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FAQs on Tapwater Filtration: Reverse Osmosis, Deionized, Distilled Water Post Treatment

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

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

RO System Hi, Robert. I want to buy a RO system since my tap water has a high silicate content. Do I need to add supplements to the water before adding it to the tank? <Yes, please see here http://www.wetwebmedia.com/rofaqs.htm regarding treating purified water.> Thank you, Bernd <You are welcome. -Steven Pro>

freshwater tank; RO use... not exclusively       1/28/17
hi how are you I have a salt tank and want to set up a freshwater tank with plants. I have a ro/di filter can I use ro water to set it up
<Mmm; no; need to have "some" mineral content... depending on the types of life you intend to keep. Plants; tetras, African cichlids... they all have particular needs, ranges here. You can search on the Net, in books re; and build your livestock assortment around your tap water quality or use the RO mixed in to dilute if needed>
I heard that ro water is not good for freshwater, but figured since I have a ro/di I would use it but I think I read somewhere that it take's all the vital nutrients / metals out needed for freshwater. what do you think .
please and thank you
Val Sammut
Toronto. Canada
<Welcome. Bob Fenner, Lautoka, Fiji presently>

Salt Mix and Low pH   9/17/10
Hello, and thanks for all the great information available through this web site.
<Hello Rob, and you are welcome.>
My question is specific to the Reef Crystal salt mix and my pH. I make my own RODI and the pH is 9.0 before I mix in the salt.
<The pH of highly purified or RO water cannot be measured accurately by test kits, or by pH meters. One of the reasons for this is that highly purified water has very little buffering capacity, so its pH can easily change.
A well functioning RO unit should produce water with a pH somewhere near 7.0.>
After the mix, it drops to 7.5.
<Sounds correct as there are little to no buffers present in RO water and the buffers in the salt mix are quickly being depleted.>
I have been using this for about 18 months with no problems, but would like to improve my water quality to optimum so I can progress with corals. I see that a pH of 8 - 8.2 would be best. Why would the pH be dropping, and should I be correcting before adding to the tank. If I should correct, what would be the best buffer?
<Yes, I would buffer/adjust the pH to 8.0 - 8.2. And before doing so, allow at least 24 hours after you mix the salt and take a pH reading. As far as buffers go, I personally use Seachem's Marine Buffer, works very well.>
Thanks for any help you can supply.
<You're welcome. James (Salty Dog)>

Pre-buffering RO Water w/B-Ionic 08/30/10
Dear Crew,
<<Hiya Jillian>>
Thanks so much for your wonderful wisdom!
<<We are happy to assist>>
Just a quick question today.
Is it ok to pre-buffer RO water with the alkalinity part of B-ionic instead of with a powdered buffer such as Seachem's Reef Buffer?
<<Sure Is all still Carbonate/Bicarbonate ions>>
I have found myself with a bit more of the alkalinity part of the solution left over for my reef tank and wanted to use it up.
<<Shouldnt be a problem>>
I know that the 2 part calcium products are designed for use in saltwater and I have never read anything about applying them to freshwater before adding the salt mix.
<<Actuallythe concentrated versions (gallon jugs, et al) are meant to be diluted with RO water before useand if you read the bottles of ready to use liquid supplements you will find that carrier/major constituent is water (distilled or RO). So my point beingwhat you have will mix with the RO water just fine>>
I wanted to make sure that it was safe as well as purpose serving for my reef creatures.
Thanks so much!
<<Happy to share! EricR>>

Switching to RO, what to remineralize with?   8/3/10
Hi WWM Crew,
Just a quick question for you all, if I may. First the details specific to my question. Tank #1 is 55 Gal. housing one 12 inch Red Devil. Tank #2 is 100 Gal. housing various Malawi and Tanganyika cichlids. Water for tank #1
is tap water plus half dose Rift Valley Salts(1Tablespoon Epsom salt, 1 Teaspoon baking soda, 1 Teaspoon IO sea salt mix per 10 gals. water). Tank #2's water is tapwater plus standard dose Rift Valley Salts. This method
has worked quite well for years. Here in a few days I'll be moving and unfortunately my new home has terrible tapwater, in particular NO3 levels in excess of 40 ppm. So, I'll be using RO/DI for my pet fishes and RO for
my potable. Question is, should I use a product like Kent RO Right to remineralize in addition to the Rift Valley mix?
<Not necessary in this case.>
Or, would the Rift Valley mix (with adjusted doses to match KH, DGH, and Ph to that of current water chemistry) alone suffice?
<Rift Valley salt mix will be fine. RO Right is primarily for use in situations where soft water fish are being maintained, and little to no other minerals will be added. With a Rift Valley salt mix you're adding all the general hardness via Epsom salt, carbonate hardness via sodium bicarbonate, and the trace minerals via the marine salt mix.>
Thank you very much for the awesome website and even better source of knowledge and experience.
Take care,
<Thanks for the kind words. Cheers, Neale.>

Elevating ORP in RO Water 07/16/10
Hi all!
<<Hey there Tina!>>
I'm sure you have answered this but after searching for 2 days I can't find it.
<<Mmm, okaydoes happen>>
What can I do to raise the ORP in my RO top-off water for my reef tank?
<<I dont know why you would need to, really (I dont recall ever hearing of anyone worrying about or bothering with raising the ORP of their make-up or top-off water). Butthere would be a few ways to do this I think. Either through increased aeration before use (also useful for blowing off excess CO2) or adding a bit of Hydrogen Peroxide to the water (do research this latter method before attempting)>>
I aerate it for 24 hrs then buffer it & aerate for another 24 hours.
<<Excellentand should be sufficient here>>
I have to add about 4 quarts of water every day.
<<Okay, but really tells me nothing without the specifics of your systemwhich you have not included with this exchange>>
I am adding it slowly over the day in a small stream in an area of high flow.
<<Very good>>
When I start in the morning, the ORP is between 350 & 355. The ORP drops over the day to about 275
<<Hmm, interestingand may be telling about your RO water which may contain organics and thus dropping the ORP. Perhaps it is time to replace the membraneor maybe add a DI cartridge to the unit. ButORP is a very complex dynamic that is not easily understood. A drop in ORP is not necessarily an indication something bad is going in to the tank. I do very much suggest you do some studying-up Heres a good place to start: http://reefkeeping.com/issues/2003-12/rhf/feature/index.php (This article has three partsdo read them all)>>
and after the water is all in the ORP will slowly start to come up. I have tried adding the water at night but then the next morning the ORP has only come up to about 330. Is there something I should be adding to the water besides the buffer, or is this just one of those things you have when using RO water.
<<Not so much an issue with the RO as simply a dynamic of adding anything to the tank>>
My ORP will drop to about 330 during the day if I don't add any water.
<<This drop in ORP is likely a result of the pH rising during the daylight hours>>
I would add the water all at once but was concerned that 4 quarts of water would change the salinity too quickly for my sps corals.
<<Slow changes are generally better than quick ones. To be honest, I wouldnt worry here. ORP is always in flux in our closed aquatic systems. But if you want more control reI suggest the addition of an ozone generator employed with a reactor (my preference to using ozone in conjunction with your skimmer)when employed correctly, O3 can be very beneficial to a captive system, aside from (or as part of) elevating the ORP>>
<<Happy to share, Tina Eric Russell>>

R2: Reef Setup Critique 06/10/10
So Eric, we are down to one issue, the RO water.
Demineralization would be an issue even with the Ca reactor on the system?
<<Can be, yesdepending on coral species and stocking densities. I find on my heavily stocked SPS (predominantly) system that even with a Calcium reactor and a Kalkwasser reactor I often have the need for additional supplementation>>
So if I understand you correctly, could I run the RO directly into the Kalk reactor, then have the top-off system trigger the pump for the top-off?
<<Pump? If the RO is hooked up to the Kalkwasser reactor wouldnt the water be pushed to the sump via the mains water pressure?...thus, why the need for a pump (or does the RO utilize a pump to boost said water pressure?)? At any rate, yes, if the air-switch in the sump is controlling a solenoid that turns water on/off to the RO units then it is feasible to route the RO to the Kalk reactor and then on to the sump>>
On another note are you a fan of the Tunze Wavebox 6212 (I give that model because I am not sure if the 7095 will control the 6515)?
<<Not especially, though Ive not used onemainly because I dont like the size/bulk of iteven in my 8 display>>
Thanks again,
Mike Z
<<Happy to share EricR>>

RO water ph + tank ph = very stressed/sick fish?
Low pH in Marine System Causing Serious Damage to Inhabitants 1/11/10

<<Hi Richard.>>
I am new to the salt water aquarium hobby, and am realizing there is quite the learning curve!!
<<A large percentage of hobbyists quit the hobby within one calendar year of beginning a tank, usually lack of research/knowledge. We do what we can here to fix that.>>
I have a 150g reef tank and my fish seem very stressed (still eating but white and black spots, cloudy eyes, more aggressive behavior) and my Kole tang looks like it's on its last couple of breaths. Also my hammer and
frogspawn corals have thrown off almost all their heads look like they are almost dead.
<<There is indeed something wrong with the environment. (tank chemistry).>>
I installed an RO system and an auto top off in November and since then I've been having a few problems.
All my tank parameters are fine except ph. (Ca 420, KH/Alk 10.9, Mag 1250, sg 1.025, ph 7.80 during the day dropping to 7.70 at night, temp 78.0) The problem I have been having for the last couple of months is low ph, and try as I might I can't seem to get it to come up.
Well today after reading all about RO water, I realize that I should have been buffering my top off water, so I tested my
<<Indeed, this is the issue. Should be buffered and aerated for at least 24 hours before use.>>
RO water and it has a ph of 6.62!
<<Sounds about right for straight RO water.>>
My question is could this be causing all my problems with my fish and corals? Is there anything I can do for my fish immediately?
<<I would start with multiple water changes, perhaps 20% ever 12 hours or so until you can bring it up to within acceptable parameters.>>
I will start buffering my top off water and weekly tank change water, but is it too late to help my fish? Any advice is greatly appreciated!!
<<See above, you are on the right track, and read here;
Good luck.>>
<<Adam Jackson.>>

Buffering and Quarantine: Water Chemistry Post-RO filtration and pH Acclimation 12/20/2009
Dear WWM Crew,
<Hi Angela.>
Thanks again for your generosity! We greatly appreciate your gifts of knowledge, experience and valuable time! You do a wonderful job of helping the novices and pros alike. Thank you so much!
<Thank you for the kind words.>
Just two brief clarifications today.
First, I have begun pre-buffering my RO water with Seachem Reef Buffer after discovering that it was dreadfully acidic.
<Which is usually the case post RO.>
I have not noticed any significant changes so far but wanted to ask how much this will effect the ionic balance of my water. Would it be better to use the Seachem Reef Builder product instead, or perhaps nothing at all? Of course opinions vary on this subject. FYI, I have a lightly stocked 110 gallon reef system and I don't think that water parameters are needed in this email.
<It never ceases to amaze me that we (and I include myself in this statement) filter everything out of our water only to put most of it right back in again, but I digress. In any case, the method that works for me is this. I add simple baking soda to the water to get it either neutral or slightly caustic. After which, I add my salt mix; l after that has all dissolved, I test again and make any adjustments that may be necessary.>
Secondly, I have set up a 30 gallon cycled quarantine system in anticipation of some fish from Live Aquaria.com.
<Bravo on following QT procedures.>
From what I understand, pH shock is perhaps the most common cause of death with mail order specimens.
<Yes.><<Mmm, much more the change in charge of ammonia coupled with too high pH in new water. RMF>>
I was considering keeping the system at around 7.8 using the Aquarium Pharmaceuticals product "pH Down".
The reasoning being that the water will be quite acidic on arrival. Does this sound like a wise choice to you?
<That would work, but you are putting extra work upon yourself. Easier, would be to drip acclimate the new fish to the QT water pH and then introduce.>
What if the bag water is significantly lower or higher in terms of pH?
Is it advisable to adjust the quarantine water in accordance to testing the bag water before the fish go in?
<No, again, better the adjust the bag water (smaller volume, much easier to adjust) to the QT tank.>
Thanks so much!!
<My pleasure as always.>

RO\DI systems: pH drop after adding salt mix.  6/18/2009
Hey folks.
<Hi Jason, how's TN?>
My freshly made RO/DI water shows Ph 9.8 out of a brand new unit.
<Wow, that is high. What is the pH of the water out of the tap?>
6 Stage 3 RO/3 DI cartridges. Is this good or even what it's supposed to be?
<The pH of the output water is dependent upon the pH of the water going into the unit.>
Using a Hanna tester.
<May want to get a different test kit to sanity check your tester.>
Also, why does my Ph drop in my make-up water garbage can after I add salt?
This is after it had a chance to aerate for a day and get Ph up.
<The output water is stripped of its buffers, the pH quickly drops as it gets mixed with oxygen and carbon dioxide in the air.>
Seems counter productive to initially have Ph where it's supposed to be only to have it drop, then have to raise it with buffer to be the same as tank water
<Quite normal. Water out of a RO\DI unit has no buffering ability at all, so the pH changes based upon what is added to the water..

