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FAQs on Tap water Filtration: Reverse Osmosis, Deionized, Distilled Water... 7

Related FAQs: RO/DI & Distilled Water 1, RO/DI & Distilled Water 2, RO/DI & Distilled Water 3, RO/DI & Distilled Water 4, RO/DI & Distilled Water 5, RO/DI & Distilled Water 6, 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 ChangesWater 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

Often, invertebrates are the first to show signs of "bad water" stress.

R/O for 10 gallon?      12/18/16
I was thinking of getting some blue tetras for a 29 gallon as a single species as they are very aggressive and nippy. These fish are hard to find and expensive per fish if you find them, so I was thinking of breeding them. The thing is the only hope for this is an R/O machine and a membrane to filter the water. This sounds pricey, but maybe cheaper over the long run as a way to breed tetras instead of always buying them. The other option is to buy distilled water if the fish stores have it.
<Mmm; expensive... and labor-some>
Do people do R/O in 10 gallon systems for breeding tetras or is it foolish to think such a thing is realistic? Thank you
<I/we use RO for most potable and cooking uses... have a device that makes 3-5 gallons per day... Not expensive to buy, operate in any period of time.
Inexpensive RO units can be had at Home Depot, Lowe's, Amazon.com.... Don't need one designated for aquarium use, nor deionization... just Reverse Osmosis... and to add some mineral back; as gone over on WWM (commercial
product or salt mix usually). Bob Fenner>

Purified Drinking Water OK to use? 1/7/2016
Hello, I'm currently in the market for an RO/DI system for my mini reef tank so I've been getting distilled water from Wal-Mart to hold me over until I can figure out which system
<Am in total agreement w/ this approach; investment. IF your water is questionable for aquarium use, it is likely so for your potable uses. An RO device is the best available, most appropriate means of rendering such water safe, useful>
I want to get. Last couple times I purchased Wal-Mart's distilled water it had zero TDS. Now today when I went to get some they were out of the regular distilled that I usually get so instead I purchased the green labeled jugs that are labeled as ''Purified Drinking Water.'' On the label: Source: Natural Spring at Hickory Spring SC. Processed by Reverse Osmosis and/or Steam Distillation, Micron Filtration & Ozonation. I thought ''great'', this should be just as good if not better than the water I usually get but when I got home and tested for TDS it showed 100ppm.
<Yes; "real" human drinking water should have solids... minerals and more... for taste as well as function>
I figured since it's labeled as drinking water maybe minerals had been added for taste but it doesn't say anything about added minerals on the jug so now I'm not sure I want to use it in my tank.
<Likely it is fine. Our S. Cal. water often has more than 800 ppm TDS... and I used it for decades>
I was debating on running it through some Poly Filter for a few days to see if the Poly Filter would show (via color change) if anything harmful was in the water.
And also thought about testing it for calcium, alkalinity, silicates & magnesium to see if any or all of these are the reason for the high TDS readings. But thought I'd ask here first just in case you know off the top of your head if this water is safe to use as is. So what do you think, is it likely just minerals added for flavor and nothing to worry about?
Thanks, Greg
<Likely nothing to worry about. Many salt mixes offered on the market have more than this level/concentration of contaminant components. Far better to put your emphasis on other aspects; enjoying your aquarium experience.
Bob Fenner>

well water /Carole      10/12/15
<Hi there!>
I have a 43.5 g. saltwater tank with 26.5 refugium. The display tank has 4x39W 36” fluorescent tubes on for 6 hr/day, and a MagDrive 5 and MagDrive 7 on 24/7 with an Aqua C EV-120, housing @ 50 lb live rock, 2 false *percula* clownfish, 1 yellowtail damsel, 1 Coral Beauty angelfish, all quite healthy and long-lived.
<Is this a fish only tank or do you have some coral as well? What kind of macro algae are you growing in your refugium and, for my final question, when you say "healthy and long-lived", how long are you talking?>
My problem is continuing cyanobacteria. I am on untreated potable well water and it is not practical to consider RO water <any particular reason why not? A good RO/DI unit can be purchased for less than $200 these days and they do a very good job of removing dissolved minerals/metals/etc... from the water and don't require hard plumbing and are considered a necessary part of equipment by many people. Also, are you adding a buffer to your well water/check the pH on your water? How frequently do you do water changes?>.
I have tried many ways over the years of at least reducing it, including vodka treatment
<Your well water is most likely your culprit and vodka dosing isn't going to do anything to help. Your well water may have something that the cyanobacteria love, not necessarily nitrates/phosphates. Water parameters from your tank would be a huge help here - (pH, ammonia, nitrites, nitrates, phos, calc, alk, etc..) as well as pH from your well water> .
Within a day it starts showing again, so I have just been putting up with it. My freshwater tank shows some green algae, but no Cyano, and to much less degree <whatever is in your well water is feeding the Cyano in the saltwater tank much more readily than in the freshwater>. My question is: would treating the prep water for water changes with bleach help? <absolutely do not treat with bleach> If so, how much for how long and how much dechlorination is suitable?
<Your problems with the water will not be helped with bleach. Bleach will kill bacteria, fungi, viruses, etc.. but not do a thing about what is dissolved in your water that is causing this issue. You would be better off with a good RO/DI system and, barring that, a UV sterilizer which will help reduce the Cyano as well>
Thanks for your help -
<No problem! ~ Carole>
Gai Burnett
well water /RMF     10/12/15

I have a 43.5 g. saltwater tank with 26.5 refugium. The display tank has 4x39W 36” fluorescent tubes on for 6 hr/day, and a MagDrive 5 and MagDrive 7 on 24/7 with an Aqua C EV-120, housing @ 50 lb live rock, 2 false percale clownfish, 1 yellowtail damsel, 1 Coral Beauty angelfish, all quite healthy and long-lived.
My problem is continuing cyanobacteria. I am on untreated potable well water and it is not practical to consider RO water.
<Mmm; impractical? Such units are VERY inexpensive to procure and run.... AND if your potable has issues... you should move forward for your drinking and cooking needs in addition>
I have tried many ways over the years of at least reducing it, including vodka treatment. Within a day it starts showing again, so I have just been putting up with it. My freshwater tank shows some green algae, but no Cyano, and to much less degree.
My question is: would treating the prep water for water changes with bleach help?
<Mmm; not likely... can only tell by analysis of the water, or actual use/bio-assay of the chlorine bleach treated water. This is NOT the route I would go>
If so, how much for how long and how much dechlorination is suitable?
<A day, then removal w/ Thiosulfite.... again.... there are other approaches to BGA control. READ here:
AND the linked files above, AND
on WWM re RO, AND get a unit.... WITH an auxiliary pump if your pressure is low>
Thanks for your help -
Gai Burnett
<Welcome. Bob Fenner>

well water /Carole      10/12/15
<Hi there!>
I have a 43.5 g. saltwater tank with 26.5 refugium. The display tank has 4x39W 36” fluorescent tubes on for 6 hr/day, and a MagDrive 5 and MagDrive 7 on 24/7 with an Aqua C EV-120, housing @ 50 lb live rock, 2 false *percula* clownfish, 1 yellowtail damsel, 1 Coral Beauty angelfish, all quite healthy and long-lived.
<Is this a fish only tank or do you have some coral as well? What kind of macro algae are you growing in your refugium and, for my final question, when you say "healthy and long-lived", how long are you talking?>
My problem is continuing cyanobacteria. I am on untreated potable well water and it is not practical to consider RO water <any particular reason why not? A good RO/DI unit can be purchased for less than $200 these days and they do a very good job of removing dissolved minerals/metals/etc... from the water and don't require hard plumbing and are considered a necessary part of equipment by many people. Also, are you adding a buffer to your well water/check the pH on your water? How frequently do you do water changes?>.
I have tried many ways over the years of at least reducing it, including vodka treatment
<Your well water is most likely your culprit and vodka dosing isn't going to do anything to help. Your well water may have something that the cyanobacteria love, not necessarily nitrates/phosphates. Water parameters from your tank would be a huge help here - (pH, ammonia, nitrites, nitrates, phos, calc, alk, etc..) as well as pH from your well water> .
Within a day it starts showing again, so I have just been putting up with it. My freshwater tank shows some green algae, but no Cyano, and to much less degree <whatever is in your well water is feeding the Cyano in the saltwater tank much more readily than in the freshwater>. My question is: would treating the prep water for water changes with bleach help? <absolutely do not treat with bleach> If so, how much for how long and how much dechlorination is suitable?
<Your problems with the water will not be helped with bleach. Bleach will kill bacteria, fungi, viruses, etc.. but not do a thing about what is dissolved in your water that is causing this issue. You would be better off with a good RO/DI system and, barring that, a UV sterilizer which will help reduce the Cyano as well>
Thanks for your help -
<No problem! ~ Carole>
Gai Burnett
well water /RMF     10/12/15

I have a 43.5 g. saltwater tank with 26.5 refugium. The display tank has 4x39W 36” fluorescent tubes on for 6 hr/day, and a MagDrive 5 and MagDrive 7 on 24/7 with an Aqua C EV-120, housing @ 50 lb live rock, 2 false percale clownfish, 1 yellowtail damsel, 1 Coral Beauty angelfish, all quite healthy and long-lived.
My problem is continuing cyanobacteria. I am on untreated potable well water and it is not practical to consider RO water.
<Mmm; impractical? Such units are VERY inexpensive to procure and run.... AND if your potable has issues... you should move forward for your drinking and cooking needs in addition>
I have tried many ways over the years of at least reducing it, including vodka treatment. Within a day it starts showing again, so I have just been putting up with it. My freshwater tank shows some green algae, but no Cyano, and to much less degree.
My question is: would treating the prep water for water changes with bleach help?
<Mmm; not likely... can only tell by analysis of the water, or actual use/bio-assay of the chlorine bleach treated water. This is NOT the route I would go>
If so, how much for how long and how much dechlorination is suitable?
<A day, then removal w/ Thiosulfite.... again.... there are other approaches to BGA control. READ here:
AND the linked files above, AND
on WWM re RO, AND get a unit.... WITH an auxiliary pump if your pressure is low>
Thanks for your help -
Gai Burnett
<Welcome. Bob Fenner>

RO/DI pH question     1/4/13
Hey Bob,
<Morning Jay>
Quick question... Yesterday when preparing the dip water I used the pH probe from my main system to match the dip water with baking soda. The pH of the RO/DI was 9.8!
<?! Something wrong here>

 (My tap water is neutral at about 7.2).  When I started adding baking soda the pH dropped a little at a time until it reached 8.2. Is that supposed to happen?  I'm thinking maybe my RO system is in need of cartridge changing.
<Ah yes. Please search WWM re RO maintenance; or read your way through here: http://www.wetwebmedia.com/romntrep.htm
and the linked files... B>
Thanks again,

possible resin mistake, RO/DI use, SW      9/6/12
Hi guys,
First I will let you get your lashing out of the way, I tried something without thoroughly researching it first  :(
I do spot free window cleaning for my business and bought some resin from a window cleaning supply company in bulk (25lb bag).  I thought to myself..hmmm an extra bit of this for the output of my RO unit couldn't hurt.
<Well... there are many such "resins"... not that many that are of use here>
 It did, a lot of my corals now look unhappy and my tank has started blooming algae like there is no tomorrow.  The tank has been established for 7 years and has NOT had any changes/addition in over a year.  It only seemed to take about a month for it to get really bad, and after doing a 20% water change I noticed it got worse.  Then I started to assume it was possibly the resin.
Now I know if I would have asked first the answer would have been:  "I don't think I would take the chance" but since what's done is done, I am trying to see if it is coincidence in timing and there is another possible problem or could the DI be causing my algae blooms?
<It could indeed>
 Have you ever heard of a DI resin sold in bulk that maybe leaches phosphates or something else?
<Yes... though it's been a few decades, I taught H.S. level chemistry and physics, and have remained an active learner...>
  The water was showing 2ppm
<Of H/PO4? This IS a bunch>
 in the output, but could there have been something else in there that doesn't register in ppm?
<Oh yes... there are (expensive) tools like mass spectrometers that can tell more of what is in a sample...>
I have (obviously) removed the DI cartridges and did one 10% change last night,
<I'd change out 50% myself>
 but don't know how long it should take before I should notice a major difference.  I didn't want to do to much more of a water change since I just did 20% a few days ago.
<Up to you>
Any other advice besides more water changes? (and researching before you act)
<I'd look into what this ion-exchange resin (likely) actually is, contact the manufacturer re application, side effects>
Thank You,
<Welcome. Bob Fenner>

RODI Drinking Water Safety 7/20/11
Dear WWM,
I live in earthquake country, also know as Southern California. I am in the process of updating my emergency preparedness kit. I currently store RO/DI water for my reef tank in a large trashcan. I am curious to know if I could use that water for drinking water in case of an emergency.
<Yes it is.>
I have read conflicting reports on the safety of using RO/DI water for drinking water. I have read it's never safe, safe temporarily, and always safe. Are you aware of any research based articles on the safety of using RO/DI drinking water on a temporary basis?
<Am not right off hand, but am more than VERY sure that these exist. You have tried searching the Net? The companies that make these units could very likely point you to references>
If it's unsafe, are there any additives that make it safe?
<Though it lacks mineral content, these can be made up easily through vitamin et al. supplementation, foods. Bob Fenner>
Thank you,

Water filtration question, DI Fe ions, cartr. repl. meas.    2/20/11
Hi crew,
I've been running a constant drip system on my 240 gallon aquarium for some time. The water runs through 1 sediment filter, 2 carbon cartridges, and 2 De-ionization cartridges.
My filtration unit is located in the laundry room, plumbed off of the washing machine supply spigots. I've recently included warm water from the hot water supply.
<Does this hot water go through your DI system?>
It just so happened that my timing was perfect as my tank's heater failed soon after, and I had to rely on this warm water to maintain my tank's temperature until the new heater I ordered arrived.
I've recently read on one of the forums that I belong to a post regarding a strong concern with "iron" content from one's tap water, particularly water coming from a water heater.
<Mmm, unusual that this much iron derives from potable sources>
I began doing some research and read that De-ionization removes heavy metals including iron. Can you confirm this?
<It does>
I also read that some people measure the TDS to determine when it's time to change out the components in their filters. Is this a good practice? If not, can you suggest a better one?
<TDS, conductivity... are fine as measures>
I look forward to your direction.
Thank you,
<Welcome. Bob Fenner>
Re: Water filtration question part 2   2/20/11
Hi crew,
Yes the hot water (now warm after mixing with cold water from the other spigot) does run through the DI system.
Can the gas water heater be a source of iron?
<Highly unlikely; no>
Can you recommend a type/brand of TDS test (kit)
<See the Net re Merck, Hach... or the outfit that sold you the DI unit, repl. cartridges. B>
Thank you,

