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FAQs on Deionizing, Ion-Exchange Source Water Filtration

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

Related Articles: Water Purification Using Reverse Osmosis. Water ChangesWater QualitySynthetic or Natural Seawater, Nitrates

The water in the ocean is not "pure"... Lemnalia sp. living in "muck".

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

DI and Prefilter Cartridges - 04/14/07 Hello, <<Howdy>> I was thinking about getting a deionization unit and have several prefilter units. <<Ok>> I was hoping to get the prefilter units from a home improvement store, and I was wondering if the common micron cartridges and carbon block cartridges for aquarium use would work for the canisters purchased at the home improvement store (standard whole house prefilter housings)? <<Indeed they will, and in many cases are one as the same...simply renamed/repacked for different sellers>> I was planning on having 5 stages in order.  5 micron sediment filter, 1 micron sediment filter, carbon block cartridge to remove up to 2 P.P.M., Poly-Filter, mixed bed deionization cartridge. <<Sounds fine, though adding an RO membrane filter ahead of the Poly-Filter and deionization cartridge will increase the life of the resins..."how much" being dependant on your source water.  But your proposed filter will also work fine as is>> I live in an area where we can drink our tap water. <<Ahh, I see...and me too!>> Do you think this would be a good filter? <<I do, though if it were me I would replace (combine) the 1-micron sediment filter and the carbon cartridge with simply a single 1-micron carbon block>> I also thought about maybe having 2 carbon block filter canisters? <<You could, but one will do nicely on its own>> Thanks for your time!  I appreciate all the help.      <<Happy to share.  EricR>> Re: Is DI enough? Juneau... the town, not Beetlejuice's Case Worker  11/30/06 Hi again, Thanks for the advice. Here is the City water report.  I don't know what most of this stuff is, so I hope it's the right information. <Mmm, you can easily look up each of these items... and they're probable implications... on the Net> I asked them about dissolved gasses in the water but they said they don't test for that. Can I? Do I need to? <Mmm, can have done, not likely useful here> As for what I'm shooting for: I jut want water for top-off. I plan on having hard and soft corals eventually with a few fish if they serve a purpose. Thanks again, Bill <The DI is likely going to be fine... along with the carbon contactor... A note: I would NOT drink/cook with this source water myself... ten ppm of NO3, the amount of listed analog of sanitizer (trihalomethanes), and upward measures of metals listed is too much... The cheaper route for your consumption is reverse osmosis... likely the same for your fish tank/s. Bob Fenner>

Question about RO waste water ... and DI set-up  11/18/06 Hello, Hope all is going well <Yes, thank you> I currently have a 125 gallon reef tank... no problems to report right now. All corals, fish and inverts growing doing well. I use DI water for water changes and top off. I made a 3 stage filter from parts at my local hardware store. The unit consists of a 1 micron carbon block filter and 2 mixed be DI cartridges. I order these from Waterfiltersonline.com and pay about 10 bucks for carbon and 30 bucks for each DI cartridge. <Sounds good> The website also sells Kent marine replacement membranes and filters. <Thank you for this lead, info.> I was wondering if it would be better for my reef and my wallet if I purchase a RODI unit and pass the brine waste water through my homemade filter system and back into the RODI? <Mmm, other than the venting issue (I see mentioned below)... is your water that expensive?> It may sound crazy, but I do not have a drain near by. I know I run the risk of fouling the membrane much earlier if I do this, but I only get 2 or 3 30 gallon water changes with the current setup. <? Is this to say, the membranes currently in use "clog" or otherwise become non-functional with just sixty or so gallons of DI water produced? Something is off here... I would be having your source water checked (may be done so routinely by your water district... do call them per the number on your billing)... and then the supplier of the DIY gear for advice on setting all this up properly. It may be that another in-line filter ahead of the carbon will save your membranes... I would not "re-route" RO treated water back to/through a DI... but might well set these two technologies up in series... the RO ahead of the DI... The "waste" water I would find a way to vent to your garden, elsewhere> It only lasts about 1 month. Can you tell me if this would work or not or is it a waste of time and more money...Thanks John <As stated, there is "something" amiss here... I doubt your source water is that much at fault in clogging/ruining the DI... Bob Fenner> Converting RO/DI to just DI 10/24/06 Hi All, <Hello> I'm upgrading from a 90ga to a 600ga tank. I've been using a 4-stage RO/DI system for treating the water (1 micron sediment prefilter, 0.5 micron carbon prefilter, R/O, and finally a DI cartridge). I do a 10% water change weekly. <Good> The amount of waste water from the RO process has always bothered me; however, I wanted the best from my reef inhabitants. Now that I'm increasing the size of the tank, the waste water will be enormous. I know from reading this site that you're not fans of R/O for the same reason. <Personally I am a big fan.>  I do want to be a good steward of the earth's resources. <Choice to be made here.>  Can I just bypass the RO unit? Will this have a substantially negative impact water quality? <Yes> Should I also eliminate the DI cartridge and run the output through a two-stage Kati-Ani unit? I eager await your response. Michael <From an environmental point of view I believe the RO/DI unit is much better, at least in the area I live in that has lots of fresh water and processes waste water and returns it to the Great Lakes.  I can tell you from experience that you will only get 20-25 gallons of quality water out of a DI only unit, then this unit has to go in the garbage, back to a land fill where it will sit for many years/decades. Find a use for the waste water from the RO unit, watering plants/garden, washing cloths, etc rather than through out plastic cylinders full of the same stuff that goes out with the waste water.> <Chris>