Water Conditioners 1/24/09 I have a tap water filter that I have been using for some time now. But I have been having trouble finding the Electro-Right and the PH Adjuster that I add to the water. It seems that these two products have been discontinued. What can I use in their place? <Are not discontinued. Drs. Foster & Smith handle these products. Look here. http://www.drsfostersmith.com/product/prod_display.cfm?c=3578+4395+4492&pcat id=4492 Thanks for your help. <You're welcome. James (Salty Dog)>

Seachem Prime, SW use, and RO waste water as well    12/21/08 On my freshwater tanks i always use prime in my 24 hour aged water prior to conducting a water change. <A good practice> For my saltwater tanks i also use prime prior to mixing my salt for partial water change. I now have a RO filtration system fitted, and would like to know if i need to continue to use the prime. <Mmm, not necessary. For browsers, this product desc.: http://www.seachem.com/Products/Conditioners.html> I have started to use the RO water for drinking and for topping up my sump. Can i continue to use my tap water plus prime for my partial water change on my salt water tanks, or is it best to use the RO water. <Mmm, really depends on the nature/constituency of your source/tap water... and your goals in using the RO... but if using tap, I would use the Prime> It seems to be a very slow process waiting for the trash can to fill with RO water, and the waste involved is very high. Regards Alan <Mmmm, I would think about ways to use the vented "solute water"... I have run out to my pond before and/or to a cistern to in turn water my garden. There's really not "that much" different than the tap... so, you might very well be able to simply collect this "waste water" and use in on your freshwater systems. Bob Fenner>

RO/DI Aeration 04/06/08 Crew, <<Matt>> I just have a quick question for you today. <<Okay>> I just hooked up my RO/DI unite from Thefilterguys.biz and was wondering what you meant by "aeration". <<Aerating the newly filtered water helps to expel CO2 and oxygenate the water>> Can I just put a powerhead in the tub of salt and top off water for circulation, or do I actually need an airstone also? <<Water circulation, in the form of a powerhead, is quite acceptable. Anything that moves/disrupts the surface of the water will aid in gas exchange>> Thanks for your help, Matt <<Happy to assist. EricR>>

RO/DI QuestionFlush-Valve? 03/26/08 I just have a very quick question for you all today. <<Okay>> I am going to buy an RO/DI unit this week from AirWaterIce.com. <<Nice gear>> My tank is only 55 gallons, so I do not need a ton of water which means that this unit will not be on all that often. <<Mmm, I guess that depends on the size of your water storage containers/your husbandry practicesbut I would still think you would use it at least once a week>> I have heard that is not good to let it sit without being in use. <<If for long periods, nobut if the unit will be run a time or two each week it will be fine>> Because of this, I was wondering if it would be smart to buy one with an automatic flush on it because it will be sitting? <<Hmm, I dont know of any automatic flush devices for these unitsthough I guess if you had a servo to turn the valve and a solenoid to control water flow.. The flush device is likely manual, regardless of its namebut yes, flushing the membrane before each use will increase its longevity, no matter how often you use it>> Thanks for your input. Matthew Diethorn <<Happy to share. Eric Russell>>

Reverse Osmosis water with minerals 01/08/2008 <<Hello, Andrew here>> I recently purchased blue mushrooms and three weeks has passed and I'm beginning to notice some of the mushrooms are detaching from the live rock. I think this all began when I added reverse osmosis water with minerals for daily top offs. The minerals are sodium bicarbonate and sodium sulfate. I probably should of pay more attention when I bought the water. <<Very true>> What should I do? please help. <<I would do a couple of 25% water change, 2 days in between changes, with standard RO or RO/DI with nothing added to it. Monitor the Shrooms for changes>> <<Thanks, A Nixon>>

RO/DI Water Prep 12/06/07 WWM Crew! <<Hey Daryl!>> FYI, I personally spoke with Sylvia Earle last week, she was at my college giving a presentation. <<Ah yes, a very well known and accomplished marine scientist, oceanographer, lecturer, etc....very cool>> She was only slightly concerned about degradation of the World's reefs due to harvesting for the aquarium trade; <<Indeed... More concern/damage re from other arenas, the hobby just happens to be an easy target>> however, she was very excited about recent advancements in aquaculture! <<Is likely the future of the hobby>> Now, for a quick question... I have a 75 gallon "reef tank" - I have around 80 lbs of live rock a few leathers, mushrooms and button polyps. For many years I've used our well water (actually, we only have a sand-point - probably not the best water!). <<A common misnomer I think is that most folks believe well water to be better/healthier than city water, without question. This can often be so, but with ground-water contamination being what it is these days it is always a good idea to test...not just for your wet-pets benefit, but for yours as well>> To help with my horrible hair algae problem, I've recently purchased a Kent Marine Hi-S 35gpd RO/DI unit. <<Ah good... I think regardless of the origin, all reef enthusiasts can benefit from filtering their source water. Best to start with a neutral/pure medium and add only what you want to be there...especially considering that much of what may be in the water that comes from the tap cant even be detected/identified by the average hobbyist. At the least, it can eliminate this as a cause/contributor when the time comes to find/diagnose problems in your reef display>> I've got it set up, discarded first 15 gallons, and ready to go. <<Okay>> After a lot of reading, I know I have to let the water sit for 24 hrs while being aerated (to drive off CO2 and prevent the water from being to acidic). Now, what else do I need to do? <<I would buffer the water before use to prevent it from burdening the buffering capacity of the display tank>> For top offs, do I need to "reconstitute" or buffer the water by adding certain chemicals, or can I just use this aged and aerated water directly for top-offs? <<I would buffer to a pH of about 8.3 which can be done with simple Baking Soda (Sodium Bicarbonate), though I prefer to use a mix of Seachems Reef Buffer at a ratio of 1to3 with Baking Soda. I find that the Borate and other earth elements in the Seachem buffer yield a higher and more stable pH boost than the Sodium Bicarbonate alone. Mixing the two together at this ratio works for me, and extends the Seachem product which makes it quite economical to use>> When one speaks of buffers, is it strictly regarding pH? <<Generally yes, as pertaining to the use of Alkaline materials to raise/buffer the pH>> I have never used additives in my tank (set up about 6 years) and I've propagated my toadstool leather several times and I've gone from about 5 Ricordea mushrooms to over 50 (I've been trading them to the pet store!). <<The use of additives is not a necessity for success...much/all such elements can be supplemented/replenished through frequent partial water changes with a quality synthetic salt mix>> I would like to move up to some LPS corals. What are the main additives I should be adding/testing for? <<Your goal is still balanced water chemistry with elemental levels replicating (or close to) natural seawater levels. What the addition of stony corals may mean, is that your Alkaline/bio-mineral elements may be consumed more quickly requiring either an increase in water exchanges or other form of supplementation (Calcium reactor, Kalkwasser, two-part liquid additives), dependent on the rate of consumption. In addition to any other testing you may do, weekly checks on Alkalinity, Calcium, and Magnesium should be performed during stocking and until you learn what your system needs...then testing can be done periodically to check if things are still stable or need adjustment. To gain a better understanding of these elements and their use, as well as their relation to each other, start reading here (http://www.wetwebmedia.com/calcalkmar.htm ) and here (http://www.wetwebmedia.com/watrqualmar.htm ), and continue looking/reading through the links at the tops of the pages>> Do I even need to add any additives? <<It is possible that you wont...other than buffering your fresh makeup water as previously mentioned>> What is the simplest way to go about this? <<The simplest?... As a general response to the numbers of hobbyists who will read this- It depends much on the size of the system, stocking density, and the needs of the organisms kept, as well as ones particular maintenance habits and husbandry skills...but...for you, and many others...frequent partial water changes is the simplest and single best method of supplementation...and has the side benefit of dilution of harmful elements too!>> Again, thanks for all your help! Daryl Lindstrom Jr. <<Happy to share my views. Eric Russell>>

Re: RO/DI Water Prep 12/07/07 Thanks Eric- <<Quite welcome Daryl>> I've been looking at three of Seachem's buffers (Reef Buffer, Marine Buffer, and Reef Builder) to be applied to RO/DI water. <<I am a big fan of Seachems product line (or at least most of itI do have issues with their Aluminum-based Phosphate remover). Either of the two buffers is what you want to use>> What is the difference between these three... <<Reef Builder is an alkaline product that will bolster buffering capacity without raising pH. The two buffers will boost pH and support alkalinity as well as provide additional bio-minerals. The two are blended products and I would think the only difference between the REEF and MARINE blends is in the proportions of the individual elements>> Which should I use as the buffer for the RO/DI water prep? <<As statedeither of the buffers for this purpose>> Here is what I'm thinking (kinda hurts lately...next week is finals week!)... <<Mmmlucky you [grin]>> Use Marine Buffer for RO/DI water prep, bring pH up to 8.3. <<Okay>> In the display tank, if needed, use Reef Builder to raise carbonate alkalinity, along with Reef Advantage Calcium (I know it has long-term side effects of Cl buildup...I'm just trying to easily get started here). In addition, use Reef Plus as a full-spectrum supplement. <<Nahbetter to use one of the two-part liquid for this>> RO/DI water prep -> Seachem's Marine Buffer Display tank -> Seachem's Reef Builder, Reef Advantage Calcium, and Reef Plus. Test for pH, alkalinity and calcium and use above products as necessary (probably won't need much as I have a rather light load of corals). <<Do look in to the two-part productsless chance for creating an imbalanceand dont forget about your Magnesium (you read where I indicated?)>> How does this plan sound to get things started? <<You have my opinions>> I appreciate your time and assistance. Daryl <<Happy to help. Eric Russell>>

R2: RO/DI Water Prep 12/07/07 Thanks Eric- <<Very Welcome Daryl>> What "two-part liquid" products do you recommend... are they sold by Seachem? Daryl <<None by Seachem, but E.S.V. (B-Ionic) and Two Little Fishies (C-Balance) are both good choicesand AquaC (Complete) has a product out now as well. Cheers, EricR>>

R3: RO/DI Water Prep 12/09/07 Eric- <<Daryl>> Sorry for bothering you so much! <<Not a botherreally>> Here are my stats (not so good!) Ca 340 ppm Alk 2.74 meq/L <<This/these are not bad>> Mg 2020 ppm (yikes! I've never used supplements - likely from my well water?) <<Yes>> I've wondered why I can't keep snails alive very long! <<Hmm, not necessarily relatedlikely something else in your well water>> I'm still in the process of setting up my RO/DI system, by using this water; hopefully I can get my Mg lowered. <<Yesa slightly elevated Magnesium level is not a large concernbut this is too high>> After consulting several articles and an online "reef supplements calculator", it appears we are shooting for Ca ~ 425 ppm and Alk ~ 3.2 meq/L. <<This is finebut so would be readings of 400ppm Calcium with an Alkalinity level of 3.0 meq/L My point beingdont get hung up on what these calculators say you should have, they should only be used as a guide. Read through the links I provided previously and learn for yourself what needs to be>> Will take me a while to bring these numbers up! Daryl <<All should balance once you get that filtering system working and do a couple large water changes. Regards, Eric Russell>>  

R4: RO/DI Water Prep 12/14/07 Thanks again, Eric! <<Happy to help, Daryl>> Last weekend I replaced 15 gallons with RO/DI water. <<Is a start>> I tested the water today (Thursday)... Salinity: 32 ppt <<Better this to be closer to/at average NSW concentration (35ppt)>> pH: 8.2 (will buffer up to 8.4) Calcium: 390 ppm Alkalinity: 3.89 mEq/L Magnesium: 1500 Everything looks good to me! <<Indeed>> Is there anything else that I should really be testing for? <<Mmm, for your make-up water, nofor your display, yes (Ammonia, Nitrite, Nitrateand Phosphate, if in question)>> Also, I have a horrible hair and bubble algae problem!!! <<Likely attributable to the previous use of well waterthe addition of the RO-DI filter should help here>> To remedy the situation, I now have the RO/DI unit, and I also purchased a Turboflotor protein skimmer. <<The addition of a skimmer is a definite help/benefit as wellas long as it performs>> Is there anything else I can do to get rid of this nasty hair/bubble algae? ...or just wait it out? <<Patience if keybut weekly manual extraction may speed the process>> Also, I have "Bio Balls" in my sump as part of the wet/dry filter. Do you recommend removing them? <<For a reef system where the objective is to keep measurable Nitrate below 5ppmyes. These filters/this media do have a purpose, and in systems that can tolerate a bit more Nitrate (FOWLR or FO) they are very helpful with large shifting bio-loads. But the plastic media does not have the ability to completely process the nitrogenous compounds to their non-toxic (or at leastmuch less toxic) elemental formsand when this media is exposed to air as in a wet-dry filter such as yours, it can be so efficient at what it does as to produce more Nitrate than the available rock/sand can process causing Nitrates in your system to remain higher than desired. Thus the common label among reefers for this type filter of Nitrate-Factory>> I've attached pics of the tank and wet/dry filter just so you have an idea of what I'm dealing with. <<I see them, thank you for this. Im especially happy to see it appears the Turboflotor is working well>> Thanks a bunch, really! Daryl
<<A pleasure to share. Eric Russell>>