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

Thanks for responding and clarifying Neale and Bob. :)
<Glad to help.>
I can definitely agree on the cost issue for those that do not have their own home distiller. Paying 30 cents or more per gallon at a store is far from economical.
I currently have 2 distillers running in my home capable of producing 30 gallons per day. They only cost around $25 per month to run on average,
<<?! Incredibly cheap. Back in my H.S. teaching days we had one that ran on resistant heat... to boil the water into vapor... I can only imagine what it costs to run nowadays>>
so the cost is much better than going to a grocery store for RO or Distilled water. The bigger the distiller, the more economical they are to run as well usually. A 1 Gallon per day unit usually costs a bit more to run than a 10 gallon per day unit. I've seen some Distillers capable of producing 600+ gallons per day and they can do it for less than 3 cents per gallon.
<<Not in S. Cal.>>
 Granted the initial cost of the Distiller units is very steep, but over the long run they do usually pay for themselves.
<Fair enough.>
For using only Distilled, I haven't really noticed PH swings or anything after water changes. I usually change 10-20% twice per week in my tanks, depending on Nitrate levels. Really as soon as the distilled water mixes with the existing water in the aquarium, it's no longer distilled. Water comes out of my distiller at a PH of 6,
<<W/ aeration, time going by, should come up to near 7>>
 but I find my tanks are usually around 7.2 before and after water changes and I don't use any buffering chemicals. The existing water in the tank has a small mineral/salt content just from fish detritus decomposing, and that effectively is a buffer of sorts I guess.
<Possibly.><<Lo dudo>>
My water tests in the tanks usually show around 80-100 ppm dH/KH.
<Degrees dH and degrees KH aren't the same thing. And if your "distilled" water contains either 80-100 mg/l CaCO3 or CaO, then it's not distilled water. Ask yourself where the general hardness and carbonate hardness are coming from. Yes, 100 mg/l CaCO3 carbonate hardness will buffer water to a certain extent, and should ensure a pH around 7.5, plus or minus a bit, much like you're seeing. But pure distilled water obviously shouldn't have any CaCO3 at all.>
<<Agreed... something is amiss here. I don't think you're using a distillation apparatus, or something is faulty w/ the unit. Am dubious that resident material (substrate, rock, decor...) is supplying this much hardness>>
As long as the tank is cycled with fish in it, and you aren't doing 90% changes weekly, there shouldn't be any real swings.
<On the contrary. There are very good reasons why pH will drop if water has a low buffering capacity. Anything less than about 80 mg/l CaCO3 is low carbonate hardness, and such water can, will experience a downwards pH drop between water changes. Do read:
In my invertebrate tanks I do add 1/2 strength Kent Iodine and Liquid Calcium though. And I have a couple planted tanks that get some plant supplements added. As I mentioned previously, I like to add my own minerals to the water so I know exactly what is in there. :)
<With a freshwater aquarium you rarely need to be so fussy. In my case, my tap water comes out as liquid rock, with very high hardness and carbonate hardness thanks to the chalk aquifer. The pH is around 8. But a 50/50 mix with rainwater produces a very useful blend suitable for almost all community fish. I don't need to worry too much about the details because the carbonate hardness is still high enough to ensure pH doesn't move much either way. Easy peasey.>
I can't agree on the Tap Water quality part. I might have a bit of conspiracy theorist in me though. ;)
If you saw the sludge I clean out of the distiller's boiling chambers every couple months you might not want to ever touch straight tap water again either. ;)
<I'm sure your drinking water is medically, demonstrably safe. Sure, if you accumulate all the detritus over a few months that'll add up to a nice big lump. But if you did the same thing with the air you breathe it'd come out as a big lump of dust and debris as well. The fact is that your body evolved to handle water far worse than anything your water supplier sends down the pipes. Given that the water you get from the tap before you distill it is perfectly drinkable, you're really just wasting energy and water in the process.>
After distilling approximately 500 gallons, I can pull out a quart of scale and sludge. It's just nasty to think that people drink that stuff and the WHO says it's "Ok".
<It's not nasty; it's science. Let me ask you, do you drive? I can bet you that driving puts your life at far more risk than anything in your water supply. The thing with human beings is we tend to obsess about trivia while ignoring the big picture. We're amazingly good at this, and advertisers rely upon. If you were given nothing to drink but your potable tap water, I can guarantee you'd live a long and happy life. Indeed, by cutting out alcohol you might even be a bit healthier!>
On a related note, most US Embassies overseas as well as many of our military bases and federal buildings also run onsite distillers.
<For different reasons. Embassies and military bases need to ensure independence from local suppliers, partly for security and partly for healthcare. If you have a base in country X and someone goes and dumps poisons in the local water, then your soldiers are at risk. Much the same if there's a natural disaster or a cholera outbreak. Distilling water removes these risks, at least on paper.>
Those that don't run RO/DI filtration instead. If tap water isn't good enough for the government, I can't really trust them when they say it's good enough for the general population.
<I don't think this is an issue at all. Governments don't state that water is safe; doctors do. Governments merely enforce standards. You may argue about things like the taste of tap water, but I don't think anyone has said that American tap water is unsafe to drink. Lots of people will sell you hardware to "purify" your tap water, but it's all nonsense as far as the medical facts go. At best, you're spending money to change the flavour of the tap water. But you won't live an extra day longer because of it.>
I can agree that for the casual fish keeper with a single 10 or 20 gallon tank, it's probably ok to use tap water with a water conditioner. Once you start getting over 100 gallons of water though, that water conditioner can start getting expensive if you are keeping up with regular water changes.
<Not at all. Simply buy concentrated pond water conditioner. Much cheaper! In fact I've done this for years and find it very economical. In any event, the energy and water costs involved with distilling water or using RO/DI are massive, and far outweigh the cost of tap water and dechlorinator.>
<<I don't use any conditioner/s at all... Merely change less percentage water, or store water for a week or so ahead of use>>
Also if you have any sort of a top off system running with tap water you can potentially be building up some harmful stuff in the tank water over the long run (i.e. Copper).
<No. Assuming you do water changes, anything added to the tank eventually gets flushed out. So the concentration of copper will remain more or less constant, depending on what the amount is in your tap water. There may be some slight uptake by calcareous rocks or whatever, but the impact is generally trivial. The idea copper builds up in the tank week over week is wrong. Each weekly water change will remove about the same amount of copper that was added the week before. Unless your tank is losing wild amounts of water through evaporation, you shouldn't really see any change in the chemical composition of the water in your tank.>
Anyway, thanks for the comments guys, I appreciate it.
<Happy to chat. Cheers, Neale.><<BobF>>
Re: More Re: Comments about Distilled Water? (RMF, you might want to comment on your comments here'¦)<<>>   10/6/10

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

Re: Water Purification System - 1/17/08 Thanks so much. <Very welcome.> Just to put it out there..........A friend of mine wrote me a warning to say that reverse osmosis purified water should not repose in copper tubing as it leads to toxic levels. He is generally well read so be warned and thanks for the tips. john Zunich <Yes, I have read about this, though have no first hand experience. The theory is the water has a great carrying capacity for CO2, making it more acidic and corrosive. Will pass this along. Thanks, Scott V.>

Re: Water Purification System - 1/17/08 To support this my take on this after reading his dissertation, is that the removal of minerals is the real cause and effect of the aforementioned phenomenon. All the best, john Zunich <Yes, thanks for the info John, Scott V.> RO Membrane Exposed to Hot Water! -- 01/12/08 Good day Crew. <<Greetings Andy>> I may have done something stupid today. <<Oh?>> I was filling up my water reserve. I mixed cold and hot water so that the water running through my RO/DI unit would be a little warmer (I connect using a spigot cap rather than a piercing valve). I normally don't do this but it is cold here today. <<Mmm, yes'¦an RO membrane will work more efficiently with warmer water than with colder water. But using hot water from the tap may not be the best approach as this heated water generally carries/pulls more contaminants (metals) from the metal water pipe which may shorten the life of the membrane (along with your sediment filter and carbon filter cartridges). One approach is to coil about 20ft of ¼' tubing (between the source and the filter unit) in a bucket of water and place an aquarium heater in the bucket to heat the water, which in turn will heat the water slowly feeding to the RO unit through the ¼' tubing in the bucket>> When I had filled my vessel, I switched on the flush valve to flush my RO membrane as I always do. <<A good practice>> When it had flushed, I shut off the cold water but forgot that I had turned on the hot water as well. <<Mmm'¦>> So, hot water flushed the RO membrane for about 5 minutes until I realized what was going on. I immediately shut off the hot and ran the cold until the water coming out of the waste water tube was cool. The water was never burning hot, but it was definitely hot. <<I see>> I remember reading somewhere that hot water will totally ruin a RO membrane. Is this so? <<Can damage the composite material, yes'¦but I think it would need to be 'very' hot>> My TDS meter shows 100ppm going in and 0 ppm coming out. Is this proof that I haven't ruined the membrane, or is there some other way of ensuring? <<With this reading, and if output does not seem overly diminished, I think the membrane will be fine. But truth is'¦time/further use should tell. But if you are overly concerned, then I would write the manufacturer of the membrane for their opinion>> Thanks. Andy <<Happy to assist. EricR>>

Disaster...no Clue. AP TWP, some sort of catastrophic cascade poisoning event Hello!   12/9/07 I have a major problem with my tank and have spent 3 weeks trying to sort it out. I have searched your site and just can't seem to find anything that relates to my situation. <Let's see...> My set up is a 90 gallon with a Pro Clear 150 series 2. <This wet-dry? http://www.amazon.com/dp/B00061UXXC?smid=AEL917WTFL8PV&tag=msnshop-pet-mp-20&linkCode=asn> The tank has been up and running for over a year now with no problems. Nitrates, Nitrites and Ammonia all at zero. PH runs about 8.2. I added some red Gracilaria to the Sump. (After the skimmer below bio ball before the return) I was running a light on opposite cycle from the main tank lights as well. A month after adding the Gracilaria I started to see copods <No such thing... Copepods> down there and when I did a water change they would sometimes go flying out into the tank. A few of them took up residence around some of my polyps and pulsing xenia. Life was good in the tank! I did water changed weekly of about 10 gallons. This went on for a year with no problems or losses. <Good> Rather than purchase water I decided to invest in a Tap Water Filter by Aquarium Pharmaceuticals. <Mmm, please see WWM... this product is unworthy... a toy if you will... Not cheap or really functional to produce clean water> I did some reading and this was supposed to be a great product. Recommended by Jack Watley and all. <Jack... Wattley... knows better than to have lent/sold his name here. I will say no more re> I mixed up my first 5 gallon batch and decided to test it first since I wanted to be sure the water was good before adding it to my tank. Testing pre-salt showed 0 nitrates, nitrites, ammonia and chlorine. I did note the PH was very low. Around a 5.0 but once I added the salt mix it came right up to the 8.0 level. I added the 5 gallons and then mixed the next 5 gallons. Testing again gave the same results. While I was working on the tank I decided that I would add a little of the bio active sand to the sump. I placed it down with the Gracilaria to try and keep the pods going strong. The next morning it looked like a war zone. Pulsing xenia was withered away and the mushroom leather corals were all shriveled up. I tested and found my nitrates 20 nitrites were at .5. <Yikes...> Panic set in so I went and did another 10 gallon water change. Again, testing the water before placing it in the tank. 24 Hours later my nitrates 20 nitrites were at 3.0 and all coral, blue leg, emerald green, peppermint and cleaner shrimp were dead. <Yes... poisoned> I again did another water change, this time I did 30 gallons. The nitrites came down to .5 and I decided to go and purchase some Prime since it seemed my tank was in a cycle. Odd thing is ammonia was 0 or .5 during this whole ordeal. <Not all microbes mal-affected evidently> Day 4 I tested and now the nitrates 20, nitrites were at 5.0 I lost a chromis ammonia was .05. I did another 30 gallon water change and got nitrites down to 1.0. I decided that perhaps too many water changes were causing a cycle. I had to go away for 3 days and the tank just sat. I turned off the lights as to try not to stress the remaining fish. Upon my return the nitrites were back up, but to 10.0 this time! Nitrates were 40 and believe it or not 2 false percs, yellow tail blue tang and lawnmower were still alive. Ok, so the tank is clear I thought maybe it's my test kit. I got a brand new kit and tested. Nitrates 40 Nitrites 10.0 and ammonia at .5. Two test kits same readings. So a week after using the new water filter and adding the sand I am in a mess. I did water changes of 10 gallons every day for a week. That kept the nitrites at about 3.0 all week. I then tried cycle to see if somehow it would help balance things out. Day 14 I added the cycle nitrites were 3.0 nitrates at 10. The next morning I was looking at Nitrates over 200 and nitrites over 10 ! All 4 fish were still alive. I tried both test kits same readings. <Yes... a cascade effect... the nitrogenous materials are/were derived from the rapidly decomposing biota...> I know it seems like I am just throwing stuff at the tank to make something stick but I tried water changes I am starting to think that it's the water I am using from that filter. <Likely this is/was the origin here> (Perhaps I am being stubborn and I could just go buy water again but after shelling out the money for the water filter and testing the water and it being fine I figured that can't be the cause) I DID test each batch before placing it into the tank and it was fine. <... for what you were measuring...> Perhaps my local water becomes unstable after going through that filter? <Mmm, not the source water, no... but possibly the TWP> I have replaced the filter now twice since it is only good for about a 100 gallons. My readings were good but since the package said "up to 150 gallons" I did not want to press my luck. <... Let me cut to the proverbial chase. I'd toss the TWP... and look into, buy a real water filter... either an RO or RO/DI device...> So at this point what would you suggest? More water changes? Just let it sit and run it's course? Light on ? off ? More prime? More Cycle? Take the sand out of the sump? Trash the water filter? <Yes to the second, and last, no to all others> It's been about 3 weeks now and the 4 fish are still alive but the Gracilaria lost it's color completely. I added a little more to the tank to see and it too lost it's color. LOST and in desperate need of some direction here. Thanks So Much I just know you can give me some help. Derek <Please, take your time... and read here: http://wetwebmedia.com/marine/setup/index.htm the sixth/blue tray on water... the sections, articles, FAQs files on treatment/filtering. Bob Fenner>

RO/DI water 11/30/07 Hello <hello Steve> I found many sections on aerating and buffering newly made RO/DI water for water changes and makeup water. My question is if I'm adding Kalkwasser to a gallon of water to drip into my system does this also need to be aerated and buffered first? If RO water has a low PH wouldn't the high PH Kalkwasser offset this? <Your question is a good one. pH is lower after coming out of a RO unit because many of the "minerals" that would buffer pH have been removed. Once the water flows from the RO to the DI unit it has ALL the minerals removed, leaving pure water. This water has 0 TDS and is a very "soluble solvent". This means it is eager to absorb any mineral content that it exposed to. Therefore, mixing it with Kalkwasser (Calcium Hydroxide) will immediately have a reaction. The pH will soar up to 9.0 and the hardness will soar to 8-12DKH. This is good for a Saltwater tank as it adds calcium and buffer to the tank. As far as making it goes, add your dry powder to your 1 gallon jug, then shake very well so that you dissolve as much as possible. Then let settle so that you go from cloudy water to clear water. The only thing you want to add to the tank is the clear water. Then just drip that in overnight each day or as necessary (depending on your rate of evaporation) Hope this helps-Rich.. aka. Mr. Firemouth) Thanks Steve

TDS and algae 11/24/07 Hi there. <Hello.> I just measured the TDS of my source water (run through my relatively new Coralife 3 stage RO unit) at 17 TDS. Could this in itself be the cause of an ongoing problem with GHA and Bryopsis?? <Probably not, a TDS of 17 out of an RO is not too bad.> Being that I have tried to remedy the problem in every other possible way (with the exception of using antibiotics), <Wouldn't help if it is algae.> I was banking on this being the explanation. Before I had a TDS meter to know for sure, and was actually expecting the reading to be a lot higher. FYI, my tank is 65G sumpless, mixed reef, Nitrates 0, Phosphates 0, PH 8.4, 5 small fish, Aqua C Remora, Aqua Clear HOB running carbon (changed monthly), MJ1200x2. Any thoughts on this would be appreciated. <You may want to test your makeup water directly for nitrate and phosphate after you have mixed the salt. Any mechanical filtration in the HOB should be cleaned at least once a week; detritus in it will raise your nitrate and feed your algae. Feed sparingly and make sure your water flow is keeping things mixed up (no settling). Please read through the website on substrates, they can also pose issues regarding nitrate and algae. Just keep testing and searching, you will find the source. Welcome, good luck, Scott V.>

Question about new TDS meter 10/29/07 Hi Crew, <Tom> I have a basic 3 stage RO unit running for 18 months now, with these components: 1 micron sediment filter 5 micron carbon filter 50GPD Dow Filmtec TFC membrane (from Premium Aquatics) <Okay> I've long thought that I might need to invest in a unit with a DI stage to get better water for our reef tank. To find out how effective this little RO unit is, I just installed a new HM Digital Dual TDS Monitor (http://www.tdsmeter.com/products/dm2.html). I have not tested for TDS prior to this. <All right> Based on reading many of the WWM FAQs on TDS and water filtration, the readings I'm getting are better than I was expecting. The incoming probe reads 50-52, the output probe reads exactly 0. As an experiment I switched the incoming probe to the output side of the RO, and it now reads 0 as well. So the TDS monitor appears to be working, right? <Oh yes> We live in Western Oregon and enjoy relatively clean tap water, but I'd like to ask your expert opinion on whether it's typical to get a TDS of 0, using only a basic 3 stage RO. <Mmm, yes... if the unit is "in good shape", the starting water not too solute laden...> And, would there be any point to adding a DI stage if the TDS is already at 0? <Not IMO> Thanks, Tom <Welcome. Bob Fenner, a huge fan of RO... have used for three plus decades... for all cooking, drinking... and some pet-fishing.>