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>>

D/I water ph   7/7/06 Hi good folks at WWM. Could I please ask a dumb question? Seems like the more I learn the more I don't know. Any one else have this problem or am I not as smart as I thought? Re. using de-ionized water... It should come out with a ph around 5.5 correct? <Mmm... not this low with most makes/models> My tap water is a high 8.4... Should I try to mix these to a desired ph for freshwater... about 7.5 or so. or use all D/I water and buffer and raise accordingly? Thanks so much....DR <Good question. A very good practice is to store, aerate the treated water... see/measure consequent pH, alkalinity a day or more later... adjust this here before using. Possibly by mixing/blending some original tap/source water, but maybe through commercial buffer products, other means. Bob Fenner>

Using D/I Water With Fish   7/7/06 Hi Bob...According to what I have read, D/I water pH can't be measured due to the absence of anions or cations. Will the pH be able to be read after a couple of days of aeration in a container? < Usually the water picks up some CO2 from the air and has a slightly acidic pH.> If so then maybe check it then and add either buffer or tap water to get the desired ph and alk? <I would start by adding some tap water and see if it can be managed that way. Buffers are needed if you are going to be working with fish or organisms that require a very narrow or exact pH and hardness levels.> Which would you recommend? I hate adding chemicals to my tanks. They are not natural and most have a  problem that comes with any good effects. Thanks again...DR < If you already have an established aquarium with tap water, then outside the tank I would use one part D/I to 5 parts tap water. Use this water to do your water changes. See how the fish react to it. Fish usually don't like big radical changes in water chemistry. Continue to monitor the water chemistry. If you need softer water then you can always add more D/I water to the ratios. One word of advice. Once you get your water to where you want it, it will be different from that at the local fish store. Chances are that your local fish store will be using straight tap water. Some fish may have difficulty making the adjustment. This is why you will need a quarantine tank to make sure that the new fish is relatively free of parasites and then you can slowly match up the water between the two tanks.-Chuck>

Deionization Question Hello Wet web, <Hello Mike> Quick question. What kind of impurities does a DI system not get out of the water? <DI units consist of two ion exchange resins.  The DI process removes calcium, magnesium and other positive metallic ions.  Basically what you have is mineral free water.> Are they necessary to get out? <Depends on your source water quality.> Can I get away with using just a DI unit instead of a RO/DI? <Yes, depending on your source water quality.  If nitrates/phosphates are present, you will need to RO.  DI systems alone are normally used where high mineral content is in the water.> Thanks for the help <You're welcome.  James (Salty Dog)>    Mike

Deionization Options - 02/04/06  - 2/4/2006 Hello There, <<Hello>> Pretty amazing FAQ area you have there. <<The cumulative efforts of many good people.>> I will make this quick.  I have a small Kold Ster-il unit.  I am looking to add a DI unit after it.  However, none of the DI units I have come across have the 1 inch connection that would enable easy connectivity from the Kold Ster-il.  What do you suggest? <<Plastic or nylon adapters should be easy enough to find (Lowe's/Home Depot)>> Should I just purchase another ten-inch canister (clear), 3/4" and a DI media of some sort to put in there? <<A popular solution.  Most DI cartridges are designed just for this purpose.>> If (yes) which DI media do you suggest? <<I prefer the mixed-bed color-changing resins.  The non color-changing resins are a few dollars cheaper, and easy enough to use if you have a TDS meter to determine when they are exhausted.  You can also save a few bucks in the long-term by purchasing a refillable cartridge and using 'bulk' resin.>> I prefer this DI media to be as simple as possible for replacement if possible.  What do you think are my best options? <<Have a look at this site...lots of good options and good prices.   http://www.thefilterguys.biz/index.htm >> If (no) then what?  Maybe? - http://www.purewaterplanet.com/aspages/getproduct.asp?item=875 <<Pricey, but yes, another possibility.>> Does that media above need to be recharged or do I just replace the media when it turns color? <<Some can be recharged (can be a messy process) but many folks find it's not worth the hassle on small units such as these.>> I am not that savvy on DI and why there are chemicals for recharging if media like this exists. <<People with large Cation/Anion (Kati-Ani) units used as their sole source of water filtration do find it more economical to 'recharge' their resins.>> Please excuse my ignorance on the area of DI water purification. <<Easily remedied with more research/reading.>> I appreciate your time, help and advice. Kind regards, Stephen <<Welcome, EricR>>

Deionizing units 01-06-06 Hi Anthony, <Travis here with you today.> I was reading a thread on RC and noticed you have left, anyway, I have a couple of quick questions about DI units and there operation. OK, basically I have been read and researching these and I just have a few quick questions, I'll just make sure I understand it correctly. <Always a good idea to clarify one's understanding.> Resins in the DI units are called "anion", and they remove negatively charged ions from the water, and "cation" which removes positively charged ions. Those 2 types of resins make the basis of a Di unit. Correct? <Correct> My first question is, Any contaminant such as pesticides, that are (neutrally charged), will not be removed. Is that true? <This is correct.> Also I have learnt that the units should never be used to full capacity, since they could begin to release some of the contaminants they have removed back into the water. Is that true? <This is also true, just as it is true with carbon and other water purification substrates. Travis> Deionization units (what a surprise)  12/16/05 Hello all, <Good Morning Peter> Thank you for your valuable time. <You're welcome> While researching your site and others on this subject I e-mailed SpectraPure for info on selecting one of their DI units. Well, I was quite surprised with their reply and wanted your esteemed opinion on it, please. Here is Mr. Charles Gibbs' , Sr. Applications Engineer reply in quotes. " Peter, DI resins are extremely effective when installed after an RO membrane but DI resins do not work efficiently in tap water and we do not recommend "tap water DI systems". Tap water DI can be expensive to maintain, the product water quality is poor at best, and tap water DI is not extremely effective at removing silica, phosphate and nitrate. The purification systems that we have engineered deliver the highest possible water quality at the most economical cost per gallon. An RO and DI combination system is still the most effective, efficient, and economical means of removing contaminants in most applications. If you were to decide to use an RO system prior to the DI, we will be able to help you; if you decide that tap water DI is your preferred method, we would choose not to supply that equipment. NOTE: We may at some point in the future offer a tap water DI but it would not be engineered like any of the existing DI resins that are on the market today and even then, it still would not offer all of the advantages of an RO/DI combination system. Please feel free to call us if you would like additional assistance. Thank you for contacting SpectraPure. Charles Gibbs Sr. Applications Engineer SpectraPure Inc." I am surprised and confused by this reply. Especially since reading your recommendations on DI units. Please let me know your take on this, OK? <Peter, DI units that I'm aware of are all "add-ons", that is they need to be placed after an RO unit.  Aquarium Pharm makes a mixed resin bed filter that hooks right up to the faucet.  These do a reasonably good job, but the cost per gallon of filtered water is not reasonable, anywhere from $.22 to $1.12 per gallon.  The filter runs around $28 and is good for 25 to 125 gallons depending on your water conditions.  Replacement filters run around $15 each.  Better to go with RO/DI and have much purer water.  James (Salty Dog)> Thank you, <You're welcome> Peter Lakewood, Ca