Finally Got a RODI!! - 03/24/07 Hello all, <<Hey David>> I hate asking questions with such a plethora of info to be found here.  But after hunting I'm still unsure of what practices to employ after installing my RODI unit. <<No worries...let's see if we can figure it out>> I have dumped the first ten gallons as told to do per instructions. <<Ok>> Now I'm wondering since I have read of so many other people adding different stuff such as buffers, etc to the RODI water, what are the MAIN things I should test for and possibly have to add along with salt mix to my new water? <<Well David, I use to indiscriminately buffer my filtered water "prior" to adding the salt mix with a mixture of sodium bicarbonate and Seachem's Reef Buffer (3 to 1).  But of late I've changed my routine and add my salt mix first, then test/add buffer as "needed."  I think you'll find if you do it this way you will precipitate less alkaline material out of solution from overdosing buffer>> We have Wisconsin well water that tests wonderfully each year for drinking purposes.  It is run through a sediment filter and a softener which I had been using straight from there. <<Hmm, has always been my understanding that it is not good to use water from a "softened" source as it loads the water with Na+ and Cl- ions which will eventually create an imbalance>> I added salt mix and just poured it in, no buffer or anything added with no worries.  This has been for years now and I've always been worried my water is the source of a phosphate problem. (no tests done just the signs have been seen). <<Possibly...but you should "test" rather than speculate>> Now I have the RODI located at a bar sink after the softener. <<Very good>> I'm pretty sure I have read this is what would be the best setup for my situation. <<Is...in "my" opinion>> SOOO whats next?... <<Sounds like it's time to filter some water and let it "age">> Is the RODI going to change the water so much that I should test for things I never tested for before? <<You should test calcium/alkalinity/pH of your mixed saltwater...but not just because you added the RODI unit...>> I have only tested for nitrates, nitrites, and CA in the past (all safe). <<Very good, though use of the filter unit should preclude having to test for nitrogenous compounds except in cases where you may suspect the efficacy of the filter membrane/DI resin>> Short of food I add nothing to the tank.  All seems well but when I pour in this new (pure) water what can I expect? <<Mmm, perhaps a healthier more "balanced" system...ultimately>> Is my skimmer going to freak out? <<No>> My fish? corals? <<No and no again...as long as you don't go nuts and try to do an 80% water change...do keep/use the water-change routine you've already established>> Is the hardness going to dive to a unacceptable level? <<...?  As in a precipitous event?...not from using filtered water.  Just make sure you measure and buffer (if even necessary) your alkalinity to safe/normal NSW levels>> Any foresight from the ones with 20/20 hindsight?? <<I very much recommend you continue reading through our information on water filtration, marine alkalinity, mixing and supplementing artificial seawater, and marine water chemistry/constituents in general.  I've listed some for your  review and to get you started>> http://www.wetwebmedia.com/h2opurifiers.htm   http://www.wetwebmedia.com/alkalinity.htm   http://www.wetwebmedia.com/seah2omixing.htm   http://www.wetwebmedia.com/seah2osuppl.htm   http://www.wetwebmedia.com/seah2omats.htm Thank you, David Conway <<Read-on my friend.  Eric Russell>>

Re: Finally Got a RODI!! - 03/25/07 Thanx for the links Eric. <<Quite welcome Dave>> It was a long read and I think I'm more boggled by what I've read then ever before. LOL  I guess it'll seep into my head later. <<Ah yes...can take a while to "sink-in" but do keep reading>> I still dont even own a test kit for alk or pH or phosphate for that matter. <<Mmm...considered by many as "basic requirements" to the hobby>> Remember I WAS just mixing softened well water (conditioned with Start Right) with Instant Ocean.  No chemicals whatsoever. <... these ARE chemicals... RMF> <<Yes...and "guessing" about your water quality>> Tomorrow is water change day.  Should I just do what has worked so far and let things be for now or use the RODI with no fear and test when I buy these kits? <<I would go ahead and start using the RODI water, mixed to a specific gravity of 1.026 with the Instant Ocean, and get some test kits as soon as possible.  You should also be at least periodically testing your display tanks as well, I suggest you obtain kits for ammonia, nitrite, nitrate, magnesium, calcium, alkalinity, phosphate, and pH (I really prefer meters for this last as it makes it easy to check "often") as a minimum, and then for anything else you think you may dose/supplement (e.g. iodine, strontium, etc.)>> Everything is going and growing somewhat well in all the tanks around the house for a few years now. <<Excellent>> I feel after reading all the science guy stuff that I'm the laziest Aquarist ever and adding the RODI is just making me have to buy a bunch of 20$ test kits just to make me feel my new "pure" water is as ok as what I was doing before buying the RODI unit. LMAO <<Maybe, but likely what you were "doing before" is a ticking time-bomb...things have been fine up to now, but...  As for the price of the test kits...Seachem offers a quality product at a reasonable price, and they offer some "combo" kits that are quite economical>> I'm sorry Eric I can ramble on...I have a short attention span too. <<No worries mate>> On another note check out my Sarco since our last WWM encounter.. pics attached and made smaller.. one after our heater accident as you recall, and one of it today.  It's got to be 2" taller and 3" wider now!! <<Excellent...very good to hear>> <<Happy to assist.  EricR>>

PRIME (SEACHEM) 3/11/07 How are you all doing? <Good thanks.> I have a question about the product PRIME from Seachem. I have a little system made to dispense Freshwater (R/O) from a 26 gallon trash can and a saltwater mix (1.023) that is in another 26 gallon. I have heaters in both and have power heads in both. My question is when I make new fresh water with the R/O maker, can I just implement the PRIME in the freshwater trash can? <Not necessary with R/O water, it removes the chemicals Prime treats.> Or when I'm ready to mix new saltwater and add it to my saltwater trash can should I put the PRIME in the saltwater mix? Where do you think the Prime would be more effective or does it even matter? <Unnecessary.> Sorry but two more question my tank has been cycling for two weeks now and I have been doing 5-10% water changes so far at the end of each week ( Only two so far). However, I also have real fine sand in the tank. Do I need to siphon the sand too. <I would not unless it has algae growth on it.> Or can I just pick up the die off from my LR with tongs and not have to stir up the sand. <Would work fine.> Because as you know if you suck to close to the sand you end up sucking up sand as well and I don't want to do that. The last question I have is my tank has already gone through a phase where I had brown algae and now it has turned green in the tank is this normal? <Yes> I  believe it is from all of the books and forums I read on this web site. Also can you all give me a good web site to go to that has detailed info on how the Nitrogen cycle works and the steps your tank goes through from beginning to end and also charts and pictures of what it looks like in these stages.  <Don't know of one with everything you are looking for.  Can start here http://www.wetwebmedia.com/FWSubWebIndex/fwestcycling.htm and see where it leads you.>    Thank you for all of your help! Jeff <Chris>

pH stored water   12/22/06 Hello Crew <Wayne> Sorry if this is a repeat question, but I can't seem to find the answer on your site. <Let's see if "it's" there... or add it> I use RODI water and store it in a 30 gal trash can.  I use SeaChem's reef Buffer.  The directions on the bottle don't indicate how much buffer to add to fresh water. <Is variable... depending on need, the make-up of source water... need to experiment...> It only makes suggestions on how to add to your main tank.   So after some trial and error, I've been adding 2 tbls per 30 gal of fresh water.  If I add more, I get cloudy water when I mix salt.  If I add less, than the PH never even gets past 7.8. <Mmmm... your RODI water... how are you "treating" it period? That is, do you aerate it after making it up in the bucket? Ahead of the buffer addition? I would> About 8 hours after mixing the Buffer, the PH is off the charts!  Bright purple, I can't even guess what reading this would be.  The highest my test kit goes is 8.8.  It's way beyond that.  Wait another 8 hrs, and the reading drops to 8.0 maybe less. <Mmm... aerate the water first... consider, try adding a simple bicarbonate buffer first (a few teaspoons of baking soda) allow this to mix for a few hours...> Any explanations for this? <CO2/acidic interaction> How long should buffered water be able to be stored and still maintain a good PH? <Several weeks...> What can I do to change this? <See above> I have an Aquaclear 50 powerhead, airstone, and heater in the mixing tank (trash can). <Good> Thanks for your help. Wayne <Thank you. Bob Fenner>

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> 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, Im 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, its ph is 8.2.  I have another 5 gal bucket for top off water (tank is only 30).  I use Seachems 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 doesnt 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 didnt 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> 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>> KATI/ANI Unit Woes Hello one and all- <Twice in one day! Back again, Ryan> I was looking you some advice from you fine people. I had recently purchased a Kati/Ani unit for my 125gal fowler(170gal total system). System has been running for 2 years. I have 2 MAG 12 pumps for circulating the water. For new water when I was using the deionizer) I add "Prime" chlorine remover, aerate, heat for a few days, then add salt then buffer if needed. I would check ph and alk.  I have had dozens of snails in the tank for about a year and now they have almost all died over the past 2 months. Plus my xenia that had been growing like a weed just fell apart. Now the tank has turned into a huge Cyanobacteria farm. All I can think of that has changed is using the new Kati/Ani unit. The resin in the unit has only changed color about 1/3 of the way after running a hundred or so gallons thru it, so I don't think that the resins  would be a problem.  Plus I have a monitor on the water output. I am thinking maybe my process for treating the deionized water is flawed somehow and a ph or alkalinity swing has killed off the snails and xenia.  Could you share with me how you would suggest preparing and testing it? <I have never used a KATI/ANI unit, but I found a great article about preparing water using one: http://www.pmas.org/pro/ credit due to Mr. Steven Pro, of course.  His steps are detailed, efficient, and his success evident.> I have read before that using "Prime" chlorine remover can make some water tests inaccurate? Would it throw of my ph and alk tests? <Never heard this, perhaps the manufacturer can verify?  Message boards like ReefCentral.com chemistry forum would be your best bet on this type of subject.> I also upgraded from a Berlin turbo skimmer to a Precision Marine Bullet 1. Easily get a cup a week of pretty dark skimmate. <Great> Are there any  tips you might have for using a deionizer? I have switched back to good old tap water for now until I am sure what is going on. Not sure if this is even part of the problem. My guess is that I should stick with the deionized water because now it seems like it is getting worse. <I would change as little as possible...and do lots of small water changes until you get a handle on this.> Also- What color would a poly-filter turn if there were phosphates? When I use one it always turn brown pretty fast. <Poly filter color chart is on the back of the package...sorry bud but I'm at work! (Shh....)> I am poor at putting thoughts into words, sorry if this is e-mail wanders all over the place. <No worries.  You'll get this under control, just keep eliminating possibilities and the result will be the cause.> Thanks for your time.  Dennis

Buffering RO/DI water 5/27/04 Hi Marina, <Anthony Calfo instead> Is the Kent Marine Pro Buffer dKH sufficient to reconstitute RODI water?  <most any common sea buffer will work fine. Do aerate in advance to reduce the amount of buffer needed> Or should I be looking at another product.  <I personally like Aquarium Systems SeaBuffer and most any SeaChem products. I've never been a fan of Kent products> thanks, I understand you are shorthanded, so I will wait patiently for a reply (well at least I will try to wait patiently:) thanks for your support. <best of luck, Anthony>

- Buffering RO/DI - Hi, Hope all is going well for you there.  I have a couple of questions please.  First, I use D/I water which I store in a 50 gallon plastic container.  I have read that R/O water should be aerated for 24 hours before adding the salt mix.  Is this also true for D/I? <Yes.> Also, I use Seachem's marine buffer.  Should I add this to my water before or after I add the salt? <Before.> And lastly, what action can I take if a particular batch of salt mixes to a higher than normal ph? <Limit the amount of buffer you add before you add the salt.> I use instant ocean, and have read that at times it can mix to higher ph than normal. <More likely due to differences in the source water and not the salt itself. Test everything before you make additions.> Thank you for your time, James <Cheers, J -- >

R/O-DI...HEAD SPINNING - 08/06/05 Hello Guys, <<Morning>> Been reading your site from start for my salt water set up, it's great and I don't know where I'd be without it. <<Thank you, glad you find it useful.>> I am gathering all the components before I start anything.  I want to use a DI unit, my water is well water and very hard.  Iron stains all over the house.  But now I read I may be removing helpful things from my water, is this true?  Please help a rookie in the hobby. <<No real concern here, the DI unit will provide more help than harm.  Just be sure to buffer the output water before use (simple baking soda...or my personal fave, 2 parts baking soda to one part Seachem Reef Buffer).>> THANK-YOU DAN PALMISANO <<Regards, EricR>>

Buffer Dosage - 08/08/05 Thank you for all your help and fast reply.  The buffer you described never mentioned the water ratio, or do I follow the ratio on the Reef Buffer? ""Just be sure to buffer the output water before use (simple baking soda...or my personal fave, 2 parts baking soda to one part Seachem Reef Buffer)"" Thank-you in advance DanP <<I would start with the dosage recommended for the Reef Buffer alone...test this for alk...then adjust as needed.  EricR>>