Reverse Osmosis Filters for the home... and the reef tank. -- 08/02/07 Hi. <Hello Ghulam, Mich here.> Can I use a normal domestic RO/DI unit for my reef tank? <Yes. More here: http://www.wetwebmedia.com/ca/volume_2/cav2i4/RO_systems/reverse_osmosis.htm > Ghulam

Quick One... RO water  7/31/07 Is buying a reverse osmosis system for water changes worth it or is it the same as water conditioner? <Is well worth it and is not at all the same. Buy a $20 TDS meter at your local home improvement store and you will see the difference. RO water should have zero total dissolved solids, most water will have significantly more. You can read more here: http://www.wetwebmedia.com/water4maruse.htm http://www.wetwebmedia.com/ca/volume_2/cav2i4/RO_systems/reverse_osmosis.htm Mich>

H2O Purifiers 7/31/07 Good morning, <Good morning, Kim> I will be quick as I know you are inundated with emails! <Thank you.> I recently purchased a Kold-Steril unit to filter my tap water for use in my FOWLR tank. The reason is that I have been battling hair algae and came to realize that phosphate in my tap water is the culprit. I installed the Kold-Steril unit, including their alumina media. I ran 50+ gallons through at 1-2 gpm per instructions to "flush" the system. After all this, I am still testing phosphate in the water. Questions: 1. Do I need to flush more water, or is this typical and will not change? <I would increase the contact time, say 1/2 gallon per minute, and then see if you are still reading phosphates.> 2. I am willing to add a DI unit after the Kold-Steril if this will help, but I'm not sure if it will do anything for phosphate. I'm just fearful of throwing good money after bad. Your advice here is much appreciated. <Try increasing contact time first.> 3. Is all DI resin created equal? - ie - can you get any more life out of the resin by purchasing a better quality resin? If you recommend adding DI, is there a brand you prefer? <I believe the resin units available to aquarists are pretty much the same, no preference. Do read FAQ's re Kold-Steril from other queriers and our responses. Go here http://www.wetwebmedia.com/koldsterilfaqs.htm Regards, <You're welcome. James (Salty Dog)> Kim PS......water is very expensive where I am, hence the avoidance of RO. <Mmm, where do you live?> 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

Water Filtration, Top offs, and Storing Saltwater 4/26/07 Jason here from Manila.  Hope you're doing well too :) <Greetings, Jason! GrahamT with you this fine, rainy morning in Maine, USA.> My water company delivers filtered water to my doorstep.   <Cool!> However, I am not sure about the quality of the water, and if they use copper for its distillation process.   <Can be tested for...> I also believe it is RO water.   <Is likely. Commonly used form of purification.> What kind of tests should I do on the water to determine if it is safe for my reef tank? <I would test for ammonia, nitrite, nitrate, calcium, phosphate and copper. If you are curious, you could add total dissolved solids (which should be at or near zero if it IS RO) and iron. These can be useful kits for any aquarist, but they *ARE* seldom-used and the kits do expire so... it's your call.> If I'm going to do my own filtration on my tap water, is it ok to just do RO, and not DI? <That depends on what you want to accomplish. For most cases, RO will suffice. I would venture that if your tap water is safe to drink, then you can buy a simple RO (read: two or three-stage) with acceptable results. However, the more you invest initially in your RO unit, the more it pays of in the end. Multiple stages of pre-filtration before the RO-membrane extend the life of the membrane and soften the blow to your wallet. If you do go with a many-stage unit, then the addition of DI is warranted, IMO. The level of stuff that would make it to the DI in that case would be minimal, and thus the DI cartridge would last quite a while. All these different choices will be prompted by the tests you carry out on your tapwater.> I plan to make a DIY top off system.  Does the water need to be constantly aerated with an airstone & pump to keep oxygenated? <Not *constantly*, but if you plan to keep it for long periods (like weeks) in the same container, you need to provide movement and aeration to avoid stagnant water.> As part of my routine of making saltwater and storing, can I keep it in containers where it is not circulated and not air pumped for weeks at a time, and then when I need to use it, I can airstone it and circulate it for x hours - would this be ok?   <If you are driven to store the water for a long time, then I would store just the purified fresh water, since there is less chance of it growing bacteria and algae whilst sitting. Then you can mix it up in due time for its use.> If so, how long should I aerate/circulate it prior to use?  Is there anything I should watch out for here? <Aerate and circulate for at least two days after you mix the salt, and then feel safe using it.> Doing water changes - when I water change, I aerate and use a water pump for circulation prior to use. However, this makes the water much warmer than my tank.  Is it ok to let it sit without aeration/circulation for 2 hours (while it cools down) prior to use? <The aeration alone shouldn't heat the water, but in either case, letting it sit for a matter of a couple hours is detrimental in any way. By all means, let the water cool. Good luck! -GrahamT>

DI and Prefilter Cartridges...Need For RO? - 04/19/07 Hello again, <<Hi Brian>> I am interested in two canisters for water purification at my local home improvement store.  The first one cost about 20 dollars and is a standard whole house canister.  This one had input and output holes for tubes or pipes about 7/8-inch.  The second is about 35 dollars and is for a sink.  This one has input and output holes for tubes that are 1/3 outer dimension, I'm guessing the tubes are 1/4 inch inner dimension.  What are the size of the tubes that are standard for Deion canisters used in the fish hobby? <<Quarter-inch tubing is pretty much standard (like the tubing used with hobby RO units).  You needn't worry much about the input/output sizes on the canisters though as these can be bushed up/down as needed with threaded adapters available at those very same home improvement stores>> I was hoping to get separate refillable cartridges for cation and anion deionization. <<Sounds reasonable...and keeping these resins separate will greatly facilitate cleaning/recharging if you so choose>> Would this work for use with either canister I described at my local home improvement store? <<It will...though if you are buying your resin in bulk (I recommend a peek at resindepot.com); you will need to acquire some "refillable" resin cartridges for use in the canisters>> I was wondering if the water flow speed would be too fast for either canister I described? <<What water flow speed?>> If the 7/8-inch canister would be too fast, but the 1/3 outer 1/4 inner dimension canister would work, could I still use the 7/8 canister for carbon and Poly-Filter or would it be too fast still? <<Though flow is affected by tubing diameter, it is not a concern here.  The "flow speed" will likely be dictated by your input water pressure and volume.  But regardless, you will still want to install a valve (pre- or post-filter unit...won't matter) to adjust flow as needed by checking the TDS of the filter effluent; with new cartridges installed, to make sure the flow is not faster than the resins can handle.  The resin manufacturer may even provide you with an "optimum" flow rate which you can then measure/adjust using the valve>> I just wonder because I would rather use the cheaper 7/8 canister 20 dollars v. 35 dollars. <<Understood, though once you purchase the necessary tubing adapters your savings may be negated>> On a similar but different topic, I would like to use a cation/anion Deion unit with prefilters and carbon prefilters without the reverse osmosis unit. <<I see...  This is what Anthony Calfo and Steven Pro do...btw>> I was told that, depending on my water quality, with the addition of the reverse osmosis unit my anion and cation resins would last longer. <<They would, yes (hmmm...and I believe it was I who told you this)>> What chemicals or minerals etc. would this depend most on, and what would be the ideal levels of this/these chemicals, mineral,  in order for the addition of the reverse osmosis to not be necessary? <<Even if your tap water were only to contain some calcium and alkaline material, this will exhaust the resins just the same as if it were heavy-metals, nitrates, phosphates, etc.  Most of the "specific" elements of your water are not easily tested/practical to test for by hobbyists (ask for an analysis of your tap water from your water company), and won't matter here so much as the "amount" of impurities in your tap water (commonly/easily tested with a TDS meter).  An RO membrane installed before the resin cartridges will "mechanically" remove many of the impurities in the water leaving the resins to remove only that which is left or "missed" by the RO filter, thus greatly increasing the life of the resins.  The RO membrane will extend resin life regardless of your source water, but obviously is of greater benefit for those hobbyists in areas of "lessened" water quality>> Since ideal would probably be zero, what would be the max levels that you think they could be without the need to justify a reverse osmosis unit? <<Hmmm, an interesting question.  As stated, the RO unit will extend the resin life...period.  I'm venturing a guess here, but if you have a small system/low filtered-water requirement and live in an area with extremely low amounts of impurities in your tap water, say 40ppm or less, you may well find the expense of the RO unit in conjunction with the deionization resins to be unjustified.  I live in an area where my tap water consistently tests at 75ppm-80ppm (not bad at all) and I feel having a combination RO/DI unit is beneficial.  I use a LOT of filtered water (500g reef system) and get 4-6 months use from my mixed-bed DI resins>> Thank you all so much for your wisdom and sorry I have so many questions.   <<No worries mate, I'm happy to help.  Eric Russell>>

Re: DI and Prefilter Cartridges...Need For RO? - 04/20/07 Hello, thank you Eric Russell and others for all your help. <<Quite welcome>> Of course more questions. <<Of course>> Is there good justification for use of RO/DI or will DI be ok based on my local water reports below? <<DI alone is quite effective...some folks prefer this to RO simply as a means of reducing waste water>> I could not find TDS (total dissolved solids?) on my local water report.  What did you mean by TDS in your last reply? <<TDS is a measure of the solids dissolved in the water (water is the "universal" solvent).  Though generally not considered when determining the health effects for humans (which is probably why it is not in your water report), it can be an indicator of the presence of a broad spectrum of contaminants.  TDS is widely utilized by aquarium hobbyists to determine the quality/suitability of their source water; as well as to determine when membranes are bad/DI resins are exhausted, and is quick and easy to measure with an electronic "TDS" meter>> I also want to know if the carbon filter and cation/anion cartridges would last ok if I just wanted to make about 40-60 gallons of water at one time once a month and then store the system dry? <<Hard for me to say...depends much on the quality of the resins and composition of the source water...you will likely just have to "give it a try" and see how things go>> This way I could make my batch of water for the month and store it in a container for use for the month.  Also you suggested the website for resins and there are many to choose from. <<You need to research the different resins and choose that which best serves your purpose...not always the most expensive>> They come in cubic ft. 52 lbs increments, wow how many refills would that be on the standard refillable cartridges? <<A cubic-foot of resin comes to 30+ refills of the standard 10" cartridge...and at about $20+shipping for individual cartridges, is quite an economical alternative...I purchased mine more than three years ago and have more than half left thus far.  If you decide to go with the bulk resin be sure to store it in an airtight/moisture tight container>> Would the Purolite C-100 H cation resin (85$) and the Purolite A300 OHSC anion (164$) in OH form gel-type II work ok together? Are they good as far as your opinion? <<These are fine...do stay away from the sodium and chloride form resins (water softener resins).  But if you are not planning to recharge your exhausted resins (can be a smelly/messy operation that requires purchase/disposal of harsh though albeit usually common household chemicals), I suggest you use the mixed-bed resins for economy/ease of storage and use>> I don't understand the language on this website. <<...?>> Since I only need about 40-60 gallons a month of water, does the resin store ok? <<Yes, if as described>> I'm guessing this amount of resin would last me years and years. <<Possibly>> Thank you so much again. <<Always welcome>> I hope the answers to these questions will satisfy me for a couple days until I generate new questions.  Am I annoying? <<Not at all.  EricR>> Nitrate (as nitrogen) mg/L 0.57-4.54 Nitrite (as nitrogen) mg/L ND-0.02 Fluoride mg/L 0.50-1.21 Sodium mg/L 11-14 Sulfate mg/L 27-32 Arsenic ?g/L ND-5 Common Herbicides: Atrazine ug/L ND-0.39 Metolachlor ug/L ND-0.19 Radiological: Radon pCi/L 86-125 Turbidity NTU ND-.028 Total Organic Carbon (TOC) 1.3-1.5 Lead ?g/L ND-23 Copper mg/L ND-0.24 Total Coliform 2 0-2 Total Chlorine Residual 2.0-4.0 Total Trihalomethanes ?g/L 0.2-0.7 Haloacetic Acids ?g/L ND-0.4 Key: ND: Not Detected mg/L: Milligrams per liter or parts per million ?g/L: Micrograms per liter or parts per billion

Tap water trtmt. for SW    2/12/07 I am in the process of researching a saltwater aquarium setup.  I currently have a freshwater.  The main dilemma that I have is water.  We are in a rural area and have well water.  I have read your book the Conscientious Marine Aquarist.  Several times you mention in the book that you don't contribute water problems so much with the initial water used. <This is so>   I hate to do ro/di water being on a well with the fact that there is so much waste water.   <Mmm, well... could vent the waste water to other use/s... Like out to a trough, or pond...> You also mention several times in the book mixing water a week in advance.  Do you feel that this solves many of the water quality issues?   <Yes I do> Everyone on all the forums says absolutely no untreated water.  What are your feelings on this?  Thanks for your help. <Please take a read here: http://www.wetwebmedia.com/h2opurifiers.htm (the linked files above). Bob Fenner> Is DI enough? Likely so     11/19/06 Hi WWM Crew, I'm trying to purchase a water purifying system for my 75g reef. I will be hooking it up to the waterline that comes in to my house from the city. A local distributor recommended a 3 stage system with 1.) Sediment     2.) DI 3.) Carbon Block. He showed me one and it's pretty heavy duty. It will produce about 35g a day. Are you able to tell me if this is good enough for my system or do you need more information? <This should work out fine... There are other options... but, depending on the make-up of your source water... this approach is very workable> I'm overwhelmed with all of the information available on this topic so I thought it best to just ask. <Would need to know your water make-up, what you're shooting for... I use just RO in San Diego... to greatly reduce overall TDS, sanitizer, dissolved gasses and liquids> Thanks in advance, Bill <Bob Fenner>

Is My Water Really RO Water? 11/12/06 Hello WWM Crew <Greetings>   I was wondering if you could help me out.  I receive 'RO' water once a month from someone who does water change on tanks.  He delivers the water in 5 gallon buckets.  I was just wondering if there is any way that I can be sure that the water in the buckets is definitely RO water and not tap water with Aqua Plus or some other solution in it?  Perhaps I'm paranoid, but I just want to be sure that I'm not being taken advantage of as I am not able to make my own RO water, and I do pay a fee for the buckets I receive. Thank you for your assistance in this matter! Shoshana <If you want to make sure, you can get a TDS meter and test your tap water and then test your RO water.  Depending on the age of the RO filters and whether it is RODI or not, you water should be at least 40 PPM or less, preferably 0 PPM.  Cheers! -- Dr. J>

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

RO System Output...Possibly Damaged or Faulty Membranes - 09/27/06 I am having a problem with my RO system. <<Oh?>> I have a Kent 200gpd system with an add-on DI. <<Big system>> I store all in a 200G plastic tank.  After replacing all the cartridges (including membranes) it will run great with the TDS reading 0. <<Good...>> But within about a month I notice that the RO unit is producing water much faster than usual (it normally produce about 125-150gpd) and the TDS is up to about 140 which is about the same as tap water. <<Mmm...not so good...>> I change the sediment and carbon prefilter about every 7-10 days, because I read you should change them every two to three thousand gallons. <<And you produce that much filtered water in a week?...wow>> It seems as if the membranes are failing. <<Indeed...am in agreement>> Any help would be appreciated. <<A couple things come to mind...Firstly, I would try a different source for obtaining membranes.  Next, make sure you are getting 'TFC' membranes as opposed to 'CTA' membranes.  The CTA membranes break down very quickly if exposed to chlorine, and if your carbon prefilter is not adequate at removing this, well...  Also, rather than using the sediment prefilter, consider using "micron rated" solid carbon blocks.  Using a 5-micron block as your first-stage and a 1-micron block as your second-stage will still filter out particulates while providing some additional chemical prefiltering of the water before it reaches the membrane.  Most carbon block combinations such as this will usually give you in excess of 5,000 gallons usage, and I seem to recall some with 30,000 gallon usage ratings (these blocks can also be easily rinsed of loose sediment on a weekly/monthly basis)>> Thanks, Daniel <<Hope this proves helpful.  Regards, EricR>>