Re: Deionization units (what a surprise)  12/17/05 Hi James, And thank you for your quick reply! I understand that now, but DI units alone ARE recommended in your answers. It may be Mr. Fenner (maybe Mr. Calfo) that strongly recommend them to avoid the "obscene waste of water" that RO produces. I think those answer coupled with the SpectraPure communication are definitely in conflict. Yes??? <Peter, the DI units will purify water when used as a stand alone.  The downside to this is that the resins will be exhausted much more quickly in this regard since they are removing much more impurities than they would if being used as a add on after the RO.  In my opinion, used as a stand alone, they are not cost effective.  That's another reason why, on average, you only get about 50 gallons of purified water from the Aquarium Pharm unit before the cartridge has to be replaced.  Hope this clears it up for you.  Happy Holidays.  James (Salty Dog)> Thanks again James <You're most welcome> Peter

How to recharge a deionizer I've looked and looked but haven't found anyone who will lay out step by step how to recharge a deionizer. I know you first have to have one that is rechargeable. any help? thanks Brian <Mmmm, well... some resins are recharged with caustic substances... some with salts... Some can't be economically recharged by simple soaking (require high pressure, temperature in the process). My real advice is to contact the manufacturer or barring this, find out the name of the ion-exchange resins in your unit and search the Net, reference works in a large (college) library re this issue. Bob Fenner>

- Deionization Systems - Hi all at WetWeb, Could you give me information on possible deionization systems that are available commercially and your opinion of them? <Hmm... difficult task. There are simply too many brands and too many becoming available to know them all... for the most part all use the same technology. Doubt there are many true differences between the various units available to the hobbyist.> I will soon be expanding my coral propagation biz, and I'm looking at the deionization factor rather than going with RO again due to the great amount of waste water generated by RO systems. <Would work with a commercial water purification company to design/install this.> Many thanks, Peggy AquaCorals <Cheers, J -- >

Water Softeners Hello!  I love this site (so much information!) but I can't seem to find the answer to my question. Exactly WHY are water softeners (the kind that uses salt exchange) not recommended for freshwater tanks? I have a friend who I have tried to warn against this but she won't accept just "it accumulates chloride ions"....and sometimes I wonder too....(here's the dummy part....we are talking about salt right?) because if you're using the water for water changes, you would be removing as much as you are putting in, right? Not good I'm sure for top offs, but otherwise wouldn't the levels stay the same? And if this is true, then the salt level in your tank couldn't be that high could it? Around the same level as people who use the teaspoon of salt per gallon thing?  Thanks for taking the time to explain this!! Barbara  < Ok here goes. The resin in water softeners uses the sodium (Na+) ions in the salt (NaCl) to exchange with the Calcium ions (Ca++) in the water. So now you water is not as hard but now it has lots of sodium which is not good for fish. To truly soften water you do need to remove the calcium and magnesium ions with a reverse osmosis unit that removes the hard water ions by forcing the water through a membrane that only allows the water molecules through and leaves the others behind. Another method would be deionization. The water runs through a two types of resins that attracts both the positively charged and negatively charged ions leaving essentially neutral water. Distilled water uses evaporation to leave the ions behind while it condenses into pure water. If you just added tap water all the time without doing water changes then the minerals in the water would accumulate and become higher than the water source, unless they were utilized by plants. This is an over simplification but this is how it works.-Chuck>

De-ionization recommendation 3/28/04 Hi all at WetWeb, <cheers> Could you give me information on possible deionization systems that are available commercially and your opinion of them?  I will soon be expanding my coral propagation biz, and I'm looking at the deionization factor rather than going with RO again due to the great amount of waste water generated by RO systems. <agreed very much. "tis what I did for my coral farm> Many thanks, Peggy Nelson.  AquaCorals <my long-standing fave (have bought 3 units in 10 years) is for the Kati Ani brand (the larger models simply go longer between recharges). Seek from Dr Fosters And Smith or Gwynnbrook Farms (MD discus hatchery). Anthony>\

Deionization systems 3/28/04 Hi Anthony, <hey, Peggy> Many thanks for your response on DI systems.  We will soon be moving to a location with more space for expansion of my coral propagation endeavor. It's very exciting.  My good friend, Penny, at AquaCorals in Maine, has had requests for wholesale purchases of tank-raised corals and has forwarded them to me for future response.  I look forward to the possibilities! <outstanding friendship/business... you will both go far in life with such healthy outlooks> Unfortunately, she and I are a long distance apart or would surely be working together! <ah, but the Internet in part bridges that gap amazingly> Thanks again for your response.  You are a good man. Peggy <thank you my friend... wishing you the very best. Anthony>  

