine too much. The problem is that our tap water smells like eggs (obviously a sulfur thing). Not only is this nasty when I take a shower, I'm kind of worried about what it might do to the fish. How can I deal with this? <A few ways... I would have your "water district" test your water, give you their input here... and what company's in your area that provide residential water treatment give you bids on the contactor technology they lease> I don't have a lot of room for giant tubs to age the stuff, and I do have a very curious dog who would love to stick his head (and slobber) into any large vat of water. HELP! Sincerely, Gina  <No worries mate... do this bit of investigating, reading, and we'll be chatting. 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...>

Water Changes I've done five 25% water changes this week. Ca is now at 360 and Alk at 4.5 meq/L. I'm thinking that at this point, I've probably reached the point of diminishing returns as far as water changes go. <Practically so> The Ca level has come up solely from the water changes, by adding whatever Ca is ambient in the Instant Ocean, as I have not been supplementing during this process. I had originally planned on needing eight water changes--however, I'm thinking at this point that further water changes will have minimal effect and probably be more stressful on my livestock (and me. . .) than they're worth. Although the alk is still a little high, would you recommend additional water changes at this point? <Not really... agree with your rationale> I was reading some of the FAQs today and in one answer, you mentioned that running activated carbon in the filter path will increase light transmission. Is this from just having "cleaner" water and fewer contaminants?  <Yes... it is surprising how much different/improved light transmission is with dissolved "color" and particulates removed... a matter of science... and real trouble can be had by changing this too much too soon...> I've added a filter bag to my system with activated carbon--although I'm still trying to find the best way to cram it down in one of the prefilter boxes. Is there any downside to running activated carbon all the time, or should this just be done occasionally?  <Some downside... but not practically so... AC gets "used up" very quickly (minutes to hours)...> I know plenty of people that run activated carbon 24/7, however, for some reason I keep thinking that in one of your answers to a FAQ on WWM, you mentioned or implied that it shouldn't be run 24/7. Can you straighten me out on this one? <Gets clogged in some applications, but can be "left in place"... with new/old material being in place...oldest being replaced cyclically... as bio-filter substrate...> One final issue. I moved a finger leather from one side of the tank to the other, necessitated by the addition of a new powerhead that changed the flow at the old location. The finger leather's new location is on a piece of LR which put its base about 4 inches above and 4 inches behind the top of a Goniopora. The Goniopora seemed to not be doing as well since its new neighbor moved in. I suspected that the finger leather was "poisoning" it--so I moved the flower pot to the opposite end of the tank, more by itself. This also contributed to my decision to add some activated carbon to the system. Does this sound reasonable? <Yes> The Goniopora had been in the exact same location since it was put into the tank 2 1/2 months ago, and had always done fine with polyps extended 4-5" on the sides. It hasn't been extending its polyps much since the finger leather moved closer. Another potential cause, however, is the anionic imbalance--and the fact that Ca got to 210 ppm, which happened at about the same time the finger leather moved nearer. So my final question is whether the changes in the Goniopora would more likely be related to the ionic imbalance as opposed to the proximity of the leather coral--or whether the ionic imbalance/calcium drop just added insult to injury? <Both> I was reading the FAQs posted today--and the one regarding the trade show made me salivate! I'll be at La Quinta the first week of April--are there any good LFS's near there to gawk at? <Check out the yellow pages for the area... including the aquarium service companies and call on them ahead of your trip for input...> Thanks for your insight once again. --James D <No mention of the Cirrhilabrus luteovittatus pic? Hmm. Bob Fenner>

DI water and pH Hi Bob, How are you? You must get tons of emails a day! <Fine... and yes, quite a bit> If you recall, I have a 60G reef and for some reason, I just am not able to get the pH up, only at 8.0 using Salifert test kit. <No problem. Eight is fine> I just read an article regarding DI water for drinking and the article states the pH for DI can be as low as 5.8? Is this correct?  <Hmm, yes... initially...> What could I do to boast the pH? I am using SeaChem ReefBuilder and Reef Advantage for Alkalinity and pH control, Reef Crystal for salt, and TAP from Aquarium Pharm for water treatment. <... a few things... like adding carbonates, bicarbonates... in a few ways... None of which are advised (causes of troubles many times a day...). Could add an ozonizer, more aeration, some macro-algae... Please don't overreact here. Your current pH is fine> Thanks. Brian <Bob Fenner>

Well water Dear Mr. Fenner, I've written you before and I do hope I don't become a pain, but you are reliable and so quick to answer. Presently we have a 75 gallon with live rock, some corals, and a cleaner crew no fish due to a previous ich problem). We have recently purchased a 120 gallon tank and plan on transferring everything from the 75 to this one.  <Ah, good> I've read your opinion of city water, understandably, but we have well water. Is it just as bad?  <Hmm, biologically? Use-wise? Only you and your water quality test lab can tell for sure... If you have a concern, do get/use a reverse osmosis unit for pet-fish and cooking/drinking uses...> We are going to transfer the water from the 75, so we are going to have to make up some water to reach 120. Do we have to let the mix sit for a week, being its well and not city water?  <Don't "have to"... but pre-mixing is suggested (by myself)... And not so "big a deal" if this is just "additional water" (as opposed to all-new)> And then how long before we can add fish? ( I have the CUTEST Red Lipped Blenny, with personality, in the quarantine that I am just dying to put into the bigger tank). <Patience is a big virtue, as you know...> Also, we have a ETS Reef Devil 3 for a protein skimmer on the 75 and the stand for the 120 is going to have to be modified for it to fit. IYO, would it be worth it to modify, or better to get this Turboflotor you have been raving about? <Hmm, both are good products, appropriate for the application... Can you use the ETS elsewhere (like the 75?)... > After reading all the recommendations you have been giving for this skimmer, I expected it to cost a fortune. I was surprised to see how cheap it is compared to some others I actually called up one company to make sure the price was what they said it was on their site).  <Yes, a nice group of people making them in Europe, and also reselling/distributing them here in the U.S.> Well that's all I can think of for now! Thanks so much, Mercedes <You're welcome my friend. Bob Fenner>

Distilled water Bob, I've been using distilled water with a auto doser for topping off my 75 gal tank. Is distilled water ok to use? I pulled this off a web site. <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> "This applies to distilled water in that you have an extremely low (if not zero) concentration of salts and other minerals in distilled water. A frog's cells, on the other hand are chock-full of salts and enzymes and minerals - in short, highly concentrated. The cell membrane of a frog cell, and indeed, one of any animal, is water-permeable, allowing the distilled water to cross over into the cells in an attempt to equalize the concentration of substances on either side of the cell wall. The pressure will build up more and more until the cell pops. If a frog is exposed to distilled water on a consistent basis, then it will eventually die. (BTW: the same goes for people [takes a while] and fish, the latter being the subject of a rather odd running joke in my biology class "The exploding goldfish") In summary, I would avoid the use of distilled water with any aquatic / semi aquatic species. Instead, look around at spring water. Artesian sources are usually a fairly safe source in my experience. " <Not bunk... if you were keeping your livestock in just this water... however, your salt mix has plenty of ions, other dissolved solids... that don't leave solution... when the water otherwise evaporates... and that is what you're replacing> Can you tell me if this is bunk? And a simple question, will boxfish consume soft corals? <Sometimes, yes.> Look forward to reading the questions everyday. Thanks, Darren <Glad that we're connecting. 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>

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>

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>

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>

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>>

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