Conditioning RO/DI Water 08/26/05 I have a 55 gallon saltwater aquarium set up for 2 yrs now.  I just purchased a ro/di system and want to know what do I need to do to water before I put in tank? <<Congratulations. IMO, RO/DI systems are one of the best investments you can make. The water from the RO/DI unit can be used directly as top-off water. You can also use it for water changes. Just mix with salt and age.>> I was told to use Kalkwasser but not sure about how to use it. <<Kalkwasser is made by adding quicklime or lime to water. The Kalkwasser solution is then added to a system as top-off water or in dosing systems. Using Kalkwasser is one method to supplement calcium and alkalinity (carbonate) to your system. There are several reasons to use Kalkwasser: supplement calcium (reef life use calcium so in a closed system with stony corals, calcium is being depleted), raise the alkalinity to buffer the pH in the system and precipitate out phosphate (which is good for algae and bad for reef keepers). There is lots of material here on this topic. Please search and read up on these topics: Kalkwasser, Kalkwasser slurry and top-off systems.>> I was also told by separate source to use Kent Marine Superbuffer-dKH. Will the Superbuffer be sufficient to use. <<Since you are asking about both Kalkwasser and Kent's Superbuffer, I'm guessing that you have an issue with alkalinity and pH. There are pros and cons associated with using Kalkwasser versus a product like Kent Superbuffer. Considerations include cost and simplicity. Using Superbuffer is simple but in the long wrong, more expensive than Kalkwasser or Kalkwasser slurry. Kalkwasser dosing systems can be fairly simple or more complex and of course the initial cost varies. Kalkwasser slurry is very simple but not for everyone. Search and read up on Kalkwasser slurry, top-off systems, dosing systems, Nurce, Nilsen Reactor.>> Of course I know to get salinity right. <<Not a worry. Getting the salinity right is what you already do when changing water. The only difference is you will be using better water in your water changes.>> This ro/di has me all thrown off some, how soon can I add this water to tank. Can I add it as soon as I add buffer and get salt and temp right?<< I hope I have cleared up some of your confusion. Again, RO/DI water is great for replacing water that has evaporated from your system. As make-up water, it goes directly into the tank without mixing salt or buffering. For water changes, RO/DI is much better than tap water. Do what you already do and mix the salt water and let it age before doing the water change. Don't add anything to it. Finally, there are many ways to address alkalinity and pH issues. Don't forget to read up and understand why alkalinity and pH are important to your system. Good luck and cheers - Ted>>

Re: Conditioning RO/DI Water 08/26/05 I have no pH or alkalinity problem. I have had nitrate and brown diatom problems. <<Using RO/DI water is one of the first things to do to combat algae and diatom problems.>> What do you mean by age water? <<Unless you are dealing with some kind of tank emergency and you don't have the opportunity to age the water you should mix up saltwater to the correct specific gravity and temperature and aerate/circulate it for a day or so before putting it into your system. The better salt water mixes contain a buffer so adding a buffer is not necessary.>> So I can take my RO/DI water and put it directly into the tank at temperature without adding anything to it? <<I see from my previous answer, I added to your confusion. Sorry. Yes. Many auto top off systems put RO/DI water directly into the tank. If the RO/DI water feeds a Nilsen reactor, then the addition of buffer is unnecessary. On the other hand, if you store the RO/DI water or place it into a reservoir to feed a top off system, you can aerate and/or buffer the water>> It has very low pH so I figured I would at least use pH buffer for top off water? <<Many people recommend aerating the water to drive off excess CO2 or adding a buffer to RO/DI water to raise the pH before use. You can also make your own buffer using washing and baking soda. Search WWM for more information. Cheers - Ted>> RO water applications - 8/11/03 Thanks for your advice Mr. Calfo!, or  anyone else that may reply!! <always welcome> I wondered if you would mind just clarifying a couple of points you made. With regards to aerating RO water before you use it, what is the reason and why would there be Carbonic Acid/ or CO2 in it in the first place?   <natural acidity post-demineralization. When you hear about "temporary" pH and its adjustment... this is what they are referring to. Although you can (and should) aerate the RO/DI water to raise the pH... the water still is unstable (could go acidic again easily) because of the lack of ALK/hardness> Is it part of the filtration process?, and also how long would you recommend to aerate the water for?. <12-24 hours> Secondly, if you do not aerate the RO water sufficiently before demineralizing and adding salt will the carbonic acid eventually be driven off with sufficient aeration/movement, or would  it be to tightly bound for it to be driven off, thus resulting in the poorly buffered water as mentioned. <if you neglect to aerate it and buffer it before using it as evap top-off or for salting, you will find that this water puts a measurable burden (consumption) of the main system's ALK and/or pH> I ask this because it was my practice to mix salt & minerals and then aerate which I suspect is the reason for my depressed!! pH!! and my depression!! <yes... at least contributory. Do adjust your water treatment, mate> and seeing as though I have just filled my new tank with RO water, (purchased as ?5a bottle) aerated after salt has been added, (another great little tip from my soon not to be LFS), I feel,  I might have a more stable tank temp wise, but in exactly the same place as I was before with the pH!!!! Aghh <yes, indeed.... the problem is not severe, but simply a waste of buffers in the main display which causes these nagging problems> Then if this being the case should I start more water changes with the properly aerated, water, or just stick to my regular routine? <hmmm... not sure I follow the question. If its a matter of RO vs. Tap water, I would always recommend properly aerated and remineralized RO or DI water over even the best tap water. Stability/consistency vs. risk of seasonal changes to your source water> Last but not least, should you remineralise the RO water every time you use it or, only after two or three water changes due to build up of minerals? <with every use... even if only in a small amount. Let your tests of pH and ALK over time determine how much to use> That it!! Thanks a million for your advise and help, Rob <best regards, Anthony>

Explain This to Me Like I'm a 3rd Grader!!! A few questions please...I've been scouring your site for a few months now... I read your articles/FAQs on alkalinity and pH. If your water is hard, does that mean pH is high and alkalinity is high..?  <usually they are hand in hand... although it is very possible to have a high pH and low ALK (unstable water)>  ... or does water softness have different effects on chemistry?  LFS guy says since my water is R/O I don't need to aerate my 5 gallons of top off water that I go through every week (stored in plastic 'Red Sea' 5 gallon container with screw tight cap and air- escape- capped- hole- nozzle- thing stored in my food pantry throughout the week, but I like to shake it up a tad during the walk with it to the aquarium).   <all RO water has to be aerated before it is buffered and used for any purpose> Out of the 10 LFS's or so in my area, they were the only one who could answer detailed questions about their R/O setup, and it looked good with extra chambers for stuff, one specifically for silicates, and the store's been open less than a year (aquatic aggression in Fresno California) am I doing this wrong? <without aerating... you wasted buffers. Not a crime... but not good practice either> Do I need to aerate R/O water from the LFS, they claim to buffer with Kalk and use Red Sea salt?? <do a pH test to confirm the need or not: test the pH and then aerate vigorously for 6-12 hours and then test again... the pH should not change. If it raises, you need to aerate it indeed> Also, I use the Via-aqua protein skimmer, it has a built in UV that I have now turned off thanks to Anthony....as I'm supporting a mandarin......okay, okay....2 mandarins, 1 male 1 female, both fat and sassy and beginning to get their freak on...no other fish.... it also has a chamber for a mechanical filter pad (laced w/ carbon).  I only used the last one for a week.  I have thrown in some small live rock pieces into this chamber (maybe a gallon of water) with some Gracilaria, it's maybe 3-4 inches wide and 12 inches deep or so....you know, ' fuge style... I don't think I'll put sand in there though.  But I need a small submersible light (for reverse photo period) to dip in here that will complete the ' fuge and keep the Gracilaria alive.  do they sell such lights???    <there are some neat daylight colored LEDs hitting the market. Also some pool and garden pond lights to do this job are available> I really feel it's a legit 'fuge.  whaddya think?? <if it's fishless... it's a 'fuge to me <G>> Considering you're my most trusted authority!! thanks!! I love you guys... and Marina too!! (wink wink) <who-ha... Antoine>

RO Redux... Why is it necessary to buffer RO/DI water? I recently read this on your site...... ******************************** Source Water Pre-Treatment So if I don't wait 24 hours before adding salt this can interfere with my alkalinity? <Essentially, yes. Freshly-"produced" RO/DI water has very little, if any buffering capacity, and additions of large quantities of this water, without some form of buffering, can contribute to depleted alkalinity in your system. I think it's good practice to aerate and/or buffer RO or RO/DI water at least 12-24 hours before use. Hope this helps! Regards, Scott F> ******************************** http://www.wetwebmedia.com/rofaq5.htm after researching and asking some groups, I posted this and asked for some opinions......I came across this response....and I wanted to know if there was any truth to what this guy is saying.... ******************************** Yes, it's wrong....When water evaporates from your tank, only pure water is evaporating.  Alkalinity is not evaporating.  Nothing else is evaporating. <True, but the point is- if alkalinity is being depleted by other sources, using water with no buffering capacity will not help the situation....> So, simply topping off with pure RO water will have no effect on the buffering capacity of the tank. <As stated above- in general, this statement is true...But the point is, once again, that in a situation with already depleted alkalinity, the effect could be detrimental..> I think what this guy is seeing, is that something was using up the alkalinity, possibly from coral growth, and he's just blindly blaming it on the RO water. <Wrong> If you notice your alkalinity dropping, you can either use a buffer, I believe Kent and SeaChem both have one, but you must be careful.  Adding a buffering supplement only, could have a negative effect on your calcium levels. <Potentially true...But may be taken out of the context of the original conversation here...> The other alternative is to drip Kalkwasser for all your top off water. Kalk will add the alkalinity and calcium at the proper proportions, while keeping pH up where it should be.  The only drawback is that it must be added slowly, otherwise it could push your pH up through the roof. <I caution against using Kalkwasser to make up water lost to evaporation, as you will be at the mercy of the atmosphere (i.e.; the evaporation rate) to determine your calcium dosing. Better to test water regularly and determine your system's needs rather than just randomly dose Kalkwasser. Kalk is great stuff, but, like anything you add to aquarium water, it's important to test, then tweak, as John Tullock is fond of saying...Hope this clarifies things a bit...Regards, Scott F> ******************************** Thanks,  Keith

- RO/DI Preparation - Hi, I have another question. <Ok.> I have purchased an RODI unit.  Is it best to add salt, then buffer (if needed), then calcium (Kalkwasser)? <I would add buffer before the salt.> Or is it better to add the calcium straight to the tank. <And yes, I'd add the calcium directly to your system.> What I'm thinking is that I should get the water ready to go at all the optimum levels, Salinity ~ 1.024, KH~10, Calcium~400 ppm and then use that water as part of a water change.  Would you agree? <Not really - best to add calcium to your tank directly, otherwise buffer the RO/DI water before adding salt.> Thanks, -Brent <Cheers, J -- >

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

- Water Prep - Hello All- Thanks for looking at yet another question from a saltwater newbie! I just got a 5 stage RO/DI unit for water changes for my saltwater tank. I am little confused as to the process of water preparation...What exactly does aerating mean?  Do I simply put new water in my trash can and heat and let it sit for 24 hours?  Do I have to leave the lid off? Do I have to use an air stone? <Add the air stone, I'd leave the lid on, and let it bubble for at least 24 hours.> I plan to put new water in trash can, heat and run powerhead for 24 hours, then add salt and let mix for another 24 hours.  All of this will be with the lid on, is this wrong? <No... I leave the lid on so that bugs, dust, and whatnot stay out of the water.> I will then test for PH and alk, and add Seachem Reef BUFFER/BUILDER accordingly. <I'd add the buffer ahead of the salt - it's a safe bet that the RO/DI water will need it.><<RMF would add, if necessary, later... AFTER the salt mix is dissolved, the water tested.>> Please let me know if this process is not correct. Thanks in advance, Jeff <Cheers, J -- >

- Which Water to Use? - Hello Bob. <Actually, it's JasonC today.> I recently read the WWM article dated 4/99 - http://www.wetwebmedia.com/water4maruse.htm I am struggling with the planning for my 120G reef tank and the issue of what water to use, Tap, RO, RO/DI or DI. Should I read the above info to mean that it is a good idea to pre-mix synthetic salt mix and my tap water and store for a week or more and it would then be safe to use in my reef tank? <Sure - it's what I did.> Additionally would this be as good/better than to use DI processed tap water? <What is good - what is better? If it means less work for you, or less money spent on an RO/DI unit, then perhaps using tap water is 'good' for you. It's your time - use it as you see fit.> If yes to the above, could I assume it is equally safe to store my tap water for same period and pre-mix with salt 24 hours prior to water changes? <I'd let things stew a little longer than that... I would mix/aerate the tap water for 48 hours, add the salt, and let that mix for 24 hours, then check/adjust your salinity and let that go for another 24 hours - so a total of about four days. In fact, it's time for me to go fill up the mixing container - thanks for the reminder.> Thank you for you assistance. <Cheers, J -- >

Treating Purified Water for Marine Use 6/10/03 Thank you Anthony. I will heed your advice on the NSW. <very good, my friend> Unclear on the top off water. I do aerate before. <yes... critical to raise temp pH and drive off carbonic acid/CO2> Not sure on the buffer. I use DI water that I purchase from one of the local fish warehouses. What do I need to do for buffering FW? Thanks again, John <just a little bit of SeaBuffer (mostly sodium bicarb) to reconstitute the demineralized water a bit. Else the soft purified water will consume excess buffers in the sea salt mix or main aquarium and cause your ALK to be flat/low. Use your test kits (Ca, ALK, pH) as a guide to know how much... and do browse through our archives here at wetwebmedia on the subject. A keyword search of water treatment/RO/DI/buffers with the google search tool on our home page will turn up many many FAQs of interest. Kind regards, Anthony>