AP tap water filter hello, I have been using the tap water filter for a while now and have been very impressed. but some say that the water quality isn't that great. what do you think? my water is relatively clean, although its very hard.  < We need to define terms here. Filters remove things from the water. Different filters remove different things and your impressions may depend on what things you are trying to remove from your water. If want to remove chlorine then a carbon filter will work fine for awhile and it will be better for your fish than water that has not been through a carbon filter. If you are keeping hard water fish such as rift lake cichlids then your water sounds perfectly fine and that is all the filtration you will need. If you want to soften your water by removing minerals then you need to go to an R.O., deionization, or distillation to remove these minerals for fishes that require softer more acidic water.-Chuck>  -Jared

R/O vs. DI 10/23/04 I look to your website for all of my information.  All your articles  and  FAQ's are invaluable, and I thank you for providing this service. <thanks kindly for saying so> I let my R/O membrane dry out (oopsie) while reconfiguring my reef  set-up.  A new membrane is about $90.  I saw a DI unit, namely the  Deion 200R, for about $200.  It claims that it wastes no water- needless to  say it caught my eye since my Kent R/O throws away 3 gallons for every gallon it  makes.  Hurts the wallet when the water bill comes. <agreed... and is simply wasteful at large. I prefer DI myself> Is this DI unit suitable for a reef tank?   <likely yes... but do ask to see the specs> If I'm going to spend 90  bucks, might as well spend a few buck more and save in the long run. <agreed. And do a keyword search for "DI" from the home page at WetWebMedia.Com for more info> Again, thank you for both your service and time. James Pruefer Prov, RI <all good... best of luck! Anthony>

- RO vs. DI - Hi Gents, I am in need of some education! <Me too.> I have a 70 gallon reef, 30 gallon sump, and just added an AquaSpacelight with 650watts.  So, I had to remove the hood and tank top covers, and as the summer hits, that water is leaving fast!  I'm probably going through ~10 gallons a week through evaporation.  The tank is doing the best it ever has with this setup and RO from LFS currently, lots of buckets. I also am using an Aqua-C EV-150 and DSB.   I have been successful (knock on wood) with Acropora, scallops, Gorgonia, some other SPS (not sure what exactly it is), a small polyped cup, plates, brains, and some Ricordea, orange/red/green polyps and other misc. non-stonies. Ok, to the question: I was about to buy a Hi-S 35 or 60 gpd RO/DI unit by Kent, then I reviewed all of your FAQs on this subject and have seen several different options, and opinions.  I like RO because it can get the water so clean and it has worked excellently so far, but I hate wasting that much water. <Then store the water - what comes out of the waste side of the RO is dechlorinated, and pretty much safe to drink. Save for watering plants or for use around the house. No one says you have to throw it away.> I don't know enough about De-I units to make an educated decision, and there doesn't seem to be much info on them out there, but some of you really like and have promoted their use.  Please help me understand the basic differences, and their advantages/drawbacks. <DI units are exactly that, and not much to explain - just a deionization cartridge.> How do you re-use the de-I units---do you have to replace media often? <That is the Big Deal (tm) - DI cartridges can be renewed but require the use of some hazardous materials. Personally I'd just swap out the cartridges - and how often will depend on the quality of your source water.> Can the De-I units get the same quality of water as an RO unit? <Really, defend types of filtration - suffice to say that the product water from each is "clean" but cleaned differently.> Is it good to run either RO OR De-I and not both together? <You can run both together, and this is not an uncommon configuration - I own an RO/DI filter, but no longer run the DI cartridge. DI after RO tends to deplete a good portion of the minerals in the water. Where I've been living for the last couple of years, the water is very hard, so I take advantage of that rather than having to re-add compounds that my water filter has taken out.> I understand that they're both options, but don't understand what to base my decisions on. <I'd work from the quality of your source water - if it is even close to good, you really can get away with throwing in some dechlorinator, mixing for a day or two and then adding salt. Heavily treated water or water high in particulates may need additional filtration.> Sorry for the vague e-mail, but I just haven't found enough info to make it a more educated question!  Any help would be greatly appreciated. (and if there is anything else you think I should change, please let me know!) Thanks, Scott <Cheers, J -- >

- RO vs. DI, Follow-up - Ok, a follow up question... I think I may have come up with a solution--maybe! <I may come up with an answer, maybe...> I dislike all the water waste of RO and can't really save it for later use, and don't want to remove all the "good" things in my water as it is very hard and of good ph.  Can I get two "add on" RO canisters, and only use a sediment filter and a carbon filter---no TFC or DI? <Sure.> I would like to know if that would take out some of the bad things by using the carbon and sediment filters, but not waste water due to not using the TFC filter, and also leave a lot the calcium? <Would take care of some of the particulates and chlorine.> If so, what else would this leave in my water? <Hard to say... would need to have the output tested to be certain.> Any good points or bad points to this proposition? <Not really.> Also, what kind of carbon filter would you recommend--1, 5, or 10 micron? <Slightly smaller than the prefiler you choose.> Or is this a waste of money and I should just leave everything in the water and dechlorinate it? <I'd try this route first if your source water is of decent quality - do you drink your tap water? If so, it's probably ok to use in your fishtank.> If the latter is your suggestion, can you recommend a good dechlorinator which won't set my skimmer on the fritz? <They all do this to an extent, and there's no real way to remedy it - have heard that Amquel does OK, but am not certain that it is a dechlorinator - check the bottle.> Thanks again, Scott <Cheers, J -- >