Re-2: A Tale of Two Dead Naso Tangs   9/19/06 Hello Eric, <<Hi Patrick>> I searched your site and was unable to find articles on RO top off pro/cons but going through some other users' questions have a basic understanding of the concern of not using raw RO. <<Ah good...and maybe time for me to stop procrastinating and "put pen to paper" re.  And here are some articles worthy of your perusal:   http://www.wetwebmedia.com/water.htm ... http://www.wetwebmedia.com/water4maruse.htm ... http://www.wetwebmedia.com/ca/volume_2/cav2i4/RO_systems/reverse_osmosis.htm ... http://www.wetwebmedia.com/watchgantart.htm ... http://www.wetwebmedia.com/marine/maintenance/marineMaint.htm>> I am without question going to change my procedures on the water change water, actually I understand now why I have to keep adding alk buffer as much as I do. <<Indeed!  Considering the volume of the tank, your water change routine, and the fact you have but a few corals at present, regular supplementation of earth elements should not be required>> Some new challenges are with the top-off water. <<...?>> I have serious space issues and need to find more information on what other people are doing to pre-treat their RO top-off water. <<Should be mentioned in one or two of the articles I've provided.  But is a simple matter of utilizing a suitable storage container (plastic trash cans are common) to hold the RO water, adding aeration/water movement for 24 hrs to blow-off CO2, then adding buffer to raise pH and alkalinity.  I like to use a 2 to 1 mixture of baking soda and Seachem's Reef Buffer...you can use baking soda alone but you won't get much of a pH rise without "baking it" first (spread on a baking sheet and bake at 300 degrees for 1 hour) to drive out the CO2 used in its manufacture>> <Interesting. Making some of this sodium carbonate... RMF> The RO unit has an ASOV (a fast flush as well, forgot to mention previously) so putting a float switch in the sump was not a problem. <<Understood...and not an uncommon though ill-advised practice>> What are some standard solutions, mechanisms used? <<Whatever your imagination/budget allows.  My configuration consists of a 55g polyethylene barrel sited in my garage which is fed automatically by my 5-stage 100gpd RO unit.  I control water flow to the RO unit through use of an "air-pressure" water-level switch that turns power on-off to a solenoid valve I installed between the water line and the filter unit.  The 55g drum is plumbed through the attic to a 20g reservoir positioned above my display tank.  A push-button "momentary" switch allows me to easily and conveniently fill the reservoir from the drum in the garage.  Top-off to the sump is controlled by a Tunze Osmolator which feeds water from the reservoir to the sump through a DIY Nilsen reactor (use of the reactor precludes the need to buffer the water beforehand).  This was "my" solution to the "top-off" issue...think about your needs/what you want to do and come up with an idea/a plan and I'll be happy to discuss it with you>> Seems to me I would need a container of some sort with a pump and float switch and a level controller in the sump? <<See...you're half way there <grin> >> Any help in the area would be appreciated.  Just an FYI Big Al's sells Tropic Marin fairly cheap.  A 200gal mix shipped is around 60 bucks. <<Not bad...but still decidedly more than Instant Ocean...which I also consider to be an excellent and consistent salt mix...and probably the best value for the dollar re>> I don't know if I feel any better having a better understanding on how the tangs died, but I walk away knowing more about a number of things and plan to make a number of changes based on your advice. Thanks <<Is all we can do my friend.  And the more we learn...the better we come to understand...the greater the benefit to the hobby will be.  Regards, EricR>> RO Water  - 09/14/06 Hi Crew, <Mr. C> I have a couple questions about RO water. For a simple fish and  invertebrate system, with a couple of hardy corals, is RO water really  necessary? <Mmm, nope... depends on what your source water is, what otherwise you want to do...> I feel it might help out a bit. For again, a simple fish and  invertebrate system, would 3 stage RO be fine, or do you NEED the 4th stage,  deionization? <No> Would my system survive if the 4th stage is not provided, and well  water is used? <Very likely so> I talked to a fellow hobbyist and he said he believes using well  water with a RO system would be better than city water because it doesn't  contain all of the chloramines and such. Is this true? <Unless one is adding chloramine...> Doesn't well water have  more minerals though? <Not all... too many vague generalities here... There are tapwater's that are quite mineral laden, and relatively soft wells> Also, what brand of RO filters would you suggest for  someone who has a fairly small (36 gallons) system? Thanks a ton! <A cheapy Home Depot or equivalent unit. Bob Fenner>

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>>

Retail RO/DI   9/1/06 Hi Bob: <Greg> I have been doing a lot of research on large capacity RO/DI systems (I guess "large" is relative though!!).  Do you have any suggestions/preferences as far as brands, expense to operate, etc. of the various 500-1000 gpd systems designed for retail applications? <Mmm, would have to take a look see with such descriptive terms on the Net really...> I've seen quite a few but lack the experience to know what the real differences are.   Thank you, Greg. <Some units have "more" filtering modules as pre-filters, contactors... and some profess more material removal... but capacity, cost to obtain and operate (the availability of new membranes and cartridges importantly) are the most important considerations by far. As with most all "gear" questions, I'd "shop" this around on the various specialty BBs (ReefFrontiers, reefs.org...) and ask other aquarists what they've (recently) purchased, used. Bob Fenner> What would you do?  An experienced point of view needed please. When in doubt, your own R.O.   8/23/06 Hello crew, Need help here as soon I will be using my current 84 gallon tank as a quarantine and graduating to a 480 litre (English measurements) tank as my main one. I have been using R.O water on my smaller tank and of course everything has much improved especially my phosphate and nitrate and no doubt my fishes health too. I would like to use the R.O water on my soon to be new tank but financially it would appear that it may be more costly than I first realize. <Mmmm> I understand that with larger systems the nitrates etc tend to rise slower therefore sometimes requiring less frequent water changes, <Mmm, depends on what's in them... how much... what fed... what filter gear employed... mostly> perhaps once per two weeks or even once only per month in some cases? <Yes> I may end up buying an R.O unit, <I definitely would here> my LFS are hoping to strike a deal with someone where the units will drop from about 100 - 150 to about 50 - 90 £. <Look to the large hardware, "home" stores here... there is nothing "exceptional" re the "fish store" units and the ones meant for home/potable use> This, though, will be a few months away. Attached to the mains drinking water I have a very high quality ceramic filter. Perhaps as it was quite satisfactory for my small tank it will therefore be even a little more acceptable for my larger tank when it arrives? <... Worth having the resultant water quality checked... I would get/use my own R.O. unit if there were any prominent issues with your/my source water... for pet-fish and my cooking and drinking needs. Bob Fenner> Kind regards team. Steve. RO/DI...Misapplication/Buffering/pH - 08/09/06 Dear Crew: <<Lloyd>> Hi.  I just set up my first marine tank over the last two weeks and have some issues. <<I see>> The tank is a 180, and will be a FOWLR if I can ever get to that point. <<Let's see what I can do to help you get there>> I filled it with tap water, which is relatively clean, but hard.  Alkalinity was at 300 KH and pH at 8.4.  I treated it with Amquel Plus, added Oceanic salt, (SG is .019), and put in 120 pounds of CaribSea Geo Marine crushed coral with aragonite. <<I know this is a FOWLR system, but I really think you should increase the salinity to natural seawater levels (1.025/.026).  If parasitic infection is a concern then arm yourself with a quarantine system and read up on/perform freshwater dips when transferring your fish, but don't subject them to a continuous hyposalinity environment in the display.  Think about it, another term for hyposalinity is OST or Osmotic "Shock" Therapy...it has its uses for some short-term treatments, but not as a permanent environmental element.  Your fish will exhibit better behaviors, colors, and "long-term" health in my opinion if kept at a salt concentration closer to/matching that from which they came>> I washed the gravel extensively but still have somewhat cloudy water.  Should I use water clarifiers or just filter it out mechanically with a 50 micron pad? <<Nix on the clarifiers...you can use the filter pad if you wish, or just wait for the "dust" to settle on its own...usually a matter of days>> My more distressing issue is with pH.  I have been reading a great deal in the FAQ's regarding the use of RO/DI units and how they affect water quality. <<Can...if misused>> While I certainly may have missed something, (yes, I used the search tool), I seem to be finding conflicting information. <<Differing opinions abound>> I am currently running RO/DI water directly into my sump to top off one to two gallons per day as a result of evaporation. <<Yikes!  This is an example of "misuse"...adding raw unbuffered RO water to your system contributes to the rapid depletion of buffering elements as your system tries to make up for what the newly added water lacks>> I read that this is an acceptable practice, <<Mmm, no...not in my opinion...a recipe for trouble>> however, my pH has dropped into the 7.4 range and the alkalinity is at about 80-100 KH. <<And there is your proof my friend.  If you are going to run the RO/DI water directly to the tank then run it through a Kalkwasser reactor first...else I recommend you discontinue this practice and store/aerate/buffer the water in a separate container before adding to your system>> I have also read that processed water often has a very low pH and that it should be aerated to dissipate CO2, which "consumes" alkalinity, which would seem to confirm my problem. <<Aerating/dissipating CO2 will provide a small increase in pH, but you will still likely need to give it a boost...and you still need to boost/buffer alkalinity>> I'm a bit confused. <<Have you read here:   http://www.wetwebmedia.com/marphalk.htm >> By the way, I'm using Jungle 5 in 1 test strips, so I'm not positive about how accurate these are.   <<Useless...low quality/inaccurate, too easily affected/corrupted by atmospheric moisture.  Do look to Hach, Salifert, and Seachem for good test kits>> I have a reservoir for mixing salt water and would prefer to use tap water, mixed and aged, for water changes only and continue to run the RO/DI water directly into the sump with the use of a float valve. <<Depending on the water in your area using tap water for a FOWLR system is quite possible, but running the raw RO.DI to your sump for top-off is not...in my humble opinion and for reasons you have already experienced>> This will allow me to minimize my use of the filtration unit and save having multiple floats and pumps, while still maintaining an automated top-off. <<But at the expense of system stability an the associated detrimental affects on your livestock>> Should I use additives to raise pH and alkalinity or is there a better method? <<Using additives to "continually" adjust pH and alkalinity in your system creates a roller-coaster effect that will surely have deleterious affect on your livestock.  The "better method" is to adjust pH/alkalinity prior to adding the water>> I have a general aversion to using additives of any kind and seem to remember reading that manipulating levels in this manner is to be avoided. <<Indeed>> What to do? <<Already stated>> Thanks for any help that you may provide.  I had hoped to not bother you with an e-mail and find answers on my own, but the more I read, the more overwhelmed I am with the vast amount of information. <<No worries mate...am here to help>> I have been reading on your site for a year prior to undertaking this project.  I also refer frequently to Bob's "Conscientious Marine Aquarist". <<Ah, very good...but don't limit yourself to a single source of information.  You've already noticed the differences in opinion just on this site...best to gather/learn from differing sources and use your own good judgment to make a decision>> Both have been outstanding sources of information and I appreciate the time and dedication that all of you put into this hobby, or in your case, profession. <<Mmm, not my vocation but more an avocation...no "expert" here, merely a "student" of the hobby>> Thanks again, Lloyd H. Columbia, MO <<Happy to assist.  Regards, EricR in Columbia SC>> Zero-Waste R/O Units...Marine Stocking/Refugium Questions - 07/30/06 Hi, <<Hello>> I am new to this hobby, and have a few questions. <<I'm here to assist>> First, I have a 150 gallon aquarium, with a forty gallon sump and a 20 gallon refugium. <<Cool!>> I am going to buy a RO unit because I am already tired of hauling RO water from the LFS and I know it will save money in the long run. <<Ah yes, not to mention giving "you" control over the quality/purity of your water>> Do you know anything about the "no waste" RO units that are on the market? <<Just what I've read on the internet>> Would you recommend them? <<From the little I know...no.  Depending on the model, it appears these units either feed the "waste" water back in to a hot water line, or back in to the cold water line feeding the RO unit.  The first method means the concentrated waste water can get in your cooking, your dishwasher, your shower.  The second method has these same issues to include drinking water...along with much quicker exhaustion of the filter components.  The decision is yours to make, but I prefer to let my RO unit flush the waste water to my garden.  If you do decide to go with a zero-waste unit, I recommend you check with your water company to see if they will require you to have a "back-flow preventer" installed (at your expense) on your home's water supply line coming from the street to prevent back-washing/possible contamination of the municipal water supply>> My next question is regarding stocking.  I have about 200 lbs. of live rock, a Majestic Angel, one Sohal Tang, one Copperband Butterflyfish, one Scooter Blenny, a pair of Percula Clownfish, one Royal Gramma, one Spotted Mandarinfish, a Mystery Wrasse and a Sixline Wrasse.  I would like to add a small school (5-7) of Pajama Cardinals, would this overload the tank? <<Is probably fine>> (I have an AquaC Remora 180 skimmer.)  My last question may seem silly, but will the small and micro organisms from the refugium go through the plumbing, with the water, into the main tank? <<Not silly at all, and often up for debate re the "survivability" of these organisms when passing through the pump.  I'm of the opinion that concern over "impeller-shear" is over-rated...most organisms will pass through the plumbing just fine.  So to answer your question...yes, the biota generated by the refugium will make its way to the tank>> I am so glad I found you guys. <<We're glad too!...and ladies here as well>> I live in Montana and there is no reef society, that I know of, here. <<Mmm, there is the Idaho Marine Aquarium Society ( http://www.idahoreefs.org/) which I believe services portions of Montana...worth making contact>> I'm doing this by myself and am getting my information from books and the internet. <<Indeed...making use of the resources at hand>> The LFS isn't very knowledgeable. <<A shame...>> Thank you for all your help.  Linda <<Is my pleasure.  EricR>>

RO Filter from Lowe's - 07/03/06 Hello All, <<Greetings>> I tested my source water (well) and found the PO4 >= 5.0ppm. <<Yikes!>> I was at Lowe's and found an R/O system with 5 gal storage canister for under the sink. <<Yes, have seen similar>> I do change 5G every week, but also replace about the same from evaporation.  I can easily replace evaporate the day before water change and do just fine with drinking water use as well. <<Mmm, I would replace evaporate on a "daily" schedule at the least...will help to keep water chemistry from fluctuating more than necessary>> My question is whether a whirlpool WHER 25 removes phosphates/phosphorous? <<Yes...as well as about any RO membrane will.  These membranes are likely the same membranes you'll find in some "aquarium" RO units...just marketed under different names>> There is nothing specific about PO4. They do talk about Total Dissolved Solutes, ionic materials, chlorine, organic impurities (probably the one I am interested in ) etc. <<Nevertheless...the unit will definitely make an improvement with your well water>> I sent an email to Ecodyne, Inc., the mfgr.s of the unit to no avail.  I am smitten with this unit cuz it has everything I need to hook it up...all in one box, and priced well.  Any suggestions, recommendations, advice? <<I say 'get it!'...it will work as well as any bare-bones "aquarium" RO filter.  Regards, EricR>>

Low Cost Water Purifier Sought    6/26/06 Hello, <Hi Robert - Tim answering your question today!>   I'm looking to get a decent ro unit for my nano reef as the water  quality is rather bad where I live.  I'd like a Spectrapure unit,  but they are somewhat out of my budget.  Any suggestions for an  alternative low cost quality purifier?  Thanks. <Unfortunately when it comes to RO units, in most cases, lower cost translates to some extent to lower quality. If you are requiring RO water only for use in your nano reef I would very much suggest you contact your LFS. They will commonly provide you with RO water for little or no cost.>   Robert

Tap water purifier, product    6/4/06 If anyone is using the Tap Water purifier, make sure the replacement canisters you buy have GREEN resins, not gold! A few years back I had bought one without looking at the canister in the box. When I brought it home, I noticed they were gold. I ran it anyway, and noticed algae beginning to grow, as well as other signs that something was wrong. When I checked the silicate levels, and other parameters, they were high. The owner of the store told me the resins turn gold when they are old. I e-mailed Aquarium systems who make them, <... TWP is made by Aquarium Pharmaceuticals...> and they told me, "These are the new gold resin filters we make." This is the kind of people we're dealing with. I don't know about you, but $25-$30 a canister is a lot of money for me. Just thought you might be interested in knowing.                Eddie V. <Am not a fan of these units period... too expensive for what they do, slow... Bob Fenner>