Buffering RO/DI water & Going to the Source Hi Crew, <Thomas> I spent many hours on WWM archives trying to sort out questions about buffering RO/DI water before (or after) adding salt mix. I believe the WWM archives actually contain contradictory views on this, and certainly views contradictory to what I was told by the manufacturers of Instant Ocean and B-Ionic. <They do> I had an email exchange with the manufacturer of Instant Ocean and a phone conversation with the manufacturer of B-Ionic. <Hello to Bob> Below I quote the text of the email exchange with Instant Ocean that documents both these communications. (I did not just forward the email, so as not to divulge others' names and email addresses without their permission.) <I understand. You are welcome to show them mine> Make of it what you will. (I would think Anthony, in particular, should see this, as he clearly expresses a contrary opinion -- for example in CalcFAQs3 search for "unbuffered DI or RO"). <Will send all to him> I'm inclined at this point to believe there is no reason to buffer RO/DI water before mixing with salt or replacing evaporation loss. If that's really a misguided position, please let me know. Tom <In almost all cases I am in agreement with your statement. Bob Fenner> **************** My original message to Instant Ocean: Hi, I use Instant Ocean. I recently got an RO/DI unit to get pure water to start with. Now I heat and aerate the RO/DI water for at least 8 hours. Then I add the Instant Ocean and heat and aerate this for at least 24 hours (usually more). I also use the RO/DI water directly for evaporation top-up. Question: Do you recommend adding some marine buffer to the RO/DI water? If so, would you add it before or after the Instant Ocean? Would you recommend adding the buffer to the RO/DI top-up water, even if not to the water used to make salt water. Thanks, Tom Reply from Instant Ocean:  Instant Ocean is formulated to provide all of the necessary buffer as is; you should not need to add buffer to freshly prepared seawater. In order to add buffer properly you need to know what your alkalinity is. I would suggest purchasing an alkalinity test kit so you can monitor alkalinity and know if you need to add buffer or not. Thank you My Reply back to Instant Ocean: Thanks. I do have an alkalinity test kit, and do monitor the tank, using B-ionic to adjust the alkalinity level. However, I'd read some stuff on the web that suggested RO/DI water, being stripped of virtually all dissolved solids, needs to be reconstituted back to something more "normal" before adding synthetic salt. Otherwise the buffers in the synthetic salt would be "used up" immediately. But I also got an opinion from the technical support person at B-ionic that synthetic salts are formulated to work with pure water (e.g. RO/DI water) and that using water with significant dissolved solids already in it potentially messes up the water the salt mix is designed to achieve. Your answer sounds consistent with this view. Hence, I conclude I should just mix the Instant Ocean with the RO/DI water for water changes, and monitor the tank's alkalinity over time, adjusting as necessary. For evaporation top-up, the B-ionic person said straight RO/DI water is appropriate, because I'm replacing pure water lost by evaporation with pure RO/DI water. He said the buffering capacity in the tank pretty much instantly adjusts the pH of the pure replacement water to that of the tank. Have I got all this right? Tom Instant Ocean's response: That is exactly right. It is impossible to formulate a sea salt that would bring tap water to natural seawater levels of all ions so any good sea salt should be formulated assuming it will be dissolved in purified water. The alkalinity (buffer) level of IO is already slightly above NSW when first dissolved. <Thank you for this... There are "special cases", the largest examples I can think of involve a desire to "over-supply biomineral and alkaline reserve for culture... boosted growth, use of carbon dioxide infusion, intense lighting, high biomass/concentration... that one might want to modify new water by "buffering" processed tap water, for use by itself... or after mixing synthetic salt mix if for change-outs... Antoine? Bob Fenner> 

RO/DI water 2/8/05 Hello again, I really did try to answer my question with Google search, but couldn't find a concise answer (hope there is one). <That's what we're here for!> Background: We just got RO/DI system. Output goes into a Rubbermaid trash can. There's a heater and small powerhead in that can. Periodically, water is taken from this first can and placed into a second Rubbermaid can. Salt is added. There's also a heater and small powerhead in this second can. After a while, specific gravity is tested and additional RO/DI water added to get the right level (I try to add extra salt initially). We've been using the salt water (at least 24 hour aged) for water changes. We've been using the RO/DI water straight out of the can for top-ups. I've learned that I should be buffering the RO/DI water (but don't know how - what do use).  <Buffering RO/DI water is not the only way to add alkalinity, but it is a convenient and safe way to do so. I is important to note that ultimately, Calcium and Buffers should be added in a balanced fashion.> Question: Given my approach described above, what would be the simplest way to buffer the RO/DI water? If I do this buffering, do I need to change my procedures for mixing and using salt water in the second container? If I do this buffering, can I continue to simply take water straight from the first trash can for top-ups. Thanks, Tom  <There are too many solutions to list! Each way has it's upside and downside. Here are a few of the most popular:  Kalkwasser: (Calcium Hydroxide or Calcium Oxide powder) These products are sold as "Kalkwasser" in pet stores, pickling lime in the grocery store and quick lime at the garden center. A couple of teaspoons per gallon are dissolved in the top off water and allowed to settle. Only the clear water on top should be added to the tank. Kalkwasser adds a perfect balance of Calcium and alkalinity (buffer). Kalk is fairly cheap and easy to use, but the solution is fairly caustic (watch your eyes!). Two Part additives: (Products like B-Ionic, Kent CB, Twolittlefishies C-Balance). These products come in two parts. One supplies Calcium and one supplies Alkalinity. They also contain other trace elements. These products are added directly to the aquarium. They are expensive, but easy to use, and you would use plain RO/DI for your top-off. Dry Ca/Alk supplements: Tropic Marin Bio-Calcium is the only one I am familiar with. These products contain both calcium salts and bicarbonate salts in a dry form. The powder is sprinkled directly onto the surface of the aquarium water. The powder can irritate corals if it falls on them un-dissolved. These products work well, are moderately priced and easy to use. The powder must be kept very dry or it will solidify. You can also use separate products for calcium additions and alkalinity additions (each dissolved in some RO/DI water), but balancing them may be more difficult. Hope this helps! AdamC.>

Calcium Query? Hi guys, My tank is running beautifully, but I have a question about calcium.  Stats: 40 gallon Temp: 78 pH: 8.5 KH: 8dKH Gravity: 1.024 Ammonia: 0 mg/L Nitrite: 0 mg/L Nitrate: 5mg/L Phosphate: 0.25 mg/L Cu: 0 mg/L Ca: 300 mg/L My tank is almost 6 months old (Day 178).  I have 40lbs of Live Rock, clownfish, 3 PJ cardinals, 1 Coris wrasse, dwarf lionfish, 2 cleaner shrimp, xenia, moon coral, red mushroom, 2 feather dusters and some hermits and snails.  I mix my saltwater for at least 24 hours with aeration and heater. I use Kent Sea Salt and Kent OsmoPrep with RO water. I was originally (3 months ago) using RO water and Kent sea salt then realized that I should be using some supplements to raise my calcium levels, which were 320 mg/L at the time.  I was told by my LFS that the OsmoPrep would raise my calcium, so I have started to add to with every water change (10% every 10 days or so). I have done several water changes with the OsmoPrep and my calcium levels are still dropping slowly, almost 10 mg/L a month.  My question is, Should I be using a calcium supplement as well as the OsmoPrep? Or should I be using another supplement rather than OsmoPrep that will raise my calcium and the trace elements I need to use RO water?  Thanks guys, Troy  <Troy, Kent Marine does instruct the user of Osmo Prep to add Kalkwasser or a liquid supplement for reef aquariums, so obviously the calcium present in the product is not enough for reef systems. James (Salty Dog)>

R/O water treatment part2 2/22/05 One follow-up question: If I use B-Ionic, is there any reason not to use it to treat the ro/di water in the Brute, before that water is used to make synthetic seawater or to top-up the tank? Thanks, Tom <B-Ionic and similar two part additives are shipped as two parts because mixing them will result in a useless insoluble precipitate. For this reason, they must be added separately (I even suggest several hours apart), and cannot be mixed in make up water. Also, you could add one or the other part to your make up water, but IMO, this would be complicating a very simple process. Hope this helps. AdamC.>

- RO/DI Aeration & Low pH - Hi Crew.  <Hi.>  Hope everyone is doing well.  <So far, so good... thanks for asking.>  If you could spare a moment, I have a quick (and very basic) question.  <Whoops... time's up. Kidding.>  Can you clarify what is meant by aerating ro/di water.  <Reverse Osmosis and De-Ionization - a filtration system applied to tap water.>  I have my top-off/water change water in 5 gallon buckets. I have 1 or 2 airstones placed inside the bucket. I let this sit, with a loose cover, for about 12 hours before I buffer, then let that aerate (with the airstones) for at least 6 hours before I use for top off or saltwater mix... is an airstone or two enough movement or should I be using a small pump?  <This is fine.>  I do have slightly low pH in my 55g reef tank...ranges from 8.01 to maybe 8.12 on its own. I add Kalk nightly (but not consistently) by Anthony Calfo's method of 1/16 tsp added slowly... I usually add at least 4-6 cups of this and it barely reaches 8.28. I'm starting to wonder if maybe I'm just not aerating the ro/di top-off water enough?  <Doubt that aeration or lack of it is your actual problem here... would test your RO/DI water to make certain... but after addition of buffers and salt, pH should be in an acceptable range. Would look for causes in your system... perhaps overstocked, needs a gravel cleaning, perhaps you just need to open a window and let some fresh air in the house - is the time of year when homes are closed up tight. Could be any of those or all of the above or something else; many possible reasons... suggest you spend some time going through our FAQ's on pH as this is not an uncommon problem.> Thanks for a wonderful site! Any comments or thoughts would be appreciated. Jan <Cheers, J -- >

Buffering RO/DI water - Anthony's Response on the Matter There is much, perhaps, to say here... and the matter is at least a little more of an issue with a higher/faster demand for Calcium/Alk in aquariums with heavily calcifying organisms. To try to clarify, lets compare the examples of mixing sea salt with three different qualities of water: demineralized (pure RO/DI of near zero total hardness)... medium hard water which includes a concentration of 100 ppm calcium among total hardness... and very hard water (as many folks have around the country) of say 250ppm of calcium among total hardness. If your brand of sea salt mixes up at 350ppm of Ca in demineralized water... what do you think it will mix up in the medium hard water that includes an extra concentration of 100ppm Ca? And what do you think it will mix up in the hard water of an additional 250ppm of Ca? Sea salt mfr.s cannot know exactly what the mineral content of your water is... it runs the gamut among users. From naturally soft, medium and hard (or very hard waters) to the different qualities of demineralized water (quite variable among RO units of various membrane ages/qualities) It is up to us as aquarists to test our source water and adjust it as needed in concert with each sea salt (they range among brand re: Ca at mixing from anywhere roughly between 250ppm for cheapo salts to 450ppm for premium salts). And of course, the issue of Alkalinity and other/lesser minerals/elements in your sea salt and/or source water is the same. Thus... to expect a sea salt to magically know your mineral hardness/composition(s) and expect it to adjust is... well :p Bottom line IMO - not all sea salts (quite the contrary) are formulated for pure demineralized water. Don't just take my word for it though... or the mfg claims for that matter... test the brands yourself and see how low they mix up (as if the high number of e-mails we get on message boards re: flat readings aren't good perspective). If you do not buffer average salt mixes up at least a little to the presumed average hardness of the mfg... then you WILL have the common problems that so many aquarists do with low or flat Calcium, Alkalinity, etc. Most aquarists do not (!) use RO/DI water... and most sea salts are not (!) formulated for this group. As for aerating... you will notice/see that freshly made RO water is high in carbonic acid. Rather than allow it to chew up buffers/Alk in your new seawater or your system water... you can simply aerate (off-gas as CO2) this acid and raise the (temporary) pH before buffering or salting. To the best of my knowledge, the above beliefs are matters of "science". That is to say, scientific realities (verifiable) and not just speculation. If I'm mistaken here... somebody please let me know! Anthony 

Deionized water question 5/23/05 I set up a tap water filtration systems for water changes for my 125 FOWLR setup...I use a 5 micron particle filter inline with a 1 micron ceramic ( reusable cleanable) filter in series with a De-ionizing cartridge from Pentek...The water it produces is around 0.2 microSiemens at a very slow rate of flow...Is this too pure, and if so what can be done? I have no nuisance algae, but a lot of good coralline growth...thank you. John Gugliuzza <If you are using DI, your target is 100% pure water, so "too pure" is not possible. Major components like calcium and alkalinity may have to be supplemented, but all of the trace elements that your animals need should be present in sufficient quantity in good quality salt mix. Regular partial water changes will ensure that these elements remain at acceptable levels in your tank. Best Regards. AdamC.> 

A Little Confused...Still - 06/14/05 Thanks for answering ALL my questions.............just a few more. <<Did you think I wouldn't <G>?>> If I do switch to using RO water should I gradually do that with my routine water changes and topping off water? <<This will work fine, yes.>> I should let the RO water sit for a few days before I use it right? <<My suggestion would be, as a minimum, aerate for 24 hrs. and then add buffer and mix/let stand for a couple hours before use as top-off...if adding salt mix (after adding/mixing buffer)...aerate and/or mix with a pump/powerhead for another 24 hrs. before use.  If you have the space/forethought, it's best to mix your saltwater and let it "age" for a few days before use.>> If I use RO water what buffers do I need to add? <<Can be done with simple sodium bicarbonate (baking soda), though I prefer to mix it (2 to 1) with a manufactured buffer for the benefit of the carbonate and borate salts of the latter.>> Are you talking about a pH buffer?....what else? <<pH and alkalinity, yes.>> And please recommend some brand names that you trust. <<I'm quite fond of the Seachem buffers (Marine or Reef...either will do) for quality and price.>> Ok.....that's it for now  :) <<We'll be here if you need us <G>, Eric R.