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>

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>

RO/DI Unit Hello WWM crew! A couple of questions; I'll try and make them as quick as possible. 1.) My tank has had some down time. I was having a terrible time with hair algae and got fed up with it and just left the tank alone for almost 4 months now. I didn't have an RO/DI unit and I think that my source water was the culprit. Now that I am making a little more money and have the means to get the right equipment I will be purchasing a Spectrapure 2000 65gpd unit soon. I've done no water changes during the down time and the tank looks like crap! I am planning to clean the algae off the glass and take the rocks out, scrub them off as best I can and add more substrate.  <sounds like a plan>  ( I only have about an inch and a half avg. depth ). I'll put the rocks back in and rearrange them. When I do this I want to make a large water change. <ok> Can I use distilled water as a substitute until I get the RO/DI unit and then do another large water change?  <you could but I would just use regular tap water with some dechlorinator added to it>  Should I just wait and use RO/DI?  <I would just use tap water for now until you get this>  Do you think that the algae will begin to die off after I replace most of the tank water with RO/DI water?  <depends... on how much you feed your fish and the dissolved organics in the aquarium> 2.) I need to upgrade my circulation system as well. I plan to buy a pre-made sump and use an Ampmaster 3000 as my main circulation. I think that I can plumb this pump into numerous returns and still have adequate water flow. If not I'll get the 3500. I do not have a drilled tank. I was thinking of getting 2 CPR 1600gph overflows to feed the sump. What are your opinions on this idea. Any other suggestions besides having the tank drilled ( that's really not a feasible option )?  <I would get the two CPR 1600 GPH pumps> I hope that I did not confuse you on the first topic! Hope to hear from you soon. I will definitely have more questions for you as I am planning to renovate the majority of my system.  <I look forward to it> Thank you,  Stephen Baker  <you're welcome, IanB>

-Recharging DI resin- hello all and happy long weekend- <Thanks, alas, it's all gone now...> I was hoping you could help me with a few questions regarding a Kati/Ani 2 set-up I just purchased from Dr. Fosters. I also purchased replacement color changing resins from  Spectrapure for this same unit. I am now thinking this was a lack of knowledge induced mistake. I hope I can return them, they were a bit expensive. Now that I have the Kati/Ani units in my hand it looks like they are a sealed unit except for a little plug on the front. I am now thinking that you do not replace the resins inside and you just recharge them instead. Is this correct? <I just throw mine out when they're depleted. If you want to recharge them, check out http://www.reefs.org/library/article/twp_recharge.html>Or can they be replaced somehow also? <I'm sure there's a way to dump what's inside and replace with what you've bought. Check and see if that plug is removable.> From what I have read, it looks like I would use lye and Muriatic acid. Do the  resins just get rinsed/soaked in these chemicals and  reused again? <The chemicals should not be reused> Do you know if the recharged resins retain their color changing ability as they are exhausted ? <Yep, that's how you tell that they're in good shape (they'll be the original color)> I am guessing, yes. The instructions that came with the units are printed in somewhat of a broken English that makes me a bit unsure about the process. For hook-up ,the instructions talk about using Kati/Ani for" total desalting of water" and how to hook up the units. It shows tap water entering through the  center of the Kati unit, then flows over to the center of the Ani unit and then out for storage. Is this the correct procedure? <I'm not sure how this brand goes together but you want all water to go through the resin without any possible bypass> I do not know what desalting means. <Just means stripping the water of all impurities> I apologize for all of the newbie questions regarding DI water but I do not want to make a mistake and hurt any of my longtime finned friends. <I hear ya, better safe than sorry!> Have a nice weekend and thank you for your time <Good luck! -Kevin>  Dennis

- RO/DI Water Smell? - Hi, <Hello, JasonC here...> I have read all the topics about my problem in the section, but I did not find anything similar to my problem. I appreciate if you could give me some advise about this. Here is the problem: I have new Kent Marine RO/DI HIS 60, and it has made only 140 gallons of water for 10 days till now. I have disconnect the unit from the water supply for a 1-2 days and after that, when I connect it again I have noticed that water has some smell, I check for nitrate, phosphate and ammonia and there is none. I have used some of this water in my knew tank and now I'm a little afraid of what might happen. <Because some water stays in the filter, it is possible for the water to become stale and if prevailing conditions are right [heat, light, etc.] you can even begin to grow things in the filters. This is probably what happened in your case. I would first try putting some of this water into a bucket or garbage can and aerate it vigorously... see if the smell goes away. If that doesn't seem to help, I would try running 10 to 20 gallons to waste and see if the smell goes away. If not, you may need to disassemble the three cartridge filters, bleach them and replace the cartridges.> I appreciate your help in advanced <If you plan to let this unit sit for any time, you should take it apart.> Regards <Cheers, J -- >

- RO/DI Water Smell? Follow-up - Uhhh... that is a quick reply. Thank you. After aerating heavily I can hard noticed that smell. What are you suggesting to me, can I use that water or not? <I think so, sure.> The unit now creates a water with no smell, but the first block cartridge is, let me say black, not dirty. <Replace it.> Is  possible that I must change it after 130 gallons of make up water. <Perhaps your source water is just really bad, so yes... it is possible that after 130 gallons that filter must be replaced.> Thanks again <Cheers, J -- >