RO vs. DI (Waste Water)- 05/19/06 Hi WW crew, <<Hello Bonnie>> I currently have a Spectra Pure 4-stage RO/DI unit. <<Nice units>> Works great, however, I just received a notice from the County that the homes in my area will no longer have a flat-rate water fee. <<Bummer>> They will be installing water meters on all the homes. <<Only way I've ever seen/experienced it done>> I'm concerned since I know this current RO/DI unit has a ratio of 1:4  (for every gallon made, 4 gallons is wasted). <<Typical>> I'm thinking of buying just a DI unit, but I can't seem to get any clear answer as to what the percentage of waste water on a DI unit is in comparison. <<Is virtually "zero" waste as compared to the RO unit>> I don't believe the DI units are as thorough in removing all the impurities either. <<Mmm, not true...the Kati-Ani units are quite good/efficient at removing a wide range of impurities...Anthony (Calfo) swears by them.  And according to him, if you buy the German made resins, they will last for years (with recharging as needed of course>> Any suggestions would be appreciated.  I have a 30 gallon reef tank which is doing great and do not want to compromise the water quality. <<To be honest, I don't think you have to be too concerned over the RO unit.  But if you want to make the change, a quality Kati-Ani DI unit will give you many years of service>> Thanks, Bonnie <<Always welcome, EricR>>

RO/DI kills corals? - 05/16/2006 Thanks for all the great tips!  I've been fighting hair algae for months now and decided to take the plunge and purchased a ro/di unit from eBay.  My procedure for water changes was to make 10 gals. of RO/di water and let it set for at least 2 days.  Then add salt, buffer and aerate one evening.  The next evening I would fine tune the salinity and heat the water - usually using it in about 3 hours.  I try to change 10 gals. each week in 40 gal. tank.  Well the first change went fine and the corals all opened up and looked good.  The next change they closed up for a couple days then ok.  The next change they would not open at all, then the flesh started falling off!! <Yeeikes!> I stopped using the RO/di and have gone back to tap water, however all the corals are now dead.    My testing and LFS showed nothing wrong with any parameters except a dip in salinity 1.019 that I corrected in a couple days. <? Better to pre-mix synthetic water for a week or more... make sure the specific gravity is matched before using...> I've had little trouble with the system for 3 years until now (except the #$#%##@ hair algae)  What the heck did I do!!! <Don't know... the new water may/perhaps be totally unrelated to the losses... But I would test some of it, or have it tested, to assure something is not amiss here. Bob Fenner>

Re: RO/DI kills corals?   5/17/06 That's probably a very good idea.  How/where do you get water tested? <Mmm... a Quality Assurance Lab (you can find through your "Yellow Pages" under this title or "Water Testing"... or your own hobbyist kits... for pH, nitrate, phosphate will likely give an indication of what is at fault here... a membrane, possibly a contact filter...> I've read the threads about mixes being 'toxic' but after a week in the tank shouldn't that correct itself? <Mmm, depends on the root/cause... if something is being imparted to the water by the filter itself... possibly not> In other words shouldn't the corals have recovered after a few days of mixing in the aquarium? <Sometimes there is a "cascade effect" of such animals dying off... that takes the rest with them... especially a problem in smaller, less-filtered, balanced systems. Bob Fenner>

Re: RO/DI kills corals?  - 5/19/2006 Thanks again for your kind help, but now it's all over! I decided to tear the tank down and start over.  That way I could brush all the hair algae off my live rock.  While emptying/cleaning the tank I noticed a foul smell, so I think like you said I had to much die at once and an ammonia spike followed. <Very common>   Anyway I set up a 10 gal. tank for the remaining 2 fish.  I used 5 gal of RO/DI, 2 gal. of distilled water, and 2 gal of tap. I added the salt, aerated and heated for 3 days.  I put the fish in the small tank and they died overnight.  Now it could have been stress, but the other changes are I switched to 'Reef Crystals' (on sale) and the RO/DI. I've contacted the supplier and he said that the RO/DI seems to be functioning correctly - 1.5 gal pure for 5 gal. waste water.  Have you heard any problems with Dyoneb filters from eBay? <Mmm, no... but I would have your water tested... before and after going through these... and NOT drink/use the water for comestible purposes till you have> It's kind of late but I believe that the hair algae problem was because I didn't have enough water movement. Only 1 small power head 150/hr I think.  One of the LFS has only used tap water for over 30 yrs. in the hobby. <Is "good to go" in most localities... as you will/would see my opinions re if you read on WWM re> Our city has very good water and the only problem besides the chlorine is nitrates and phosphates.  I know that the phosphates average around .2.  So do you think I can use the tap water? I sure hope my wife lets me start over again..... <... Please read here: http://wetwebmedia.com/water4maruse.htm And the linked files above... Bob Fenner>

RO/DI unit membrane change  - 5/8/2006 At which TDS reading should one change the membrane of a RO/DI unit?  I've had my unit for just over a year and my reading on my meter reads 75ppm IN, and 40ppm out.  I tried flushing out my membrane several times.  I'm thinking this is what is contributing to my Cyano problems.  I've eliminated all other reasons Cyano.  What do you guys think? Nilesh <Nilesh - Assuming your TDS meter works fine, most people strive for an output of 0-3ppm.  Thus, 40ppm is quite high.  After 6 months to 1 year, many manufacturers recommend changing all the filters/membranes.  However, it really depends on the system, overall use, and your water supply.  If you had been testing with the TDS meter since the beginning, you could have seen the water level decline over time and be more certain that you need to change the filters/membranes.  At this point, I would suggest making sure the TDS meter is working properly by checking it with distilled water (it should be close to 0ppm).  If it is, contact the RO/DI manufacturer and see what they recommend you replace.  My guess is that without being able to test each component individually, they are going to recommend replacing all of the filters/membranes.  If so, then you can test the output with your TDS meter and develop a baseline to monitor over time.  Due to variations in water supply and plumbing, everyone's input and output TDS readings are different.  However, the input TDS should remain relatively constant for you over the course of the year.  Once you know your individual situation, you'll be able to figure out how often to change the components going forward.  Best of luck, Roy>

RO, RO/DI, or DI   4/28/06 Hi Crew, <Cindy> I love this website.  I've learned so much! <Ah, good> I have 5 cichlid tanks (50g, 29g, 20g, 12g, and 10g). We started with a 50g and you know how it goes, one tank leads to another. <Oh yes> We've been buying R/O water from a purified water store and hauling it home in 5 g. bottles. <... I would buy, install, run your own Reverse Osmosis unit> It's a real pain in the neck and because cichlids are messy I am having to do 50% water changes weekly. <Okay> I developed a bad case of tendonitis (tennis elbow) from lifting so many 40 lb. water bottles (I'm only 5'3" and 108 lbs) so it's time I purchase a filtration system.   <Yay! They're easy to install, use> I've read through your website and I'm still dazed and confused over methods of filtration. You make many references to RO wasting an obscene amount of water. What is an obscene amount? Is the ratio 4 to 1, or what? <Very often something like this... however, the vented, a bit more solute laden waste water can be used for other purposes, types of cichlids...> If so, are the RO/DI units more efficient, or are the ratios the same? <The same> What about DI waste? <Less...> Can you give me rough estimates of the ratios for all three types? <Variable per the make/model used and your particular water quality...> Since I need to make at least 60g per week I don't have enough uses for 240g waste water (even if I used it for laundry and the garden - especially living in Seattle where we have so much rain!). <... are you sure you need this water period? What types of cichlids, what is the make-up of your source water?> I've just begun raising cichlid fry so I really want to invest in a good system and am not willing to take chances with tap water. Cindy (Cichlids in Seattle) <Was up there a couple months back giving a pitch at a marine club... and drinking the tapwater... Let's chat re. Bob Fenner> Re: RO, RO/DI, or DI  4/29/06 Bob, <Cindy> I feel honored that you replied.  I read your website all the time and I'm forever quoting you. <Ahh!> I've read many of your magazine articles.  Have you published any freshwater books? <No... or perhaps "not as yet" is more accurate> Amazon only stocks two marine books you've written (one with Anthony Calfo).  I'm always wanting to learn more as I've only been into this hobby 2 years. We started 2 years ago with a 50g stocked with the following: 1 Astatotilapia latifasciata (Zebra obliquidens) 1 Aulonocara stuartgranti (Rubescens) 1 Labidochromis caeruleus " Yellow Lab " 1 Melanochromis auratus 1 Metriaclima callainos "Cobalt Zebra" 1 Metriaclima estherae "Red Zebra" 1 Placidochromis electra "Deep Water Hap" 1 Pseudotropheus demasoni 1 Pseudotropheus socolofi <Very nice mix> Magnum 350 canister with Bio Wheel Fluval 3 Stealth heater I know these canisters are a pain - but I figured out how to prevent the carbon canister from imploding by opening the intake and outtake tubes and releasing some of the canister water through them prior to taking off the lid.   <Good technique> I must admit I am certain I am overfeeding to cut down on aggression.  Most of my cichlids in my 50g have grown to 4 to 5 1/2" long and are male except for the Zebra Obliquidens. 4 months ago the peacock (Aulonocara Ruben Red) was attacked by his tank mates.  I didn't think he'd make it through the night but I moved him into a 12g QT and dosed him with erythromycin to prevent secondary infections.  He survived and I didn't have the heart to put him back in the main tank so I decided to leave him there alone. <Mmm...> 2 months later my Zebra Obliquidens came down with a bad case of Malawi Bloat. I moved her into a spare 20g someone had recently given me.  I treated her with Metronidazole and fed her some peas.  I searched your website and began suspecting intestinal parasites (she had been passing stringy feces) so I treated her again 2 weeks later with Kanaplex for good measure.  She has a great personality and is always on the go dancing around the tank and in and out of the bubbler.  She's never exhibited any aggression towards the others, however, her tank mates have interpreted her wild behavior otherwise.  Her tank mates seemed happier without her so I left her in the 20g. Meanwhile, the peacock was outgrowing the 12g so I bought a 29g and ordered two female Ruben Reds for companions.  The females arrived before the 29g was ready so I placed them in the 12g and soon after one of the females was holding.  I did an online search and saw somewhere that it takes 3 weeks before the fry are released (turns out they actually hatch at 15 days).  My plan was to leave the mother in the 12g and move the male and other female into the 29g.  Approx. 2 weeks later she began eating again so I suspected (she's young) that she'd eaten the eggs and so I moved the whole crew into the 29g.  9 days later I discovered several fry in the tank.  Their egg sacs were gone and they were foraging for food.  Being the weak heart that I am (I'll stay up most of the night with a sick fish) I couldn't dream of leaving the fry in the tank and taking chances they'd be eaten.  I ran out and bought a 10g and proceeded to strip down the big tank (moved the adults into a bucket) and searched with a flashlight (to distinguish the fry from the gravel) and recovered all 8 remaining fry.  I'm happy to say that they have now all been thriving for 3 weeks in their grow out tank. <Good> Meanwhile I decided to get a male for the female Zebra Obliquidens.  He's been living in the QT tank for 2 weeks now.  He's much smaller than the female so this will be a challenge.  I plan to set up an egg crate partition and move him into her tank and give it a month or two and see if she'll calm down enough to accept him.  He's gorgeous and all colored up, but at most 1/3 her size.  If it doesn't work out I may have to return him to the LFS as caring for all these tanks has become a full time job. <Can be so... am always keen to discover, implement more automated, simpler maintenance...> During all of this (5 weeks ago) I had surgery.  This laid me up a bit and the tank conditions deteriorated for a time and I lost my Demasoni.  He was one of my favorites.  I felt so guilty.  He was also my nitrate indicator. I could always tell when nitrates were getting high (although I do have a test kit and use it) because he'd hide in his cave and not come out for food.  This was tough losing this guy.  He had such a great personality and it amazed me how he wasn't intimidated by all the other big fish.  I had recently noticed that he was becoming more timid at feeding time (now that the others are so big) and I was having to add extra small sinking pellets for him.  I had begun questioning the decision to keep him in that tank.  I certainly was over feeding because I was afraid he wasn't getting enough food (the big guys would crowd at the water line and snatch most of the food while he'd swim around the bottom looking for morsels).   Here is what I am running on my other tanks: 29g Emperor 400 Fluval 2 Stealth heater 20g Penguin 150 Fluval 2 Stealth heater 12g Eclipse 12 (built in filter) Fluva1 1 Stealth heater 10g Penguin 100 Stealth heater I am open to any suggestion for better filtration as well as what you recommend for water filtration.  As my 50g is the most heavily stocked it is the messiest tank.  I plan on getting rid of the Magnum 350 someday anyway. I've also been wondering if adding a skimmer might help. <Mmm, no. Not likely much on a freshwater system> Sorry for rambling on so much.  I find this such a fascinating hobby.  When I get into a hobby I go overboard.  I'm even educating guys who've been working at my LFS for years with the information I've gleaned off your website!   <Good for you, them, the planet> Oh, by the way, I just bought Boyd's Chemi-Pure and put it in the Fluval in my 20g (which was on the verge of needing a water change) and it was like giving my Zebra Obliquidens Prozac. <A wonderful product> She's been acting skittish lately and she's back to being sociable again.  I'm definitely going to be adding some of this to each of my tanks!!! Cindy (Cichlids in Seattle) <I would keep looking about for larger tanks... consider keeping the Aulonocara separate... Bob Fenner> Brass RO fittings - Metallic float valve on an RO system  - 04/27/06 Greetings from sunny (finally) Colorado! <Hello! John Hee from warm and hazy Shanghai.> My question concerns using a float valve with metallic parts on my RO system reservoir.  All of the tubing and fittings exiting my RO system are plastic, with the exception of the metallic float valve assembly (the float is plastic, the valve body is brass) on the reservoir barrel. My reef tank is looking very healthy after a year of using the metal float valve-the pods, corals, snails, fish, mushrooms, etc. are thriving.  Some members of our local group tell me that the all-plastic floats are necessary, but I can't find anything, fact-based or anecdotal, on the web indicating that this float valve will contaminate my RO water with copper.  I like the feeling of security from flooding vs. the prospect of plastic part failures.  What are the facts? <I think you have the facts: your reef tank is looking fine! On a more serious note, if the valve is being used for RO-only (as opposed to Deionized) water, then you are unlikely to have any problems. Visual inspection for rusting of the brass component should verify this. Brass is not usually recommended for DI water, as the DI water is too reactive. That said, I myself have used solenoids with a small brass fitting for several years with DI water and have not had any problems. Of course, brass should never be used in or around your tank water or salt water. If those float valves are sitting in the reservoirs after adding salt (or indeed sitting in RO/DI water for a long time at all), this is a no-no. However, to put this in perspective, I've never had or heard of problems with plastic aquatic float valves that you allude to. Best regards, John.> Adjusting pH on RO/DI Effluent - 04/24/06 Hello WWM Crew, <<Hello!>> Great to be talking (typing) to you guys again.  I have a question for you as to how you might go about treating the water leaving an RO/DI filter used for automatic top-off. <<Mmm...>> The filter is plumbed to a "T" connector in my basement.  One effluent line connects to a float-valve in an aerated 42 gal trash can in the basement that I use for water changes, the other line runs to another float valve in the refugium under my tank, both floats are working well and all water levels are stable.  The tank is a 72 gallon bow-front reef with LPS corals and fish.  My concern is stability in the tank, most specifically PH. <<Ok>> The RO/DI filter is continually topping off my tank with water of a very low PH. <<Indeed...as well as no buffering capacity and little to no oxygen content>> Tank measurements for PH are running about 8.2 during the day, but are dipping to 8 at night. <<Not that bad really>> I have never had this problem before, so I am attributing it to the fact that I am now feeding the make-up water directly into the refugium without buffering. <<Yes, probably so>> My RO/DI filter is a six-stage setup that finishes the treatment with two REFILLABLE DI chambers, both utilizing the same type of resin.  My thinking was that I could remove the resin from the last DI chamber and fill it with washed aragonite or some other sort of slow-dissolving mineral that would boost the PH of the make-up water prior to releasing it into the tank. <<Maybe, but I'm skeptical the sand will make much (enough) difference...perhaps if finely ground>> Whatever is used would need to dissolve slowly because water sits in the cartridge all day and is released into the tank very slowly. <<I recommend you place about a cup of Kalkwasser in the last chamber.  This configuration would work similar to the Tunze Kalkwasser dosing system: https://www.marinedepot.com/aquarium_dosing_pumps_top_off_tunze_osmolator.asp?CartId= >> I love the auto-top-off in that it keeps the salinity in my tank at a very stable level and reduces the number of trips I have to make up the stairs with a bucket of make-up water, but I do not like the idea of putting water into the system without buffering it first. <<Nor do I>> Do you think that this would work?  Would you use aragonite? <<I would try the Kalkwasser>> Do you know of anything else that may work better?   <<Dosing through a dedicated Kalkwasser reactor such as this ( https://www.marinedepot.com/md_viewItem.asp?idproduct=PM4111), but I think just adding some Kalk to the last chamber on your filter unit might do the trick...would save the added expense of a reactor>> Any insight you can offer would be greatly appreciated! Best Regards, Bart <<Cheers, EricR>>