Alkalinity Quick question?  <<Sure...>>  It seems I have to add about 1 teaspoon of baking soda or SuperBuffer to my top off water every day to keep my alkalinity around 10 to 12.  <<By any chance is your top-off RO/DI water? This is pretty typical if so... RO/DI is demineralized.>>  Is that o.k. or am I adding to much to the system.  <<Probably fine... do be careful about bringing up the alkalinity too high. I wouldn't go over 12.>>  I have been doing daily testing and it has never gone over 12.  <<There you go then.>>  Thanks <<Cheers, J -- >>

RO/DI <Hi Henry>> I have been using RO water, aerating, adding buffer (if using the water for top-off), aerating again, adding salt and aerating before putting it in the tank. Now I have an RO unit with a DI stage and wonder if there's anything I should do differently. <<No. I can't tell from the above but I'm sure you aren't using IO in your top off, right? Just buffered and aerated RO/DI water? Good.>> I have read opinions in the WetWebFotos forums that DI water can leach electrolytes from any organics it contacts and that it is also too pure to add directly to an aquarium without some remineralization and replacement of stripped electrolytes. <<Yes, this water is essentially totally pure, so it can hold LOTS of stuff in solution, so it pulls those elements from wherever they will come from until everything reaches equal saturation. So, if you make a 50% water change this would actually lower the needed elements in your tank to the mean or mid-point between the old water and new. If your pH is 8.3 in your tank and you add 50% pH 7 top off water, your tank will read at the mid-point between 8.3 and 7. Short answer? Aerate and buffer your top off to 8.3 pH.>> Other than a buffer, like Kent SupercKH, what other chemicals would need to be added to DI water meant to be used as top-off water? <<Nothing unless you test for various other elements like magnesium, which can be low in salt mixes. I add a balanced buffer, that's it.>> Would you add the same chemicals if the water were meant to be mixed with salt for a water change? I suppose the salt mix already has some of the missing parts. <<I test my change water for pH, magnesium and calcium, just because all the salt mixes and the water they are mixed with are different. The results are fairly consistent, but it never hurts to check for the majors; pH, carbonate, calcium and magnesium.>>  Thanks, Henry <<You're welcome Henry, let me know if you need any more information, Craig>>

Kalkwasser and buffered RO/DI water In your well experienced and educated opinions would it be OK to use my RO/DI water in my trash can that I have buffered to 8.4 to make up my daily dose of Kalkwasser slurry that I add at night to raise my pH? <I would be concerned that the buffering compounds may react with and precipitate out the calcium from the Kalkwasser.> Or would it be best to use non-buffered straight RO/DI water for the slurry? <That is what I use, aerated though to remove the carbon dioxide which definitely reacts with Kalkwasser.> I don't want to have to empty my buffered water and start with new but if I must I guess that's what will have to be done. <I would use it for a water change. It never hurts and you might as well use the water.> By the way my clam is still burping well! <Is this a spawning event? Do take pictures if you can.> Thanks, Jeff <You are welcome. -Steven Pro>

Got the calcium scale blues To the crew, Great job and thanks for all the help. All of you deserve a big hand for all the time you spend helping others. <Thank you kindly!> My question is regarding a white film that covers the inside of my mixing container, heater and, power head between water changes. I use IO salt, RO water (pH 6.8). First, I aerate the RO water then add the salt. After 12-24 hours I test the water for salinity and pH and adjust as necessary. I use Seachem Marine Buffer most of the time since the pH is usually only around 8.0. Once everything is settled, I add a cup or two of tank water and let it age with the heater on and the Hagen 802 power head providing circulation for about a week. After about 24 hours it starts to form a white film that eventually covers everything. If I clean the film off the container and such (has a gritty feel) it turns the water white and eventually just re-coats everything again. <I am guessing you have added too much buffer and caused a precipitation of calcium carbonate by raising alkalinity with the pH.> If I get to near the bottom where the film is heaviest, it flakes off and tends to clog my power head intake. Am I doing something wrong in the way I am mixing the salt? <Just a bit too much buffer. This sounds much like my protocol for mixing saltwater, except for the introduction of old tank water. For a frame of reference, I use about 1/2 teaspoon each of Reef Builder and Marine Buffer per 5 gallons of water.> I have seen this question posted on WWM chat forum, but no one has provided a clear answer. One response was to add magnesium, would this help? <Not likely, but maybe worth testing. Magnesium should be three times the calcium level.> I am struggling with my calcium levels and wondering if this has something to do with my low levels. <Yes, because all your new saltwater's calcium is laying in the bottom of the mixing vat.> I just tested my water and my calcium is 225, pH 8.2 and alk 5.2 mg/L <Yep, your alkalinity is too high.> this is after a 32-gallon water change early this morning (my tank is around 100 gallons total). I forgot to test calcium levels before I made the water change, but the mixed salt tested over 500 for calcium a week ago. Any ideas? <Do take a look at Anthony's fine article here http://www.wetwebmedia.com/calcalkmar.htm -Steven Pro>

Re: White Film I am still a little confused. I test the water after I have added the salt and everything has balanced out, then I add buffer until it tests at 8.3. By doing this am I adding to much buffer? <I would say too much too quickly. Like I said, if you find yourself adding much more than 1/2 teaspoon per five gallons, you are adding too much. I am guessing you are not waiting long enough between small additions to see the change in pH or perhaps your test kit is inaccurate. Regardless, there is not much else the white flake could be besides calcium carbonate precipitate.> This is what is causing my calcium to precipitate out? <Yes, my best guess. -Steven Pro>

Re: Kalkwasser and buffered RO/DI water Hello, I'm hoping to be able to travel and dive the reefs as much as y'all do someday but until then I'll keep searching your brains for info. <Hi Jeff, go for it, although it could be a long search...> I searched your site for the feeding of Sun coral polyps but can't say as I found what I am looking for though. When you say to feed them with finely shredded krill or Mysid or other types of fare, how finely shredded exactly do you mean?  <It means finely shredded *krill*, *and* Mysid shrimp. Does that read better? You shred the krill. The Mysids are can be blended slightly, but they are already much smaller than krill.> Does this mean chopping the already minute Mysid (which is what I'll be trying to use) in a stick type blender until you can't discern the liquid from the shrimp or do you mean to actually shred by hand or cut with a knife or similar into much smaller pieces? I tried puréeing a mixture of Tetra flake food mixed with Reef Plus by Seachem with my stick blender and then squirting gently at the open polyps but I think the mixture may be too fine to do any good. It comes out the consistency of water with no noticeable chunks for the polyps to grab hold of. I also tried this with frozen Mysis shrimp but think again the mixture is too fine to do the polyps any good. I just acquired three pieces of the Sun coral and want to do what I can to make sure they get fed well. <Some corals will like that fine watery food and others with more substance, you will get a little of both with judicious blending.> Also, I think someone wrote in last week about their pH jumping up about .2 when they add Marine buffer but it then falls right back down by as much within a few hours. I lost your answer to that question as to what may be going on but can't find it again. I am having the same problem and don't know what to do to get my pH up and keep it up. <Test carbonate/alkalinity, calcium and magnesium. Low carbonates/alkalinity can allow pH to drop as can low magnesium. High calcium could depress alkalinity and thus pH. You need to test your parameters.>  I have drilled a hole through my window and run air line to a CAP 1200 in my 60 gallon acrylic tank I use as a sump and also the same air line is going to my venturi for my protein skimmer trying to stay away from any CO2 that may be in the house and trying to aerate the tank as much as I can. Should I add another air line to another powerhead in the sump? How much magnesium and strontium is too much to keep the pH in check or can you put too much in? How fast does it deplete in a system? Please, any info would be appreciated. Thanks again, Jeff <Do not add supplements indiscriminately, test for each and add only the recommended dose to raise them to the desired level. My bet is it has nothing to do with how tight your house is and CO2, except at night when pH drops in most tanks. Look at the WetWebMedia sponsors, they have the correct test kits. Craig>

RO/DI Use I am currently resetting up my 125 gallon tank. I am going to be setting it up as a FOWLR tank. I have a 125 main tank, 55 gallon sump tank, and a 38 High refugium sharing the same sump. I am looking to do this right this time from the start. I have never used RO/DI before and would like to take the plunge. <I highly recommend all marine tanks use purified water. You will save time and money over tap water by not having to battle nuisance algae problems.> The tap water in my area is hard and worked for my cichlids, but I don't trust it for a reef or salt setup. My confusion comes when it comes to adding the RO water. I have seen on the FAQ's two opinions. One saying its ok to plumb the RO directly into the tank for auto top offs and other opinions saying its not the best thing to do. <They are both right. I have seen people use their RO water straight out of it for automatic top offs, but it is not the best option. Taking RO water, storing it for a day, aerating it, and perhaps using it with Kalkwasser is the best.> Can you help clear this up? <See above. Hopefully you will understand my explanation.> I don't wanna make a mistake before I even restart this thing. What options do I have here? Any help clearing this up would be awesome. Thanks, Tim Turner of Reading, PA <You are welcome. -Steven Pro>

Buffering Top Off Water I buffer my top off water after aerating for a day. If I test for KH/Alkalinity, what should my results be before I use the top off water? <Ugh, what?> Should I be getting these results immediately after adding the buffer? <I would wait until the next day. You are looking for trends here, not immediate changes.> I don't want to use too much. I am using Seachem Reef Builder. <I would add the same amount every other day, testing on the odd days for one week. Then look back at your records and note the trend. You will then know if you must adjust up or down. Repeat this procedure for a few weeks until you get a feel for your tank's needs. Then just double check every couple of months as things grow, you add new corals, etc. your tank's demands will change.> Thanks <You are welcome. -Steven Pro>

Dechlor With R/O? Hey guys, seems I read your site and pop in a question daily! Always tons of reading to do here. <Ahh- but what a cool way to spend the evening, huh? Scott F. here today> I always used SeaChem's "Prime" in my tap water before I purchased my Kent 3 stage R/O (24g per day model, TGF or something like that). Can I toss the Prime now, or should I still use it? Thanks again..... <A good R/O unit should be able to remove chlorine and other impurities from tapwater...so I'd save the money for other things, like those cool ceramic signs that say "No Fishing", or the "Bubbling Action Skeleton"...Seriously- I don't use these products with RO/DI systems. Hope this helps! Regards, Scott F.>

Buffering Hey gang, just picked up my Kent 3 stage r/o 24g/D (glad I can still get them wholesale, didn't realize what a deal $200 Canadian is till I looked around), can't wait to see an end to this flipping hair algae.  When I was using tap water (ph 7.6 range) in my 130g FOWLR tank, in my top off water I would use a half tablespoon of SeaBuffer per 5 g, I don't test ph and alk, as I am always in the 8.2 range with my tap and salt mix (IO, Kent, Tropic Marin, whichever the trans shipper has), alls well with fish and coralline on my 200-220 pounds of live rock, now with this r/o I know it knocks all levels down and I need to change my lazy ways, how much SeaBuffer should I add to this water? <Testing will confirm how much you need. Do please see the FAQ's regarding mixing new seawater suing purified water.> Is it now needed along with my salt mix, or will salt buffer to the 8.2 usually even with r/o (ph ?)?, is there a usual amount of SeaBuffer to add to each 5g of r/o for top off (no salt), or do I really need to test as there is such a great many variables? No corals and the likes guys, and ol' riot is lazy, but I do follow oh gods of fishland here at WWM, so tell me what I gotta do, one last thing, this PSI rating (65) for the unit, who knows what the PSI of my tap is, does that effect the quality of the water, or just how long it takes to make? <How long it takes.> I have the unit sitting inside a laundry tub just below the tap, it is to run for 12 hours or so before use, and so far I am getting a good flow out of the waste tube (might just have that flow into my washing machine so Anthony doesn't think it too much of a waste ;) , and little drops from the good tube, sound normal? <It should produce about 1 gallon per 4 gallon of waste water. You can measure both with a cup to see.> thanks for your time as always guys, have a great day!......riot.... <In the future, please use capitalization and spacing when appropriate. We archive all the Q&A's and it is best for other readers if these are in proper English. Your email program should come with a spell checker to make things easier for you. -Steven Pro> <<Yes, this would definitely be appreciated! Barb-->>