"Water softener supply for a reef? Hello Mr. Fenner, <Steven Pro here today.> First I want to thank you for you taking the time to help all of the people you have. My self included! I have enjoyed WetWebMedia and found it to be totally reliable and very informative. <I am glad you have found the website useful.> This will be my first question to you as I have found just about all the questions I ever wanted to ask in WWM search engine. <I am particularly glad to hear of individuals using the search engine and FAQ files.> Question? While researching a different topic I stumbled across this article on FFE http://support.software911.com/ffexpress/faqdetail.asp? fid=2691. It seems to suggest that using a water softener on a reef tank could be problematic. Specifically it suggests that " I would not use water from a softener as it has been shown to cause problems with the fish's sodium balance". <Yes. Water softeners work similar to deionization units except when a DI unit absorbs a contaminant ion it releases H+ or OH- ion, leaving nothing but plain water behind. A softener releases Na+ and Cl- ions, leaving salt.> I live in Alaska and our water comes from a well, the well water has no problems other than a high iron content. The iron content is so high that I fear if I utilized the Kent Marine Maxima High-S RO unit before the softener that the pre filter and membrane would plug up in a matter of weeks. <Agreed, place the RO unit after the softener. The RO will remove the salts the softener imparts.> I understand that metals are harmful to a reef tank but iron is not that much of a concern? <There is a great deal of controversy on this matter right now. If you care to read about it, check out ReefCentral for competing views by Dr. Ron Shimek and Randy Holmes-Farley. I side with the chemists on this one and agree iron, in moderation, could be beneficial.> In your opinion, would you connect the RO unit before the water softener or after it? <After> FFE is the only place that I have seen mention that a water softener may be harmful to a reef tank and I can't find any contact information on Kent Marine. Should I be concerned with my current set up (makeup water drawn after a water softener and then run through a RO unit)? <No. Many large public aquarium setups are designed just like this.> My reef tank set up in detail can be seen here. http://www.reefaquariumguide.com/forums/showthread.php?s=&threadid=16836 <Your tank looks pretty good.> Thanks a lot, K.P. <You are welcome. -Steven Pro>" <Is merely a difference in opinion. In my thinking, if the RO/DI filter can remove the iron and other stuff, why add water softening salts only to remove them in the next filtration step by putting the RO/DI after the water softener. Likewise, the softening salts will shorten the life of your RO membrane perhaps sooner than normal. It's your call.> Thank you for your help J, K.P. <Cheers, J -- >

Evaporation Chemistry Hello, A quick first question or two from a long time reader. <Welcome back> If water lost to evaporation is mostly pure water then why do I need to buffer the DI water I use to replace the lost water? Don't the buffers stay in the tank when water evaporates? <Mmm, they get "used up"... very basically (bad pun), the overall reactions in closed systems are reductive (as in Redox)... they tend toward making the water more acidic... in effect exhausting the alkaline reserve> Second, how do I determine how much buffer to put in the DI make up water? I'm using Seachem Marine Buffer per a recommendation in one of the FAQs. <Best way is to measure your water (new) and try adding your buffering product/s with testing... per your particular livestock, desires for GH, dKH...> Thanks for providing such a terrific service to all new folks. Regards, Jim C <Thank you for your participation. Bob Fenner>

- Lifespan of Deionization Cartridges - I'm considering purchasing a Kent Maxxima system. I can find lots of info on how frequently to change the various filters, except for the deionization resin filter. I can't find any info on how frequently these need to be changed. Do you know? <The 'amount' of time is a range, depending on the quality of the source water. Most DI cartridges change color as the resin in them is used up. That's the best way to know when to swap it out. Cheers, J -- >

Water Softener 1/4/04 Hi guys, Hope you had a great new year <Hi Chris.  Adam here.  Same to you!> I live outside of the city and am on town water...all water that comes into the house is filtered through a water softener What should I be doing if anything to compensate for this when completing the water changes on my 110 salt FO system What I have been doing in the past, is turning off the water softener and letting the tap run for a while in an effort to get the softened water out of the system... Should I continue this practice in effect working to get the hardest water possible or should I just allow the softened water to enter the tank... Let me know <Water softeners work on ion exchange.  The ions in your city water that are responsible for the hardness (Ca++, Mg++, CO3-) and for scale production are exchanged in the softener for Na+ and Cl-. Over a long period of time, this could cause a slight imbalance in your tank water (more from top-off than water changes).  Regular partial water changes should help minimize this effect.  Adding an R/O unit to filter the already softened water is the ideal solution.  It will remove most of the NaCl, and the softened water is very gentle on RO membranes. If an RO unit is not an option, I would probably use unsoftened tap water filtered through a carbon block/sediment filter.  If you choose this option, please do get a water analysis from your water company to be sure that Phosphate and metal concentrations are acceptable.> thx Chris <Our pleasure!  Adam>

- 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 -- >

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>

Treating Source Water Hey, just a quick question regarding water purification. <Hey! Scott F. with you today!> I use an RO unit and then attach the "Tap Water Filter" (which is basically a DI unit) to filter out what the RO has missed. My question is, am I wasting my money and effort by using both an RO and DI unit? <I certainly don't think that using RO/DI is a waste, by any means. It may be a bit tedious using two separate units to accomplish this (you can purchase combination RO/DI units that integrate the two into one convenient package> Is this really necessary in reef husbandry? Will I notice any difference whatsoever in the health of my inverts or fish, or increased algae if I stop using the DI unit and just stick with the RO only. Thanks for your input. Angelo <Good question. I'd have to say that it is critical for the long-term maintenance of reef invertebrates and coral. Using purified source water and a good salt mix allows the hobbyist to provide his or her animals with a consistent, compositionally stable environment. Additionally, purified water reduces many potential nutrients, such as nitrates, phosphates, and silicates, that are known contributors to nuisance algae in aquariums. When all is said and done, you probably will notice a difference if you skip the DI step in your water purification process. The "difference" will probably manifest itself in the form of nuisance algae and potentially unstable water quality. You can read a lot more about RO/DI and it's role in captive reef water preparation on the wetwebmedia.com site. Hope this points you in the right direction! Regards, Scott F>