RO/DI...It Wastes a Lot of Water! - 04/22/06 Hello, Thanks again for all you guys do! <<Ah yes, you're welcome...but don't forget the ladies who make a huge contribution here too!>> I just purchased a used Kent Marine Maxxima RO/DI unit, got it all hooked up fine. <<Ok>> I have one question though, this seems to put out a lot of waste water, it will run probably 5 gal of waste per quart of good water... <<Indeed...is how these units work>> Does that seem right or is something real wrong? ( I have never used an RO/DI so I have no idea, it seems like a lot of waste to me) <<Is a lot of "waste" yes...but nothing is wrong.  For this reason, some folks opt to use quality regenerable Deionization filters (Kati/Ani).  Have a look at these links to get a better understanding of how an RO filter works: http://www.wetwebmedia.com/ca/volume_2/cav2i4/RO_systems/reverse_osmosis.htm http://www.wetwebmedia.com/rofaqs.htm >> Water pressure is about 67 psi (according to the only gauge I have), the manual says it should be about 65 so I think that's right in the ballpark. <<Agreed>> I also took out the resin cartridge and ran it overnight like they suggested for new installs.  One other question, Mag 12 pump vs. the Via Aqua 4900, the Via Aqua is about 1/2 price, will the Via Aqua be OK for a return pump (from the sump to the tank) or should I stay away from it and go with a Mag 12? <<I have used both, my preference is the MagDrive pump (have had one running more than two years now)...you will find the Via Aqua to be very, very noisy.>> Thanks again, Mike <<Very welcome, EricR>>

Storage of RO Water  - 04/19/06 Hi Crew, <Chris> Hopefully I wont be banned for asking 2 questions in the same week :-) <No one has been... yet> Just a quick one about storing RO water for top-ups. Can RO water be stored in a sealed container with no aeration for a week without affecting the quality of the water ? <Mmm, yes... though should be aerated, checked for quality ahead of actual use...> I have an auto top-up system that tops up the main system from a 25litre container of RO water and I use 2x 25litres containers on a rolling basis, so one is always sealed and stored for about 6 days before it is used. Do I need to find a way to aerate the water while in storage ? <Mmm, in this/your case, not likely... as the amount delivered, though itself has little to no dissolved oxygen, will not affect overall DO> What about the active container that the auto top-up system is connected to ? <Again, no worries. Bob Fenner> I have to say I spent 90 minutes searching for the answers, but couldn't find anything that would give me absolute clarity :-) Thanks Chris Store-bought RO water - 15/4/06 Hi WWM, I have been using RO water in my 40 G reef for about two months. The H2o is store bought and is by great bear water co. It says on the package that it it purified via reverse osmosis. But the source is well water. Is this safe to use in my aquarium? <Likely fine. However, I would concern myself more with the result than the source. Do test the RO water for common nitrogenous wastes, and TDS. I found I had to subsequently purify my RO water through deionization before it was as pure as I would like it -- but I have particularly nasty tap water.> Livestock: yellow tang, watchman goby, domino, clownfish. Providing that : it is buffered and aerated before it is salted ? Thank you ahead of time John Ferrante <Thank you for writing. Best  regards,  John.>

Equipment/RODI    3/29/06 Hi Bob,  <James with you today.> I couldn't find the answer to my question on the site...so I apologize if I'm repeating a question.  <OK> I recently bought an RO/DI unit. I was using distilled water before. The TDS on the product water of the RODI is 0.  For top-off water, I added 2 teaspoons of baking soda to 5 gallons of water to buffer.  The PH is around 8.3, but the TDS has jumped to 221! With this level of TDS... Is this normal?  <Yes, you now have dissolved solids in the water.> Is this water safe to use as top-off?  <Certainly.> Thanks for your help!  <You're welcome.  James (Salty Dog)> Wayne Re: Equipment/RODI   3-28-06   Hi James  <Wayne> Thanks for your prompt reply.  <You're welcome.> I hope you can clarify something for me. Are their good dissolved solids and bad dissolved solids? <Yep.> I was assuming that my goal in buying the RO/DI unit would be to achieve 0 TDS. So am I to understand that the RODI unit removes all TDS's both "good" and "bad", and that I need to replenish the "good" TDS that the RODI unit removed?  <The RO/DI units are non-selective in removing TDS, what you have is pure water.  Adjust the alkalinity and pH before adding the salt mix.  Now you have pure saltwater void of all contaminants, dissolved organics, etc.> Thanks again!  <You're welcome.  James (Salty Dog)> Wayne

Filtration/RODI System  3/20/06 Hello everyone! <Hello Dena> Question. I bought an RODI system for my water changes about 5 months ago. I had decided to start filling up my 5 gallon household bottles with it instead of going to the store to fill them up with RO. I have since been told that it is unhealthy for human consumption due to lack of the normal added stuff we have in our tap water. Is this true? I have been drinking over 120 oz a day for quite a while now.  Should I stop and continue to make the usual treks to the store like I used to? (getting the RODI filter has made me lazy) Thanks ahead of time for any info you may have.  <Dena, RODI water is the purest form of water I know of.  Out of your tap the water contains chlorine and fluoride.  The bottled water craze (Aquafina, etc.) contains none of these elements and a gazillion are sold daily, so you be the judge.  James (Salty Dog)> Dena   

Re: RODI water consumption   3/21/06 You know, that made a lot of sense to me too! I figured if it's good for my wet critters, it's good for me. So I have been drinking it.  However I ran across this article and thought I would pass it along. I am sure that of all of us marine tank keepers, I am not the only one taking advantage of the filters we originally bought for our fined friends and are filling up our 5 gallon drinking water bottles to save time and money. I have found several sites saying that distilled and deionized water is potentially dangerous for human consumption.  <I'd be more cautious about eating green beans out of a can.  Did you ever read the label on such...many, many chemicals in that can.> Here is one such link. You may find it interesting as will others on your wonder site. http://chetday.com/distilledwater.htm As always, thanks so much for your time and quick response.  You guys are great!  <And thank you for the link.  James (Salty Dog)> Dena

Re: RODI water consumption  03-21-06 Canned Green Beans, Urgggg. Only fresh or frozen for me. <I also.  My daughter buys this stuff in a can, thinks it's safe if it is canned.  Silly girl.> I think more to the point of all the articles I've found on the subject it is not all the crap that is added to our drinking water. On the contrary, with RODI it is all the valuable minerals and such that are being filtered out of the water that our bodies need. <I'd rather take vitamin supplements.> Not to mention, have you ever left even the smallest amount of your RODI water in the bottom of your Rubbermaid container for long periods of time. You will notice as I did that the bottom of the container begins to get rough. The water will actually eat the plastic! It will also eat through metals. Just a thought others may want to look into. I will do more research, but for now I think that I will purchase a separate RO system to put under my kitchen sink for my drinking water and keep the RODI for my beloved salty critters! Thanks for your time on this.  <You're welcome.  James (Salty Dog)> Dena

Low pH   3/16/06     I have a 72 gallon reef tank with the salinity at 1.024, the kH at 12dkh, the calcium at 400ppm, and my pH is at 7.8-8.0.  I've tried taking a bucket of the tank water and aerated it outside with a power head on the bottom pushing the water up, did not help, I talked to different LFS and it does not make sense to them.  I tested my water when I make it and is has the same pH of 7.8-8.0 as my tank. <Mmm, could be your salt brand/mix... this pH is not terribly low though...>     I have a SpectraPure 4 stage RO/DI unit that I run my water through, I aerate it for 24hrs. and the pH is at 6.9-7.2.  I add a 1/2 tsp. of Kent dKH buffer.  I let is aerate for another 24-48hrs with the power head on the bottom of the bucket, my pH is then at 8.3-8.5.  I have a bucket of water that is just buffered  for top off and one that I add salt to.  When I add the salt ( I've tried Oceanic, Oceanpure, and Instant ocean ) <The last is best/better> to the water the pH drops from the 8.3-8.5 down to 7.8-8.0 instantly and stays there, even 48hrs. later, I buffered the salt mixed water after 48hrs. up to 12dkh even tried up to 14dkh, after 24hrs the pH is back at 7.8-8.0. <Mmm, might be your "tester"...>      I have thoroughly read through the other situations posted on your site and could not locate a situation like this. If you have any suggestions please let me know, which I will greatly appreciate. Your site is an excellent site with a huge amount of information that has been very helpful to me in learning the hobby as my setup is going on 2yrs. old. All my fish and corals look healthy which is the main thing. <Well, there are other chemical prep.s you could avail yourself of... but if it were me, my system, I would first, check your checker... with another pH test kit/device, and not be overly concerned re the measures you list. Rest assured, many aquaculture and public aquarium settings have far lower values. Bob Fenner> Buffering RO Water   3/16/06 Hi guys. <<and Gals>> I looked on your great site (and even in desperation resorted to others how dare me) <<G>> for two hours and couldn't find a definitive answer so I have to bother you with a question which I am thanking you in advance for answering. <<No bother friend>> I recently went with an RO unit because my well water is "sub par" <<Not uncommon>> and now my pH in my reef tank has dropped from a steady  8.2 / 8.3 to 7.8. <<Not the "well's" fault, can happen on "city" water too...generally an issue with tank maintenance/husbandry.>> Now I have not been buffering my make up water (1/2 to 1 gal per day) <<Well there ya go <grin>.>> because I read that in my hundred gallons it should not make that much of a difference but I am now thinking it does and I missed something somewhere. <<Mmm, probably not a direct result of the top-off water alone...unless you have sufficient "buffering" compounds available (substrate/live rock/water changes/supplements) to the tank on a daily basis the pH will naturally become depressed.>> I do aerate and heat the RO water for several days however my question is about buffering it. <<Ok>> Everyone seems to rave about the SeaChem buffering product however call me slow but I would just like to use Kalkwasser as I have read that will work.  I also read baking soda works too. <<Indeed...I use the Seachem Reef Buffer myself for buffering my water for my salt mix, though I cut this 3to1 with baking soda to reduce the amount of borate added...and to save a penny or two.  I use Kalkwasser to buffer my top-off, through the use of a Kalkwasser reactor and an auto top-off system.>> Now my question.  I could find no where as to how much Kalk and/or baking soda or what the procedure is.  I am sure I missed it but I gave her a good go trying to find the answer.  I do not want to foul this up as I have read of the deadly Kalk Overdose Snowstorm and want to avoid that at all costs.  So......do you add the Kalk to the aerated heated RO water till you get the PH to level you want and then dump in as the make up water or does it still need to be dripped slowly.  Or is that even the procedure?  What about the baking soda?  How much per gallon?  Or should I just get with the program and use the SeaChem product. <<I think some experimentation is in order on your part here.  For buffering with Kalkwasser, a 1/4 teaspoon per gallon is a good starting point.  Any result with a pH of 9 or less should be fine considering you are adding 1% or less of the tank's volume.  For buffering with baking soda, start with a teaspoon per gallon and adjust as necessary.  I would aerate the water for 24 hrs. after adding the baking soda before checking pH to blow off the carbon dioxide present in the baking soda.  Or...f you decide this is all too much hassle, just follow the directions on the Seachem product.>> I would love to make my contribution by helping you guys answering e-mails for all the help you have given me but I don't think I am there yet.  Thanks again and you guys rock for your dedication to this hobby and answering these questions. <<I am pleased to be a part of it all.>> John <<Regards, EricR>> Buffering RO/DI water  - 03/11/2006 Hi there! <Hello> I try not to write until I spend a few days researching my question and come up empty.  Well, I'm empty!!  :-) I recently purchased a RO/DI unit and TDS meter.  The water is registering 0.00 on the meter which I am sure is what it should be. <Yes>   When I make up my salt water for changes, it's ph is 8.2.  I have another 5 gal bucket for top off water (tank is only 30).  I use Seachem's Marine Buffer to prepare the water for top off.  After the pure water is in the bucket I put in ¼ teaspoon of the marine buffer (as per directions after some division) and aerate it for 12-24 hrs.  When I check the ph, it is 9.5ish.  I have tried taking some water out and adding more RO/DI water, but it doesn't come down more than a point or 2 after changing over ½ the water in the bucket.  How bad is this for my tank? <If only a small percentage of total volume (less than ten-fifteen or so), not likely a big deal> I really needed to get the specific gravity down, <Easy enough to do...> so I didn't have time to play chemist anymore.  The bottle of marine buffer says that it will not go over 8.3 even if accidentally overdosed, but I have proven this wrong.  Or does it mean that when it is put in the salt water it will adjust itself and the tank to 8.3? <Should be closer, yes> I am really confused.  Please help. Thanks, Donna <Over time, with aeration especially the buffered RO should be closer to 8.2... best to store for a week or more before using. Bob Fenner> Water Quality/Marine   3/10/06 Hi everybody,<Hello Rad.> Just after a little reassurance about the cloudy water in my new tank. Had saltwater from RO/DI with instant ocean (mixed in tank) circulating for almost a fortnight (trying to deal with microbubbles issue) - no living matter in yet, I plan to add live rock soon.  My water is really cloudy (opaque & white) & shows no sign of clearing.  Is this normal or cause for concern? Should I ditch the water & start again? or am I safe to add LR?<I believe your problem stems from excess CO2 in the RO water.  Do aerate the freshwater 24 hours before adding salt.  This will rid the water of any CO2.  The CO2 in the water is forming carbonates and causing what you are seeing.  A disturbance of the sand bottom (if using) will cloud water also.> Thanks<You're welcome.  James (Salty Dog)>     Rad 03/06/06 - RO water I would appreciate it if you could give me a little advice. I have a 40 (US) Gallon FOWLR tank. When I set the tank up, a few months ago, I used tap water with additives (chlorine remover etc). I ran the tank for three days and added salt, sand and live rock. Since then I have been using a "Brita" filtered water for weekly water changes. I aerate and heat the water to 27 deg before adding the salt, when I get the specific gravity at mid range (about 1.023) I always achieve a ph of 8.4. My tank always maintains a ph of 8.3 and when I use the filtered water for top up I always maintain a specific gravity of 1.023. One basic problem I have is that I am British and living in Japan. Therefore the support I can get from my LFS is relatively poor, as my Japanese is not so good. I will shortly travel to Europe and I intend to order a RO system. Would you please tell me if I understand this correctly. When I use RO water I need to add something like Seachem marine buffer to 8.3 before adding the salt, then is this assumption correct? When I add the salt and get the correct specific gravity the water is safe to use?  <I would just use the RO water direct and test your PH.  The salt should buffer the water already. If you require more then add it but I think you will be ok with just your salt. Many thanks to your website that has already stopped me making many mistakes. p.s. I have ordered the conscientious marine aquarist and will pick it up at the same time. (hopefully I can stop asking basic questions when I finally get my hands on it). thanks in advance Steve  < THANK YOU ERICS > 03/01/2006 RO/DI Hey Crew!!  Great site.  Very informative!  <<Thank you very very much :) >> Here is my question:  I have been using Aquarium Pharm TWP to make my water for top-off and salt mix.  Finally got tired of spending the money on cartridges and decided to finally get a RO/DI unit.  I have been reading your FAQs about this and have found a few differences of opinions.  Please help clarify for me. When I make the water the pure water goes into (2)  5gal Home Depot buckets (I only have a 30gal tank, don't need tons of water).  The buckets are covered tightly and set aside till I need them.  When I do top-offs, I aerate, heat and buffer one of the buckets for 12hrs or so then check levels and put it in the tank then reseal the rest.  When I need to add more, I again aerate and heat and check the ph and buffer if needed use what I need and seal the rest. When I do water changes, I take 4gal from the unused bucket into a separate mixing bucket throw in a powerhead with aeration and a heater and wait for the temperature to get to the tanks temp.  Then I throw in my salt (Crystal Sea) and continue to aerate and maintain temp for about 12hrs. Check levels and use.  If I don't use it all, I add more RO/DI water, aerate and heat then add more salt. I just don't know if I am handling the RO/DI water correctly.  Can I just keep it sealed in buckets till I need it?  It shouldn't be there more than a week or 2 total, and that is with some use for top-offs and such.  Am I missing a step?  << Sounds good to me.  I have a garbage can with a float valve that I like to use for topping my tank off.  One thing to keep in mind though is that this is stagnant water and if it sits too long it could begin to grow bacteria and smell.  Make sure to clean the containers well when you have a chance and check them before using them.  Hope this helps. Eric S >> Please advise. Thanks, Donna Low pH, high calcium and KH. - III   2/26/06 Bob (and Crew), <<Hi Mike!>> Thank you for your prompt response.  What should I use to bring the pH up in my new water? <<There are many pH buffers available at fish stores.>> I'm not concerned about a snowstorm in my new water so much as I am in the tank itself. <<This is why it's best to mix, buffer and heat your replacement water before adding it to your tank.>> As a rule, is there a supplement I should be adding to my RO/DI water in addition to the salt mix in order to help with the pH or just as a general rule? <<Buffer to desired pH prior to adding to your tank. All posted on WWM.>> Thanks, Mike <<Glad to help.  Lisa.>>