Macroalgae and Water Pre-Treatment Good evening! <Hello! Scott F. here tonight> Have just 2 quick (I think!) questions for you this time around.  I recently emailed you regarding changing my "nitrate factory" (sump with bioballs) over to a macroalgae filter, you recommended Chaetomorpha or Ulva vs. Caulerpa. Problem is, I have only found mention of the names of these macroalgae; never any pictures (for identification) or locations where I might purchase them. <Chaetomorpha is also called "Spaghetti Macroalgae".  It really does look like spaghetti or a kitchen scrub pad! A good commercial source of this algae is Inland Aquatics. Ulva can be purchased from Indo Pacific Sea Farms. There are other commercial sources for these and other macroalgae; it will take a bit of searching. Alternatively, you may want to post an inquiry on WetWebMedia.com's chat forum; in all likelihood, there are other hobbyists out there who have these macroalgae available for sale/trade.> I searched the site for several hours this week.........(It's a guy thing ya know, never ask for directions!!  Well, I'm convinced........I'm lost!) Any help would be greatly appreciated. <You are right- there is not a tremendous amount of hobbyist-related stuff on the internet regarding this particular species. Much of the husbandry information that you'll find on this macroalgae is from fellow hobbyists, so do use the chat forum on our site or more information.> Also, in scanning through all the FAQ's, I caught something about watching your pH, and alkalinity if you use "raw" R/O water for tank top offs.  Can you point me to more information as to what I should be adding to my R/O water before adding to my tanks? <First, you should always aerate the water before using it; to help drive off the carbonic acid that's usually present in highly purified water. Second, you may want to use an aquarium alkalinity buffer product to help "reconstitute" the water. More on this topic is available on the wetwebmedia.com site, and a further discussion of source water and its treatment is available in Anthony Calfo's "Book of Coral Propagation".> I didn't realize this was a problem, yet probably explains my low PH. <R/O water tends to be very unstable, acidic, and have no hardness, so aerating and buffering the water before using it is a necessary step when using RO water, IMO> Thanks and Happy Holidays!! Doug Edwardsville, IL <And thanks to you, Doug- Good luck in your efforts! Regards, Scott F>

RO/DI Questions Hi guys, I am a few days from purchasing the Typhoon 3 RO/DI from http://www.airwaterice.com/Typhoon%20lll.htm, if you know anything about this model (positive or negative), I would appreciate your input.   <I have no first hand experience nor know anyone with this brand.> I've read that after processing the water through the RO/DI you have to use some sort of supplement to replenish certain essentials that are removed by the RO/DI process. <Correct. Best to read through the articles and FAQ files on treating RO or DI water. My protocol (briefly) is to aerate, heat, mix salt, test pH, alkalinity, and calcium, adjust with additives, and use.> Can you please point me to a vendor where I can find these additives? <Just about any good buffer will work.> Also, any recommendations on a brand name for the additive is appreciated. <I use Seachem's Marine Buffer and Reef Builder.> Thanks, Adam <You are welcome. -Steven Pro>

Distilled water buffer, loose corals Can you recommend an appropriate buffering agent to use with the distilled water?  I started using tap water, which helped with the acidosis, but I checked my carbonate hardness and it is now 50 ppm and my general hardness is up to 100 ppm.  This is a little higher than I would have liked.  Guess I'll just keep using more distilled water and try to maintain with additional tap water.  I just thought if I am going to add anything, it might as well be minerals that the discus can utilize. <I would use baking soda, sodium bicarbonate, "Arm and Hammer", unless there is/was other types of life that require other mineral content> Can you recommend anything to keep my button coral in their place?  My turbo snails keep knocking them off of their rock.   <A bit of epoxy... these are sold in the trade for this purpose. Bob Fenner> Thanks, you guys are great

One more RO/DI question Hi again, <Hello!> I was wondering what the best procedure would be for introducing RO/DI water to an established aquarium.  Should I just begin using it for top off and regular water changes, with no changes to my usual routine; or, should I begin with one or more, larger than normal water changes? <Makes little/no difference. Test the pH and make it match your aquarium and of course...match the temp to that of the aquarium> As per my last email, I have found 'RO Right' and 'Osmo Prep Marine' (both by Kent), are these types of additives necessary? recommended? <Test your pH to see if it matches your tank. If not buffer it up using baking soda or other buffer fluid/powder. I am not familiar with RO Right but if it's a buffer agent (and it should state that on the label) then it will work as well as anything else> Thanks again, <You're more than welcome! David Dowless> Adam

- RO Questions - Hi guys, Bryan here. <Hi, Bryan, JasonC on this end...>1 Have some questions regarding water makeup with RO. <OK.> Read thru F&Q's and would like some help clarifying some things.  OK here goes.  Make up water to add to tank:  I take my RO water and aerate and heat for a day to drive off CO2 and increase dissolved O2. (this next order is where I'm a little confused) Then add my salt mix (Tropic Marin) aerate for a day.  Test for salinity, pH, and ALK, add buffer as needed from the test results. Sound OK? <I would add buffers at this point, before you add the expensive salt. RO water is depleted of minerals and will take them up like a sponge, potentially leaving you with a lower than desired pH. Best to add either baking soda or a commercial buffer like the Seachem product.> Evaporation top-off:  Take RO water, aerate and heat for a day. This is where I'm a little unsure.  Test the water parameters and buffer as according? <I'm not sure you need to heat the top off, unless you add it in bulk quantities.> Set pH and Buffer according to main tank display, right? <Ideally, yes.> Last thing to help me clarify.  In the display tank I'll use ESV 2 part B-Ionic for ALK and calcium.  for top off and make up water I'll probably use SeaChem reef builder.  Do using these 2 different buffers in the water have any adverse affects? <No. The two part additive is a 'system' so that the buffers compliment the calcium additive. The buffering in your top-off is really only making sure the RO doesn't lower the pH of the tank.> Ok last thing for real.  IYO who or what company has the best all around supplements/additives, Mg, Br, Iodide etc... (just wondering, only using if test for and find a need) <I don't have any particular preference, but I do try to stay away from Kent and Mark Weiss products.> Thanks for your help Bryan. <Cheers, J -- >

- RO Questions - Jason, Bryan again, thanks for quick response and great info.  <My pleasure.> You helped clarify things for me about RO water treatment.  I was a little confused about the order of adding buffer and salt.  I had read somewhere to buffer then add salt and then last night read someone from WWM was adding salt then buffer.  Got a little confused.  This is probably a silly question. But when buffering the raw RO water, are you shooting to buffer to the target range for the main display or just adding enough to add some minerals to the water so it doesn't act like a sponge when you add the salt? <The latter, just enough so that the RO doesn't deplete the buffers in the salt.> Thanks again Bryan <Cheers, J -- >

Adding a buffering stage to a water purification system Hello, I have a Kent DI unit that is attached to a float in my sump that automatically replenishes my evaporation water, now this water is not buffered and I suspect it is one reason for my pH staying in the 8.0 to 8.15 range (also run a calcium reactor). I was trying to think of a way to buffer the water without changing my current set up and had a "crazy" idea that I would like to get your opinion on. I was thinking of adding another stage to the DI unit at the end before going to my sump, fill the canister with some  media that would dissolve raising the buffer and pH, if I filled the canister with the same media used in my reactor would this work? << No, it would need to be in solution.  <...Incorrect. RMF> You could add a little Kalkwasser, but I don't know if you could adjust or maintain a certain level with any regularity.  I think you are better off just adding a teaspoon of Kalkwasser every week. >> I know the water is acidic coming from my well and the DI makes it no better << Then your DI and RO stage aren't working.  It should come out neutral. >> so my thoughts are the media would dissolve (just like in my reactor) and therefore buffer my top-off water. Thanks for your time, all comments are appreciated. << Well if is a solid media it won't just dissolve.  Or at least not at a high rate.  I think powdered Kalkwasser is a simple and easy way to go.  Plus for the most part you want your RO/DI unit working without any additional items that affect the water coming out of it. >> Thanks Mike Winston <Blundell>

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

R/O Water <Anthony Calfo in your service whilst Bob is away whistling Dixie> Have ordered a RO unit and have been reading thru F&Q. In yesterdays questions someone asked about RO and made me wonder if I understand correctly. RO water is stripped of hardness and Alkalinity.  <yes...completely de-mineralized if good> So you need to reset the alkalinity and PH w/ s/t like SeaBuffer.  <sort of...but before you do, you must aerate it for 12+ hours to drive off carbonic acid that will waste added buffer (in salt mix or as supplement). AFTER aerating... you should then add a sea buffer to "re-mineralize" it for seawater use as evaporation or to make seawater. It will be more stable as such> Let me go over this and see if it sounds good. Take the fresh RO water, add nothing, set temp and aerate for about 24 hours. Then add (this is where I'm not sure about next step) SeaBuffer (b/f salt?) <yes, before salt> to set the pH and alkalinity to correct level  <doesn't have to be perfect... just close. Near 8.0 would be nice before adding salt> and aerate for another 24 hours.  <just a few hours will be fine> Then add the salt and set the S.G. and let aerate for another day.  <again... a full day is not necessary. Really overnight for first aeration, a few hours for SeaBuffer and another 6-12 hours for salt circulation is fine. 24 hours to properly make seawater is possible. Extra aeration may not help much> Let me know if I need to do s/t different. Thanks Bryan. <nope...short and sweet my friend. Anthony>

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

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

RO Preparation I heard you have not been getting your WetWebMedia mail so I am going to try this (hope it is ok): Anyway I know you are suppose to aerate the RO water for at least 12 hours before use but how much aeration is required. I prepare 5 gallons at a time with a Power Sweep 212. Not a lot of bubbles are produced by the powerhead. Is this ok? Shaun Nelson <Fine if you aim the powerhead up in some fashion to create a lot of surface turbulence and therefore gas exchange. -Steven Pro>

Top-Off Water pH Problems Sorry to bother you with another question again so soon, but I am at a loss as to what to do about my top-off water's pH. <No problem.> I purchase RO water from my LFS. I've tried Kent's Osmo-Prep as well as Seachem's Marine Buffer, but what keeps happening is that the pH is fine as soon as I add it to the RO water, but by the next day the water is highly acidic and below my pH test scale. I aerate the water as soon as I bring it home and keep it aerated as I use it throughout the week, but it will not maintain an acceptable pH. What I'm trying to do is have freshwater constantly aerated and pH adjusted so that I can just pour it in the tank once or twice a day to make up for evaporation. Can you recommend a way to do this? Or do I need to pH adjust the top-off water each and every time I add it? <You should not need to keep adding buffers everyday. Perhaps you are just testing too quickly and the RO water has not had enough time to mix with your buffers. I use Seachem Reef Builder and Marine Buffer, about 1/2 teaspoon of each for every five gallons, and have not had a problem.> Thanks so much again for your assistance! Karen <You are welcome. -Steven Pro>

Top-Off Water pH Problems Steven, Thank you for your reply a couple of days ago, but I am still having the same problem. I aerate the RO water for 24 hours with an airstone, then add my buffer, mix it, and continue to aerate. But the pH still plunges for me. This morning, for instance, I added my buffer and tested it 90 minutes later. It was at 8.4. But now several hours later I tested it again (after being continuously aerated) and it is now down to 7.8 again! It keeps driving my main tank's pH down whenever I top it off. I've tried Kent's Osmo-Prep, Seachem's Marine Buffer, and both together. What am I missing? Please advise. <I was talking to Anthony about your problem today and he suggested running the same little experiment that you outlined above, but instead open a window in that room. There are strange instances of people living in well insulated homes having increased levels of CO2. See if that does not correct your plunging pH. If not follow-up and we can discuss this further.> Thanks again, Karen <You are welcome. -Steven Pro>

Top-Off Water pH Problems III Steven, As always, thanks for your prompt response. I don't believe increased CO2 in our house is the issue -- our house is not well-insulated, the doors are constantly opened with kids and dogs going in and out, and my top-off water is aerated by a drafty fireplace. <Okay> HOWEVER, I think you may have pointed me in the right direction in that the water isn't getting aerated well enough. I kept thinking that it was something I was doing wrong with the additives, but instead I think it may be a combination of my cheap air pump running through too much tubing. I was using the same 8' of tubing that I use when I aerate water in my large trash can for water changes, but I have now cut the tube down to 4' for top-off aeration and I also plan on upgrading my cheapie air pump in the next couple of days. Could you possibly recommend a good-quality air pump that doesn't cost an arm and a leg? <My all time favorite was the Tetra Luft pump. Discontinued by Tetra, but Coralife is selling them now. They are one of the most powerful pumps out there, but far from the most expensive (not cheap mind you, but more bang for your buck than others). I also like the Tetra Tec Deep Water pumps, not the regular ones.> What should I be looking for in terms of PSI and cc/min. for aerating 5-10 gallons at a time? <This is a pretty small amount of water. Most air pumps do not tell you PSI or anything. Many just say good for up to so & so gallons. I would get something rated for at least 25 gallons.> Does any particular airstone do a better job at aeration (wood, glass, ceramic)? <Glass or ceramic. While on the subject, I use a Mag-Drive 500 in a 50 gallon plastic drum for holding my deionized water. I place the pump in the bottom aimed straight up. It creates a lot of turnover, surface agitation, and heats the water.> Lastly, since my pH kept going down in my main tank due to the top-off water, I had to buffer my main tank with Seachem's Marine Buffer a few times over the last 2-3 weeks. I'm kind of afraid to ask, but did I cause any harm by doing it this frequently? <Possible> Could calcium or alkalinity have shot up to dangerous levels? <Perhaps alkalinity and then had an effect on calcium levels.> I don't have calcium or alkalinity test kits (yet). <Yet is the important word.> You guys are SO helpful, and I am so grateful for your assistance and information. -Karen <You are welcome. -Steven Pro>