Learning the aquarist lingo - 2/13/03 I have spent a lot of time reading and researching the valuable info. on your website, and I like others-appreciate having a site like this available.   <thanks kindly> My problem is, there are so many abbreviations (or acronyms) used in the FAQ's, that I can't understand the information furnished. <Understood... but do use any search engine tool if necessary to plug in an abbreviation to get many hits with a likely translation in one of them. In time, all will be learned at any rate. No worries> For example,  in one response to a question, it recommended RO/DI water.   <RO = Reverse Osmosis, and DI = De-Ionized> I have no idea what that means, and it complicates my learning.  It would be really cool if you had a little spot on your site that spelled out a lot of the more commonly used abbreviations for those of us who are researching/learning. <A good point. I believe there is actually a page/thread like this on our WetWebFotos forum. Have seen it on many such message boards. I agree it is a good idea, but truthfully, it is a struggle most days just to keep up with the e-mail here. Still... we'll post this query like all on our dailies page with the hope that some daily reader has interest and time to pen a handy crib sheet. We'll be grateful for it and duly post it with credits in the archives> Please understand, I am not intending this as a complaint, you have a great site.   <No worries at all... understood... you make a very good point> I just want to learn more, and actually understand what it is I am reading. Thanks, Kim <Best regards, Anthony>

RO / DI water Hi guys, <Hi Brian> >Wow, I am amazed at how much there is to this hobby, I find it very interesting, just when I think I have read enough to determine an answer to my problem, there shows up a whole other set of questions. <Join the club, Dude! You should have seen MY questions today! It gets better and better!> I have a new reef setup, 2 ½ months old and been using purified tap water (well water) for top-off and water changes. <How is it purified? A Tap Water Filter (DI?) or ?> The brown diatom algae is very discouraging and looks awful. <Oh yes, esp. at about 2 1/2 mo.s! Even with great water it can happen in new set-ups.> I have added various snails, a brittle star, a goby, extra powerheads (helped the most) and still no luck. From what I have read it is probably due to nutrients in my water. <Most assuredly so!> I have a Remora skimmer driven by a Eheim 1250 pump, so I think that is fine, I do get a lot of darkish/greenish skimmate. (55gal tank, 65lb LR, 50lbs fine sand).  I was just about to purchase a RO/DI system until I read about just DI as well as Kati & Ani (hard to find lots of info and products for this).  I already have a sediment filter on my main pipe coming into the house, it would also be very easy to add a carbon filter. <Ah, more for chlorine, taste, smell, etc. for drinking.> Do I really need a RO system?  I see that Bob only suggests RO, but Steven and others only use DI or RO/DI.  I am not sure what to do, from what I just recently read, I believe my problem is from silicates and only need DI not a whole RO/DI system.  What is the difference? Why use of RO only, if it doesn't rid of silicates? Confused again.  Thanks for any advice you can give, I need a clean tank!  Brian <No worries, test your water for these contaminants, like silicates, phosphates, nitrates, etc. then match your pre-filtration treatment to your water. RO with the right membrane removes up to 99% or so silicates, but DI removes the remaining (assuming you are using a silicate removing resin). So, for most situations, a simple RO works fine. Some of the guys don't like RO because of the water used to produce pure water (a ratio of about 3 to 1 waste to product) where DI units including the Kati/Ani systems have no waste water but require recharging of the resin media when exhausted, as do DI cartridges.  DI cartridges last quite a while when used behind an RO membrane to remove the majority of contaminants. RO is very slow, depending on the size unit, where Kati/Ani will be much faster. All of these things plus expense then come into your decision.  Hope this sets you straight!  Craig>  

- RO/DI - Hi guys, <Hello, JasonC here...> I am amazed at how much there is to this hobby, I find it very interesting, just when I think I have read enough to determine an answer to my problem, there shows up a whole other set of questions. <I find that life is this way.> I have a new reef setup, 2 ½ months old and been using purified tap water (well water) for top-off and water changes. The brown diatom algae is very discouraging and looks awful.  I have added various snails, a brittle star, a goby, extra powerheads (helped the most) and still no luck.  From what I have read it is probably due to nutrients in my water.  I have a Remora skimmer driven by a Eheim 1250 pump, so I think that is fine, I do get a lot of greenish skimmate. (55gal tank, 65lb LR, 50lbs fine sand).  I was just about to purchase a RO/DI system until'¦ I read about just DI as well as Kati & Ani (hard to find lots of info and products for this). <DI[onization] is the same as Cation and Anion removal.> I already have a sediment filter on my main pipe coming into the house, it would also be very easy to add a carbon filter.  Do I really need a RO system? <You may... you might consider having your water tested to be certain.> I see that Bob only suggests RO, but Steven and others only use DI or RO/DI. <RO gets perhaps the largest portion of... shall we say, 'bad stuff'. Personally, I own an RO/DI.> I am not sure what to do, from what I just recently read, I believe my problem is from silicates/phosphates and only need DI not a whole RO/DI system. What is the difference? <In my opinion, the DI filter at the end of the RO/DI chain just get's the stragglers... RO filtration is more than adequate.> Why waste all that water and use RO only if it doesn't rid all of silicates? <The waste water issue is a non - if you are concerned, you can save the stuff and water you garden with it or whatever you deem necessary, but if you drive your car anywhere, those pollutants do much more damage than the water you would waste creating RO water. Most RO's do get rid of silicates... it's just marketing mumbo jumbo.> I would like to just buy 3 clear filter housings, link them together and run 1 carbon with 2 mixed bed filters (same as Kent's Deion 200 but much cheaper) is this a good idea? <Sure... it really all RO/DI filters are.> Confused again'¦ thanks for any advice you can give, I need a clean tank! -Brian <Cheers, J -- >