RO/DI water... necessary?   2/23/06 Hi, its Luke, we met at the PSAS lecture Hi, its Luke. <Hey Luke! Ah, yes, the "Dead Sea" fellow, sans water changes> We went to outback together with some other folks after the excellent lecture you gave.   I am the young guy that doesn't water change or skim, Chaeto filtration only with precautions taken to avoid any NNR from occurring. anyways... I made a new thread regarding some points from your lecture, and quite as I suspected, people simply don't believe/understand that you encouraged us to use tap water in our aquariums. <I do... and do> Lots of these guys are the fussy-dussys who keep things exactly status-quo with the current trend... (in other words, the sort of folks who will never make a difference in the hobby) <Mmm, don't be so fast to judge here> Anyways, its a medium sized (10,000 members) forum that's really quite pleasant and laid back.  If you wouldn't mind spending the time to make/post a paragraph regarding your thoughts on the importance of RoDi, I know myself and a few thousand other people would really benefit from it. thanks a bunch bob -Luke <Where? BobF> I don't know if i remembered to give you the link in my last email, but here it is if I forgot. http://www.reeffrontiers.com/forums/showthread.php?t=13177 <Oh, yes... MikeO's work. Don't have time/interest in more work on the Net Luke... you're welcome to post/quote my input... BobF>

Buffering RO/DI   2/14/06 Hello Crew, <Tom> There are a lot of answers on your site that suggest one should age, then buffer, RO/DI water before using it to make Instant Ocean and presumably before adding it as top-off water. <Yes, this routine is best> What I am not sure about is if this applies when using a two-part alkalinity/calcium supplement (C-Balance). <Mmm, best to add just one of these in the make-up water, and drip/place the other in the main tank...> Specifically, this is my current situation: Generally, I age, but do not buffer, RO/DI water that I use to make Instant Ocean and to top-off for evaporation loss.  However, my alkalinity had been low for a while (6.0-7.0 dKH), so for a couple weeks now I have been using a teaspoon of Seachem Reef Carbonate per gallon of water used to top-off. <A good product, technique> As of this morning, I have alkalinity of 8.0-8.3 dKH and calcium of 330-350 ppm (Salifert tests).  That looks pretty well balanced, though both numbers are near the low ends of what Anthony considers optimal (8-12 dKH and 350-425 ppm). <Yes> At this point, should I just use the two-part alkalinity/calcium supplement daily, and not buffer my RO/DI water?  Or would you recommend buffering? Thanks, Tom <I would try the buffering for now... along with the abundant biomineral and alkalinity in your salt mix brand (IO) this ought to get you about where you want to go, be. Bob Fenner> Reverse Osmosis Wastewater   1/20/06 Hello, <Hello Nick> After many hours of online research on the subject (WWM is always the first place I check) I was unable to find the answer to my specific question regarding Reverse Osmosis "wastewater".  It is widely known that these units waste anywhere from 4:1 to 10:1gallons in their quest for purity - my question is can the wastewater be routed back through the filter repeatedly to maximize the pure water output? <Think about it. if it was waste once, it will be waste again.  In doing this you will be gradually adding to the waste water> I would like to set up a system which would include two holding tanks (one containing tap water and one to hold the pure output water) with my Coralife  4 stage RO/DI unit in the middle (wastewater would be re-routed back into the tap water holding tank).  Aside from possible shortening the life of cartridges/membranes are there any pitfalls to setting up this system? <Really don't see any benefit in doing such.  Save the waste water for use in watering plants, washing the dog, etc.> If it matters, I am using chlorinated city water of fairly high quality (aside from the high level of phosphates/silicates). Thanks in advance! <You're welcome.  James (Salty Dog)> -Nick Re: "melting" corals 12-12-05 follow-up to the follow-up... processing possibly contaminated RO   1/19/06 Hello, Bob.  My priors are below for review of my system.  Have now lost the torch coral, too.  Pachyclavularia and leather mushroom remain, and a plate that looks like it's struggling.  The fish are just fine.  I may have figured it out, but I'm not sure, and wanted your opinion.  I place some PolyFilter during my troubles to combat negative cnidarian interactions, and when I pulled it, it was blue.   <Yikes!> I've never medicated the tank, but I bought a copper test kit.... 0 in distilled water .15 mg/L in the tank .25 mg/L + in my RO water that I've been using (new filters a month ago) I noticed a very recent email on your site about copper in the source water, and you guys recommended RO, but I'm already doing that, and still with the copper. <Very strange> I started the tank with bottled water, not RO, so I'm wondering if after time and water changes over several months, copper accumulation may be the issue in spite of the RO I'm using now... <Could be... the blue color...> Does this make sense that the copper at those levels is killing off my livestock? <As stated, a possibility> If it does, how do I combat?  Does carbon pull out copper? <Yes... activated> Do you think it would be sufficient to continuously run carbon and/or PolyFilters, or do I need to convert to (expensive) bottled water for all my water changes and top-offs? Haven't lost hope, yet, but I'm getting there..... Tim <Processing your RO water in a container that hast activated carbon in a filter... should definitely do it. Bob Fenner>

RO/DI water    1/19/06 Hi,<Hello Linda> Thank you again for your prompt response to my questions.  I'm really liking your site! <Glad you do, very informative.>       You recommended RO/DI water & frequent water changes in a small [40 gal] reef tank instead of additives. <Depending on the inverts you keep, you may need to dose calcium, strontium, iodide, etc.>  I know what RO water is, but what is DI?  Can I get it in bottled water in stores like Wal-Mart where I now buy my distilled water? <DI is deionized water.  RO and DI perform the same task but DI purifies water using the principle of ion exchange to remove impurities and replace them with pure water.  In most cases RO serves as a well rounded filtration method that will remove the majority of the impurities, generally 88-94% pure.  If you couple this to a post DI unit the purity is 99.9%.>  Also, for a 40 gal tank, how often is frequent & how many gal to change. <Four gallons weekly will work well.> Presently, I "vacuum" & do about 10 to 12 gallons water change every 2 1/2 to 3 weeks. <Better to do the 10% (4 gallons) weekly.>     Also, are there any special foods to feed crabs, urchins & other small creatures other than the brine shrimp & MicroVert I fed my fish & coral? <This info is available on the Wet Web, do search/read.>     Sorry, one more question - I am having a hard time regulating my temperature in the tank even with a heater.  I am aiming for between 77 & 80, but don't always get that with my heater.  At night it goes down & in the day the temp goes up.  Sometimes it is a little more or less.  Is this OK? <Your lighting is more than likely causing the rising temp during the day.  I don't know what your nighttime temp is so I don't know if it is OK.  You really don't want the temp to vary more than five degrees during a 24 hour period.> Thank you again for your help. <You're welcome.> I am going to show your site to the 2 aquarium stores that I go to in my area. <Great.  James (Salty Dog)> Linda Campbell, beginner reef tank enthusiast

RO & Waste Water - 01/02/2006 I know that an RO filter is one of the most useful tools for this hobby. I currently have a 50GPD unit and of course it takes forever to fill up containers. My question is, if I upped the GPD to say a 125 would I save on my amount of waste water. <Umm...No. The process doesn't change, so you'll actually make more waste water as well.> I was told by some that I won't, and others have said yes I would. James <James, the RO production will still create the same ratio of waste water (I think around 3 gal. for every one). The waste water however doesn't have to be discarded. Find some good uses for it (water plants or some such). - Josh>

R.O. waste water question 01-19-06 Hello, <Aloha> Just one quick question about the brine or waste water from a R.O. unit. Can this waste water be filtered again with an additional DI cartridge and then fed back into the carbon block before it enter the membrane again? <It could, but you will destroy the DI cartridge. Brine has an extremely high TDS and the DI would try to remove all of those ions.> It just seems like a lot of waste water going down the drain. <You are correct.> I have been using a home made (Home Depot) design of a ceramic 5 micron sediment filter and 2 DI cartridges (the same ones used by Kent Marine) for almost 5 years with no waste water produced. According to my conductivity meter the water I get from my system is only about 0.02 micro-siemens and RO water from A Kent Marine Unit measured a level of 36.2 micro-siemens. May be I am missing something...Please Help... I am thinking about buying a RO unit for my reef because the cost of DI cartridges is pretty high. I now think that the money saved by not buying filters for my home made system will go down the drain anyway... <You are correct that there is a lot of waste water produced with an RO unit. You can actually figure you will have 3-4 gallons of waste for every 1 gallon of usable water. To recycle your waste water you could look into using it do the laundry, water the plants, etc.... If the volume of waste water still bothers you, you can look into rechargeable DI units. There are many great articles on DI units on the web. Here is a place to start: http://www.wetwebmedia.com/diunitfaqs.htm  Travis> thanks...Happy Reefing RO/DI not removing phosphate 11/25/05 Hi Guys, I am trying to figure out the origin of my problem. I recently purchased Pure-Flo II RO/DI Unit - 50 GPD TFC - 3 Canister and having troubles with it. So far I can only see that there is something wrong but I can't identify where exactly. So here what I have. Before attaching this unit to the water source I rinsed the carbon block for about 15 minutes under the stream of cold tap water in order to remove the trace of a phosphoric acid.  After that I attached the unit to the water source. My tap water has Phosphates reading of 0.5 ppm. I discarded first 15 gallons of water and then produced additional 5 gallons to make a partial water change in my tank. After I did the water change, ~ 10% of my tank volume, next day I observed the boom of assorted algae. The phosphate and silicate readings in the tank are 0(I am using Salifert test kits). But how I was surprised when I observed that they are not zero in the RO/DI water that I made. In fact the level of phosphates is the same as the one in the tap water.  Which made me think that the unit operates incorrectly or I am doing something wrong.  Thanks in Advance.  Alex   <I would contact the company for support on this issue, but in brief... as you obviously know, carbon blocks often contain residual phosphoric acid.  I would suggest testing a sample of water that has passed through the carbon, but not through the RO or DI.  I suspect that you will find that the phosphates are off the chart.  Under normal circumstances, RO/DI will adequately reduce phosphate, but when such high concentrations are present coming in, some is going to make it through.  You will most likely have to replace the carbon blocks with pre-rinsed ones to solve this issue.> Tank Info: 30G FOWLR, Remora Aqua C with MaxiJet, Lunarlite 2x65 PC/Actinic, MaxiJet 1200, Hagen power head 30, Fluval 204 (cleaned on daily basis), ~20 lb of LR, no fish no inverts but some kind of worms and insects that came probably with LR, still cycling. Water parameters: Ammonia 0.25 (used to be 0 last Friday), Nitrite 0, Nitrate 5, Phosphate 0, Silicate 0, Ph. 8.3,  Calcium 400.  <All sounds good!  Best Regards.  AdamC.>

RO/DI Investment 11/25/05 Happy Thanksgiving crew. <<Same to you Anthony.>>  Hope you're lucky not to be working today. I'm debating if I should invest $200 on a RO/DI. I have two 60 gal tanks. What I normally do and is no big hassle for me is to bring three 5 gal bottles to a reputable water store that makes RO with UV processing. My only concern are phosphate/silicate levels.  So what I do now is fill a 30 gal Rubbermaid with the purchased RO and use the Phosban reactor with Rowaphos which gets rid of the phosphate in less than a day. Would I get the same overall quality with this method compared to a RO/DI like Kent Marines' Maxima Hi-S? <<You would get higher quality with your own RO/DI system. You should expect TDS to be 0 from your own well maintained system.>>  I'm assuming that the RO machine at the water store is well maintained (no idea about micron sizes). <<Not necessarily a valid assumption.>>  They have an attached TDS meter which always reads under 5. In terms of my current cost.  I would need another reactor ($35), Rowaphos (500 ml - $30), and RO from the water store $1 per 5 gal. But I won't mind spending another $140 for my own RO/DI for the purest water and convenience. <<As long as the monetary investment is not an issue, you can't go wrong by having your own RO/DI unit. The DI cartridge will remove phosphates and silicates. Test your home water for total solids, phosphates and silicates. Invest in a TDS meter and monitor the output from your RO/DI system. Change the DI media when it is exhausted (you can buy refillable cartridges and resin on-line). You may still need to run the RowaPhos on your converted system because food can introduce phosphates but you won't need to run it on the RO/DI water as long as the TDS is 0.>>  I'm converting one of the 60g tanks into a reef and don't want any algae problems. I also bought a CPR hang on refuge which with the appropriate plants can reduce phosphates (by how much - I don't have a clue.) Thanks again, Anthony <<You're welcome. Good luck - Ted>>

Re: calcium deficiency   11/15/05 Thanks again. One more little (big) problem - my RO water has a PH of 8.9(!) <... unusual... I would aerate it for an hour and re-check> could I beg a moment of your time to precisely what I must do? ( I am a newbie at this- ) Your site is terrific- I just wish I had the excuse to sit reading for hours! Barbara <Do what I do, make one up. Bob Fenner> 

Re: calcium deficiency... RO storage  11/16/05 Hi Bob, Great, it worked. Thanks. But one more question to bore you with:- Can I store the RO water in its collection bucket for a few days prior to use/aeration, or should it be freshly RO ed? <Better by far to store, aerate> The pH in the tank has come down to 8.4 but the calcium is going no further up nor the KH down. <Takes time... go slow my friend> I am going to do a 10 gall water change with correct pH and Sea Chem salt. Am I right in so doing? <Look into another brand of salt... Perhaps an Instant Ocean product> and if so, how soon before another (how big) change? <Another week or two> Sorry to pester you but am getting such conflicting advice from the store. Thanks for your time Barbara <Seek to understand, demand the underlying logic, science of such (including my) "advice", stances... Important in the extreme to understand "what we're about"... before setting on a path... This is one of the most important "things" I know re this universe. Bob Fenner>

Re: Detritus/Algae/Cloudy Water in a Reef Tank 10/30/05 Thank you for answering back so fast.  <No trouble.> We do siphon waste matters and whatnot when we do the water changes.  <That's good to hear.>  We will try increasing the water flow.  <Can't hurt.> The water we use for changes is RO water we get from our LFS. Could it be his filter? <Maybe the filter media in an RO/DI unit should be changed annually for best results, if his are old, it could be the same as using tap water.> Shrina. <Adam J.> 

Drinking Like A Fish - 10/27/2005 Hi.... <Hello.> Problem.... My wife has had an unusual thirst for several years while drinking our well water; a gallon or more a day. <That's a lot of water - though, admittedly, I often drink a couple of liters of filtered water daily. I don't think this is unheard of. Best to check with a doctor, though, if you think it's something unusual.> One day, while at our daughter's place, she brought home a gallon jug of her city water. The consumption went down to less than half a gallon.  <Not sure what the significance is here.... Uh, real quick, just wanted to mention to you that we deal with fish on this site more than anything else - none of us (save for one Crewmember) are physicians.... best to check with your doctor if you are concerned about anything health-related.> I am considering an RO system. Do you agree that this will solve her problem by removing the silicate level?  <I don't know anything about solving her problem, but an RO system should remove silicate.> Will the Ultimate V Drinking Water System, which is a four stage system, do the trick? <I'm not familiar with this system. I imagine it would remove silicate. Best to contact the manufacturer as well, and ask them.> Thanks for any light you may shed on this unique situation. <Glad to be of service.> Floyd <Wishing you well, -Sabrina>