- 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 -- >

Water softener/need to change address for new book 2/27/03 Hey everyone well the day is approaching and I'm going to get to meet Steven Pro as I'm having him move my tank hoping to learn what a few things are as since they've arrived I haven't had  the time to search them out.  Anyway the new house we are moving to has a water softener in it.   <likely avoid this... > At the present it is not being used but is capable of being used can this water be used for a tank or should we just continue to by pass it?   <if it uses softeners salts or a single exchange resin, do avoid. If it is R/O then it may be fine. It will still need to be aerated and buffered before every use. Do get an evaluation of your tap water (free) from the local water municipality first. Do show to Steven too> Second question I have ordered and prepaid for your book due out soon how do I get in contact with your shippers to change my address?   <no worries... we are doing the ship out of the signed copies. E-mail here to my attention or send directly to me at readingtrees@yahoo.com. I will make the change. We will likely be shipping the text in April. Bob and I added content to bring the volume to 384pp from 300pp (no price change)> Thanks in advance for your help. Colleen <kind regards, Anthony>

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>

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>

Rechargeable De-Ionizers I just purchased a Kent Deion 200R, to replace the tap water filter that I have been using.  I bought this unit because they state that the media can be regenerated.  However, they don't tell how!  You have to use Muriatic acid, and lye!  Sounds dangerous to me. <Depends on your abilities and of course, desire to do so. You sound like an RO/DI candidate to me.> So, my question is, should I just send the unit back, or do you know of a business (Culligan?) that would regenerate this stuff for me. <You might check SpectraPure or even Kent. There are folks on the WetWebForums that have done this, perhaps check there.> Right now I feel like I have just paid 200 dollars for a large version of the tap water filter that I have been using. <More or less that's what you did. It sounds like you should return the unit before you use it and research a good RO unit for your water conditions, perhaps with a DI unit following the RO to remove any additional elements (silicates, etc.).> I probably could do the process of regenerating the media myself, but what do I do with the waste? <Call your county land fill and see if they have a facility for Muriatic acid, lye, etc.> I don't think that I want to put acid into my septic, and I don't think that I want to dump it down the curb, either. <Thank you for being a good citizen! The landfill or county/city will have a facility for this waste.> Thanks again for a great web site, I have used huge amounts of information from your FAQ's. Mike <Thanks Mike, hope this helps!  Craig>

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. 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>

Kent RO/DI Hey crew! I hope all is well with everyone. Do you guys know if there is a way to convert a Kent Marine 24 gpd RO/DI unit to a straight DI unit? I am tired of wasting water. Rock <I have never done it, but having a DI unit, I doubt it would be cost effective. Even if you could DIY the prefilters into additional separate resin DI units, they are small and would need constant recharging. -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>

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>

From Tapwater to DI Hi Rob, <Steven Pro this morning.> Just a quick question, if you don't mind. I've recently switch from tap water to DI water, to cut down Phosphate and Silicates. Seems to work OK, the brown algae has reduced noticeable, green algae still there though. Anyway, of greater concern is a drop in PH from about 8.5 to 7.5 (assuming my test kit is accurate!). Could using DI water cause the drop? <Yes. Any purified water has to be aerated and buffered before use.> What can I do to stabilize it at 8.5? <Aerate and heat the DI water for 24 hours. Then add your salt mix and test pH and alkalinity. Then add buffering compounds to adjust to the proper levels.> I probably have to get a KH test kit anyway to verify the tank's KH, but could KH have an effect on PH? <Yes, they are inter-related.> Calcium seems to be OK, about 380 - 400. Oh, just thought of one other thing, at about the same time I started using DI water, I switched brands of salt from Coralife to Instant Ocean. Any effect? <Yes, probably for the better.> Regards, Anthony <You are welcome. -Steven Pro>

From Tapwater to DI Follow-up Thanks, Steve. You just confirmed my suspicion. By the way, what do you used to buffer to water? <Any of the commercial preparations for marine tanks; Aquarium Systems Seabuffer, Seachem Reef Builder & Marine Buffer, etc.> Regards, Anthony <You are welcome. -Steven Pro>

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

Water softener supply for a reef? Hello Mr. Fenner, <Steven Pro here today.> First I want to thank you for you taking the time to help out all of the people you have. My self included! I have enjoyed WetWebMedia and found it to be totally reliable and very informative. <I am glad you have found the website useful.> This will be my first question to you as I have found just about all the questions I ever wanted to ask in WWM search engine. <I am particularly glad to hear of individuals using the search engine and FAQ files.> Question? While researching a different topic I stumbled across this article on FFE http://support.software911.com/ffexpress/faqdetail.asp? fid=2691. It seems to suggest that using a water softener on a reef tank could be problematic. Specifically it suggests that " I would not use water from a softener as it has been shown to cause problems with the fish's sodium balance". <Yes. Water softeners work similar to deionization units except when a DI unit absorbs a contaminant ion it releases H+ or OH- ion, leaving nothing but plain water behind. A softener releases Na+ and Cl- ions, leaving salt.> I live in Alaska and our water comes from a well, the well water has no problems other than a high iron content. The iron content is so high that I fear if I utilized the Kent Marine Maxima High-S RO unit before the softener that the pre filter and membrane would plug up in a matter of weeks. <Agreed, place the RO unit after the softener. The RO will remove the salts the softener imparts.> I understand that metals are harmful to a reef tank but iron is not that much of a concern? <There is a great deal of controversy on this matter right now. If you care to read about it, check out ReefCentral for competing views by Dr. Ron Shimek and Randy Holmes-Farley. I side with the chemists on this one and agree iron, in moderation, could be beneficial.> In your opinion, would you connect the RO unit before the water softener or after it? <After> FFE is the only place that I have seen mention that a water softener may be harmful to a reef tank and I can't find any contact information on Kent Marine. Should I be concerned with my current set up (makeup water drawn after a water softener and then run through a RO unit)? <No. Many large public aquarium setups are designed just like this.> My reef tank set up in detail can be seen here. http://www.reefaquariumguide.com/forums/showthread.php?s=&threadid=16836 <Your tank looks pretty good.> Thanks a lot, K.P. <You are welcome. -Steven Pro>

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>

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...> 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>

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

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 allot 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>

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