DIY RO Unit - 10/26/05 Hi all, thanks for such a wonderful site! You have no idea how much help I get from y'all! <<Howdy, glad you like it.>> I talked to another aquarist about finding a cheaper RO unit and he recommended I make my own. <<ok>><<<RMF would not do this, nor recommend it... too much likelihood of gear/plumbing failure... water damage>>> He said to put the cartridges (sediment and carbon) in 2.5" PVC plumbed with 3/8" tubing, sediment first and carbon later, and then have a third such cylinder filled with Poly-Bio-Marine's Poly-filter pads before going to the aquarium. <<Hmm...unless you can rig this as such to "force" the water through the sediment filter and carbon block the water will take the path of least resistance and go "around" the filters with much filtering taking place (The manufactured housings are designed to prevent this happening.). Though the last stage filled with (cut-up) Poly-Filter will likely work fine.>> He also said that you could actually plumb in the RO membrane the same way if you want to spring the $60 for it (price at Home Depot). He 'says' that this is just as effective as RO but half the expense and no wastewater. What is your opinion? <<I disagree...I would spend the ten or twelve dollars for a proper RO housing. The membrane requires much water pressure (avg. 60 psi) to be effective. Unless you have a plan/skill to build the housing I don't think DIY is the way for most folks to go. On the other hand, the cheaper units (sediment/carbon prefilter with RO unit) sold by HD and such would be quite satisfactory. Tis up to you, but without more info and a better understanding of this DIY unit a can't recommend it.>> The materials to connect from my kitchen sink to both aquariums (150 FW 3' away and 55gal Reef 25 feet away and in the basement) before the cartridges cost about $60. <<I don't recommend connecting RO units to fill directly to an aquarium. Water for the reef tank needs to be aerated 24 hrs. min....and buffered for sure.>> The cartridges will cost about $35. Thanks again for all your help. Branon. <<Regards, EricR>>

Re: Alternate 'RO' Filter? - 10/27/05 Eric, thanks for the response. <<Anytime Branon>> I'm not actually planning on using the RO filter. I may run it through a DI eventually, but am undecided as I would like to keep some of the buffering already in the tap water while removing the copper, phosphates, chlorine, etc. <<Mmm...I believe in the benefits of RO (better yet, RO and DI), and the effluent is easily buffered with simple baking soda.>> The water will be forced through the sediment and carbon because they fit very snuggly into the PVC and the center throughway of each will be blocked by a 'rigged' nylon washer. <<Ah, then there is a plan...good. But do be aware, "snugly" will not be enough as the filters start to clog. Better to seal with some type of O-ring design if possible.>> The filtered water will run into a reservoir that feeds into a Nilsen reactor for the reef <<Excellent!>>...I'm not sure how to automate the same for the 150gal freshwater tank top off- suggestions would be appreciated. <<If you're not using RO there is probably little concern with a direct feed so you could simply set up top-off from an aerated reservoir filled from the filter unit. But, depending on what you are keeping, the freshwater may need buffering as well.>> Oh, another question related to this...do you think this will reduce the pH of the source water significantly, sans DI or RO? <<If you're only using the sediment/carbon/Poly-Filter rig you describe I doubt there will be much impact on pH.>> Thanks again. Branon <<Always welcome, EricR>>

RO water for Kalkwasser auto-top-off - 10/17/05 Hi There, <<Hello>> I have perused the FAQs but have not seen a direct yes or no as to whether RO water can be used to automatically refill a kalkstirrer without pre-aerating or buffering. I am sure I have seen schematics on manufacturers websites showing an RO plumbed directly to a kalkstirrer. <<It sure can be added straight in.>> Thanks for your help David <<TravisM>> 

About top-off water 10/10/05 Hi, My 55 gallon aquarium is not housing any corals, nor fish at this time, as it is fairly new. The ph, calcium, alk and other parameters are fine. My question is do I use any sort of supplement in the DI water I use? I have fans that cause evaporation at a rapid level...every two days or so. I use SeaChem products only in water changes when I have corals, etc. utilizing the calcium. But for now, do I just add the DI water as is?  Thank you, Eddie <Eddie, you might want to add an alkalinity booster (Reef Builder, etc) in your DI water to elevate the dKH to 8-12. James (Salty Dog)> 

Water treatment  9/27/05 Hi guys; <Hello Ron> I was concerned about using my tap water for my marine tanks. I have a spectra pure R.O. unit but have not used it for about one year, <mmmm membrane may be dried out by now.> My question is should I start using it, <You can try it, see if it still works.> it's a little time consuming and do not want to run up a big water bill on my landlord. Also I do have a Eheim pro canister filter that I just unhooked from one of my tanks, a f/o live rock tank could I use this filter to treat and prepare tank water what's your suggestion? Thanks, Ron. <Run some test on your tap water, ph, nitrate, phosphate, may not be necessary to RO the water.  Might want to take a sample down to the local pure water store and have a TDS reading done.  I really doubt your water bill is going to skyrocket from using the RO system.  Difficult to rig up a filter that is going to produce 98% pure water.  James (Salty Dog)> Panic Time...Nope - 09/25/05 Greetings Crew: <<Howdy>> I would be very thankful for your help with a water mixing question... <<I shall try...>> Log 9/24/05: Mixed my first batch of water today in preparation for bringing home live rock next Saturday.  The RO water tested pH 6.0 (electric meter and test kit agree).  The Total Alkalinity tested 16ppm (yes 0.9dKH, by LaMotte titration).  By reading information on http://www.wetwebmedia.com/ I learned to adjust Total Alkalinity before mixing salt. <<yep>> I read the instructions on the SeaChem buffer and calculated that 25 level teaspoons would raise pH from 6.0 to 8.1 in 50 gallons (it said use a level teaspoon to raise pH by 0.1 in 40 gallons of water).  But, I calculated that only 8 teaspoons would raise Total Alkalinity to 125ppm (about 7 dKH).  So, I put in the lesser amount. <<wise>> Result after one hour of circulation:  The Total Alkalinity tested 128ppm, right on the money, and the pH was 8.2.  So, I then put in the calculated amount of Instant Ocean salt, and got specific gravity of 1.024.  I thought all was well.  BUT, the pH went to 8.6 after the addition of the salt <<Not a problem in my opinion.>>, and the Total Alkalinity went off the chart at 280ppm (15.6 dKH).  OH NO, Panic.  So, I dumped another 7 ½ gallons of RO water into the tank. <<I would have let this aerate for a day/couple days first.>> Result after 15 minutes: The pH came down only to 8.5, and the Total Alkalinity dropped to 240ppm (13.6 dKH).  But, the S.G. dropped down to 1.022. <<Yes...dilution...>> I fly out to Florida tomorrow, and won't be back until the live rock comes on the plane with me (I know, bad plan).  I would really really appreciate your help in what to do at this point to get things right - I hate the idea of killing hundreds of dollars of live rock, and worse yet the idea of trying to get my wife to mix salt over the phone J . <<Your alkalinity is not that bad, on the high end yes, but not that bad, and your pH is actually where I like to see it.  I think you will be just fine...would like to see that salinity increased a bit though...and next time, give the water a few days to a week to "season" with constant aeration.  I use IO salt extensively and always buffer to 8.4/8.5 before mixing.>> Thank you as always, Brad in Basalt <<Welcome...EricR in Columbia>>

RO Water Buffer Question - 09/22/05 WWM crew, I think I may have missed something in the articles and FAQs.  After aerating my RO water for 12-24 hours, to what pH should I buffer before I add the salt mix (Instant Ocean)? <<I always strive to buffer my RO to a pH of 8.3 (plus or minus .1)>> Should I buffer to a pH of 7.0 and let the salt mix raise the pH to desired value (some one in the FAQ was advised to do so)? <<Can do...though this robs buffering capacity from your newly mixed seawater.>> Or should I buffer to 8.3? <<Is what I would do.>> My first time preparing for a water change, I added too much buffer -- raised the pH to 9!  Had to throw away most of the RO water. I have Seachem Reef buffer 8.3.  In the FAQs I read that you should "add enough buffer to get to say 60-100ppm hardness".  I can't measure for hardness right now, which is why I'm wondering about pH. <<No worries mate, use of the Seachem product and measuring pH will suffice...just be sure to follow the manufacturer's instructions.>> Thanks KC <<Regards, EricR>> Follow-up To RO Water Buffer Question - 10/01/05 WWM Crew, I have a follow-up to my previous buffer question: <<ok>> For some reason I can't maintain a pH higher than 8.0-8.1 in my make up water.  I've been following the Seachem 8.3 buffer instructions, but the pH raises, then falls to the aforementioned levels. <<Use the instructions on the product as a guideline...might need to add a bit more.>> The water has been aerating for a few days, and this evening I came home from work, and there's white powdery stuff on the wires and probes of the thermometer and the pH and salinity meters. It doesn't seem like salt (based on a possibly ill-advised taste test of a very small amount). <<Hee!>> Additionally, it seems like something (salt or buffer product?) is undissolved in the water.  Before I left for work today, the water was very clear, and this white stuff didn't exist.  Any idea why I can't maintain a higher pH? <<The "white stuff" is some of the buffer precipitating out of solution.  Some precipitation is normal and to be expected, but I wonder if you're maybe adding "too much" buffer at one time.  This could cause excess precipitation which in turn would cause the drop in your pH.  You might try backing off on the buffer by about a third, and then slowly add more to achieve the desired pH.>> (I'll be keeping a snowflake eel, a lionfish, and a Picasso trigger.  If I can't solve the pH thing, I'm only concerned about any future trigger; in CMA, Bob mentions that eels can survive in a ph of 8.0, but triggers require a higher pH of 8.2-8.4.) What is this white stuff, and what caused it?  Too much buffer product? <<Possibly. as previously stated.>> Do I need to throw out this water and create a new batch of make up water? <<Not at all.  Just try adding a "small" amount of buffer and see if the pH will come back up.  If I may make a suggestion... I love the Seachem product, and use it myself, but I "cut" it with baking soda on a two to one basis (two-parts baking soda to one-part Reef Buffer).  With this mixture I find I can easily buffer my RO water to a pH of 8.5 (will take some experimentation on your part to discover the correct amount for your water volume).>> If I need to start over, what are the minimum number of hours I need to aerate the RO water, aerate after adding buffer, and aerate after adding salt mix? <<Aerate a minimum of 24 hrs. PRIOR to adding buffer to dissipate CO2...then aerate continuously until use.>> I remember in the FAQ that a Crew member mentioned that the entire process can take only 24hrs. <<Mmm...before adding buffer/salt yes...bit tis best to let the mixed salt water "age" for a few days before use.>> Thanks in advance, KC <<Regards, EricR>> Using RO water with a twist  9/19.5/05 Greetings Great Sages: <Hello Brad> I have been building a custom 130 gal bow-front, stand and refugium for 8 months now.  Almost done & getting nervous.  I have read many questions about using RO water for marine aquaria on your site, thank you.  My RO water comes out of the tap at pH 5.8 ! <I'd be thinking it would be in the 7.0 area out of an RO unit.  Wonder what the ph of the tap water is.>  I know you recommend using a buffer to adjust alkalinity to that of NSW before mixing salt.  But, considering my low pH, what do you think about circulating the RO water through Calcium Carbonate to pick up calcium (instead of using CO2 as the source of acid in a calcium reactor)??  Any last words on using RO for mixing water would be appreciated as I pick up my first batch of Florida Live rock in two weeks. <When the salt, with all of its carbonates is added, the alk would go up and if you ran the water through calcium carbonate then precipitation would almost definitely occur dropping ph along with the carbonate level.  Just my opinion.  I'd try mixing up a gallon of sea water and experiment.  I'd be interested in the results.  James (Salty Dog)> Thank you sincerely for all the hard work you do, and the great service you perform. <You're welcome> Brad

Re: Using RO water with a twist  9/19.5/05 Hi James, Thanks for the reply.  The pH of the softened tap water is 7.2 .  This measurement, and the RO water measurement of 5.8 pH were made using a Oakton pHTestr TM calibrated with a two point calibration.  At work, we have a large industrial RO system that produces 3000 gallons a day.  That RO water also comes out acidic (6.4pH).  We presume this is due to dissolved atmospheric carbon dioxide forming carbonic acid, but we really don't know. Good idea on running an experiment on dissolving calcium carbonate.  I will report on the experiment as soon as I find time to do it. <Thanks.  Brad, one way to raise your ph is to aerate your fresh water 24 hours before adding the salt.  This will remove the CO2 and should give you a higher ph and dKH reading.  James (Salty Dog)> Brad RO Water Follow up 9/8/05 Did you guys forget to answer? <Nope!  Please see Sabrina's reply imbedded below.  Also, let me add that they carbon prefilter for your RO is meant to remove chlorine.  This filter should be changed as recommended since chlorine is harmful to the actual RO membrane.  AdamC.> RO and Chlorine - 09/07/2005 I have a question about RO water, I was told it could still have chlorine in it and should be treated with ultimate or other water conditioner. Is this true? <I do believe RO filtration removes chlorine....  Your best option is to purchase a chlorine test kit and check your filtered water.  Should be safe.  Wishing you well,  -Sabrina>

Storing Water for Water Changes (8-30-05) Hi Crew, Hi there, you have Leslie here this morning.> I really appreciate all your help. You make keeping a marine tank so much easier. <You're most welcome and thank you for the kind words. We are glad to help.> A quick question please. <Sure> I am going on holiday for a couple of weeks and my son (who has previously kept his own tank) will be taking care of my fish tank while I'm away. I am very particular about water changes, aerating the new water for a couple of days before adding it to the tank and just know that he won't have the same patience. Could I mix the water for the change he will have to do, and leave it aerating for about 10 days ready for the water change or is that too long for the water to stand? <Nope, that should be absolutely fine> Does my question make sense? <Yup, it certainly does.> Thanks, SharonJ <Your welcome and have a great holiday, Leslie>

RO/DI unit 8/29/05 Hello, <Hi there> I was wondering if I could have some advice on a water purification unit.  What name brand would you recommend?  I'm looking for a ro di unit 24 to 50 gpd.  I was leaning towards the Kent marine brand but I also seen a cheaper one from ESU (Coralife).  Any recommendation would be appreciated. Thank You, Andy <The cheapest units... like at large hardware stores, are what I generally endorse... the pet-fish ones are not made by the companies that put their stickers/labels on them... Bob Fenner>

Buffering RO/DI Water - 08/28/05 Hi guys. I am hoping you can give me some advise on what to do. <<I shall try.>> I am new to the hobby and have been playing and testing pH levels. I have 2 test kits and a pH Pen. <<Not a bad idea to have several methods of testing/reference.  Though I find I tend to depend on my electronic meters for daily "quick" checks.>> When I first make RO/DI water and test the pH it bottoms out on the pH test chart meaning it is below 7.4.  pH pen shoes just below 7. <<as expected>> Next I add Instant Ocean Salt and retest the pH, 8.2 on all tests. Great. <<yes>> Next I add a buffer (Seachem 8.3) according to the directions (1 teaspoon per 20 gallons).  When I test the pH it is off the charts and pH pen shows 9.8??  Then I tried, RO/DI water, Instant Ocean and some Kalk with no buffer, 9.8 again.  What am I missing here? Should I be adding way smaller amounts than the directions? <<Maybe...think of the directions as a guideline/starting point.  Perfectly fine to make adjustments based on your test results.  But I think the problem here is your methodology...I would prefer/recommend you buffer the RO/DI water BEFORE adding the salt mix.  The purpose of buffering the RO/DI water is to raise pH/alkalinity so as not to deplete elements from the salt mix.  Even though your salt mixes with the RO/DI water at a pH of 8.2, I suspect it is a "weak" reading that will/does drop very rapidly once added to the tank.  You may still need to adjust the quantity of buffer added, but try buffering first, then adding the salt mix and see what happens.  A slightly elevated pH over what you are getting with the salt mix alone (8.2)is fine, even preferred, in my opinion (up to 8.6). Right now, I am sticking with plain old Instant Ocean and RO/DI until I can figure this out.  My tank is at 7.9 to 8.2 depending what test kit I am using.  Any help is greatly appreciated as I am lost! <<No need to fret my friend, this matter is easily resolved by mere testing/adjusting of components as needed.  Do try my suggestion, and have a read through our tap water filtration FAQs ( http://www.wetwebmedia.com/rofaqs.htm) to find more info/opinions on buffering/mixing salt with RO water.  Regards, EricR>>

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