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

RO and Kalk Hi, I'm going to do more research on the Wet Web site. I knew I needed lighting (probably VHO)  <many choices among lighting. Decide your inverts first for the long run and then a lighting schemes to suit them. If you have your eyes on SPS and clams in the 2 year picture... you may need MH> but you also recommended a buffer for my R/O water top-ups (nightly) and a new skimmer.  <actually I recommend buffer for all demineralized water, but not so much for nightly dosing.... Kalkwasser imported at night is best (because it tempers the pH drop at night)... while buffer is best imported by day when the lights are on and pH is highest (buffer will not raise any higher like Kalkwasser will)> Could you please give me your preferences on both?  <hmmm... if you care, please do read my strong opinions and reasoning on the disfavor of RO units (wasting water). Do consider for upgrades in the future to DI units.> By the way Bob's book is on the way...can't wait to get it.  <a fantastic read! One of the best works on aquarium science to date IMO> Thanks again Anthony, Ken. <best regards, my friend>

RO water storage Dear Mr. Fenner: I have a quick simple question. Should I aerate my RO water storage? <Yes, for sure> I would use water from this storage to top off, make Kalk solution, and any water changes necessary. Also should I use a RO water conditioner before adding to the tank (top off), Kalk mix, and mixing salt (water changes)? Thanks <Please read here: http://www.wetwebmedia.com/water4maruse.htm and the links, FAQs listed at top of this article for more detail, input. Bob Fenner> Best Regards, Jim in Florida

Re: RO water storage Bob: Again I must thank you for all your input. Buffering my top off water will be new to me. What buffering agent should I use in the top off water & what numbers do I shoot for? <Simple sodium bicarb. mostly. Please see the WWM site re these questions (and more that I/we can/do anticipate), perhaps starting here: http://www.wetwebmedia.com/marphalk.htm and the FAQs files beyond> Also note I use NatuReef's products. When I add my top off water every day I also add their ALK & Hard plus (their form of liquid buffer) a cap full of each. That seems to keep my ALK stable with everything else I do. Will buffering the top off water throw this off? Thanks for the expertise! Jim <S/b fine. Bob Fenner> FYI: My test results of tank as of 1145AM ALK 10.5dKh Total Hard 6.31%CaCO3 Ca 460mg/liter <Looks good>

RO water storage Bob: Thanks for taking the time to answer my question so quickly. I just need a little more clarification. Should I just aerate the top off water, or buffer it also?  <Both> Should I only buffer if I am mixing salt for a water change? I use Tropic Marin salt exclusively. Jim <Mmm, the best synthetic salt mix on the market... You do measure alkalinity I take it... if this is being supported sufficiently by the water changes, I would not buffer it further. Shoot for a dKH of about 12, no more than 15. Bob Fenner>

Re: RO water storage Bob: One other thing...FYI:  I dose the Kalk at night 10oz over a 10hr period. Then I add top off water during the day when I get up). Is this ok? Jim <About the best protocol. This is what I would do if using calcium hydroxide (we use reactors, and occasionally Kalk, CaCl2). Bob Fenner>

RO Water Top off & Calcium Reactors Bob, <Steven Pro in this morning.> I top off my tank with water directly from my RO unit on an automatic system utilizing a solenoid. Do you have any advice on how to keep up with buffering as adding it has created spikes due to the automatic replenishing of fresh water and the fact that I only buffer weekly. Any advice. <This is really not a good idea. While it maybe convenient, it is always best to hold and aerate any demineralized water for 24 hours. This maximized dissolved oxygen and off gases excess CO2. It is the CO2 that is messing around with your alkalinity.> I also was considering purchasing a calcium reactor from Lifereef. Have you heard of their products. Any comments. <Have not used there products. Do solicit comments form other hobbyists on the message boards. I know of two very friendly boards; ours at http://wetwebfotos.com/talk/index.jsp and a friend's at http://www.thesea.org/forum/default.asp You may also wish to inquire at both reefs.org and ReefCentral.> Thanks, Liz <You are welcome. -Steven Pro>

Buffers WWM Guys, I am topping off and doing changes with RO water. Also, I use B-Ionic two-part mix for calcium supplementation and Instant Ocean to keep SG at 1.025, pH is 8.4. How would you recommend I buffer my RO water? I tried using baking soda and it precipitated out when I added Instant Ocean. Why did this occur? <You added too much buffer. The salt mix has buffering compounds, too, and with what you put in first, the pH got too high and drove the calcium to precipitate out of solution. <<Mmm. No, not high pH, just high/er alkalinity. RMF>> I prefer to buffer my water after adding the salt. I aerate and heat the water first for a day. The add the salt mix and mix for another day. Lastly, I test the salt water for salinity, pH, and alkalinity and buffer according to the results of my tests. If you wish to buffer before adding the salt, only add enough buffering compounds to bring your raw RO water to a neutral pH.> I am interested in raising my calcium to 450 from 350 ppm. I have good coralline growth and tolerable slow growth in my SPS/LPS corals. Perhaps I could cut back on the B-ionic I use if I buffered my water? <Perhaps, on use a calcium reactor to really accelerate growth. That is, if you have a large enough tank. I would find it hard to justify the expense if you told me you had a 29 gallon mini-reef. If 75 gallons or more, the money you save on supplements will outweigh the initial cost in a few years.> What should I use for this? <I think Seachem products, Marine Buffer and Reef Builder, but there are other fine products. Aquarium Systems SeaBuffer is also nice. -Steven Pro>

Measuring pH in R/O water Hi, <cheers> Having recently purchased a 3 stage r/o unit, I was surprised to hear that neither aquarium hobby quality pH test kits nor a pinpoint ph meter are sensitive enough to accurately measure a drop in pH in the treated water.  <huh? I don't follow or agree> Allegedly, testing the r/o water would yield essentially the same pH reading as the tap water.  <ahhh... somebody is either insane or trying to sell you an expensive piece of test equipment... heehee. What is it you are trying to do my friend? Test the R/O effluent? If so... are you trying to (improperly) test it before aerating it (driving off the carbonic acid)? In which case the pH will likely be too low to register on some liquid reagent test kits... but still show up accurately on a pH monitor. Heck... they calibrate those instruments with solutions at 4.0 (7.0 and higher too)!!! Are you saying your pH is lower than 4.0... if so, you have bigger problems than test kit accuracy. Ha! I know... just kidding. Still... catch my drift?>  I've used three popular pH testers, and this seems to be the case. I was assured that the r/o water in fact would have a lowered pH (around 7.0), but that I couldn't measure this drop.  <whoever is telling you this I believe is very mistaken... the process is not so absolute or reliable to support such a statement for SO many reasons. Quality of source water to begin with, type of RO membrane, age of membrane, pressure of water forced through it, etc.> I want to start a discus tank, and would feel reluctant to do so if I couldn't take accurate pH measurements. I would appreciate your thoughts on this matter, and thanks, as always; <good heavens, my friend. Fire whoever has given you that advice and have a beer. Relax bud :) pH testing equipment is reliable and nearly a science. Avoid hobby reagent kits for better readings and know that most monitors from $50-$250 are quite similar and relatively to very reliable... at least for our purposes. They will read accurately if calibrated correctly right down to a pH of 4.0 at which point your discus have all leapt from the tank due to acidosis fright/shock. A $100 pH meter is a fine investment... do enjoy the hobby. kindly, Anthony> Bill Roman

Re: Measuring pH in R/O water Hi, Thanks for your prompt, and humorous response.  <I'm good for something <smile>> To clarify, I recently purchased a Spectrapure, 3 stage Ro system, because your site has spoken well of the brand.  <very fine> When I use Wardley's ph indicator and Aquarium Pharmaceuticals pH indicator to test the tap water <hmmm... I do not personally hold Wardley liquids test kits in high regard... and the while I like the Aqua Pharm dry tabs reasonably well, I do not care for their liquid test kits much better than Wardley's. As a rule... liquid test kits are easily corrupted and have short life spans. When possible... use dry reagents if not digital equipment> And the ro water not the waste) I get the same 8.6 reading.  <highly doubtful... an inaccurate reading. Are these test kits labeled marine use? Have you tested your raw source water... it will be higher... and with such high readings... it's as if bleach or lime are pouring from your spigot>  I just used AquaLabs I test strip and got a 7.0 reading on the RO water. It seems the test strips are doing a better job than the liquid agents in detecting a pH drop.  <wow... test strips... I wouldn't take them for free and I sure as heck wouldn't trust livestock to their readings. Very crude readings> Did I understand you correctly that the hobby quality test kits tend to be less accurate?  <actually some are quite good... dry Aquarium Systems brand kits are affordable and generally quite accurate IMO> I know you guys like Salifert test kits, so I recently purchased some for my salt water set-up. I read your site a lot, and also, as it suggests purchased a pinpoint monitor tester, which is still new in the box but not for long) as I'm still in the process of accumulating gear, and advice.  <yes... enjoy and keep learning> You did convince me not to worry about being able to measure the pH of the ro water. Thanks, Bill <whoa, bud... not my message at all. raw de-mineralized RO water is dangerous... you do want to know where you stand with it. You simply need to learn not to knee jerk react on any piece of advice from the LFS, me or anybody (like assuming that because the test strips gave the most believable reading that they must be accurate/reliable... quite the contrary). The hobby need not be so complicated... research your products and protocols in advance and enjoy the hobby. (e.g.- A check on the message boards regarding the liquid test kits or the test strips would have spared you from buying them with an intelligent consensus). Best regards, Anthony>

Water Top-Off Good day everyone, <And you too!> It has been a while since I wrote last. Once again, just a short question. I, like so many others, has been getting tired of continually adding freshwater to my 90 gallon reef tank due to evaporation. I followed one of your links and found some DIY plans for a 5 gallon bottle that replaces the water automatically, and it works fantastic. My question is this - up until now, I had been aerating and heating my top off water. Of course I can't do that now. <You should still aerate and heat prior to filling the 5 gallon bottle.> Is this OK in your opinion? <Not really. You do not want to continuously dose your tank with low pH, carbon dioxide infused water.> I go thru about 5 gallons of water in three days. Thanks as always. John <If you aerate the water and then fill the jug with this "treated" RO water, you should be just fine. -Steven Pro>

RO Water Hi Bob - <Anthony Calfo in his stead while he travels Indonesia slapping bumper stickers on Pachyderm's rumps that say "Bob was here"> Love your incredibly informative website!  <Danke> I've seen much info on mixing RO water with tap to balance tap water, but not much about bringing RO water into habitable quality.  <it really is the same thing, good sir... re-mineralizing is re-mineralizing whether executed with dry reagents are delivered in hardened water> I should also tell you - I live in the middle of nowhere and the best accessible fish store is Wal-Mart (pretty bad!)  <yeowsa!> so don't really have a local outlet for specialized assistance like this. <gotcha> First - the vitals - I have a brand new 46 gallon tank - no fish in it as yet, it's got another week to 10 days to cycle. I've kept a 20 gal community tank with primarily tetras for 25+ years. I set up the new tank with RO water 5 days ago. I have a Skilter power filter and two airstones for aeration. No live plants either. I like tetras for my tank (pretty, easy care) but might need to adjust my intended occupants depending on what I can accomplish with the water. <exactly... and using a simple buffer solution with a test kit to achieve these goals. Baking soda and aeration alone might do the trick for softer water species> I've used Aqualab I test strips to determine that the RO water is very soft (like 0 ppm),  <IMO the test strips are patently unreliable. I wouldn't take them for free, although I do believe that you have succeeded in achieving pure water. Just don't trust the strips for the fine tuning as you re-mineralize> neutral pH, and high alkalinity.  <OK... here we have a problem. How do you distinguish between alkalinity and hardness... because having stated that pH is neutral (OK)... the aforementioned both sound like incongruous references to the same/similar parameter.> To the new tank, I've mixed in a half gallon of the filtered waste RO water to add a bit of hardness and the minerals which are stripped out - brought GH to about 50ppm, reduced the kH some but still is very high - estimate 450ppm, and exceedingly high Ph (like 8.4+) which doesn't seem to respond to pH down.  <indeed high... unbelievably high unless your tap water is so hard that you can chew it. Do consider that the test strips may not be accurate> I don't have a master test kit and plan to get one this week, so don't have other test values to share at this point.  <ahhh...> Source water for RO is a well with borderline quality - extremely hard (65+ grains), much dissolved calcium and minerals, very low pH, etc. I do have a full lab test on the well water. <K> I am concerned about my RO water being "too" pure,  <agreed> but am unsure what is the best approach to stability.  <perhaps just less tap water mixed in as governed by a more accurate measure of hardness> I have great difficulty dropping the pH on both tanks and use massive amounts of pH down.  <indeed not ideal and all rather temporary> I tried adding some baking soda to the new tank to offer some carbonate buffering, and as expected the pH went up further.  I also put in a couple pieces of coral to add some KH.  <only works below pH 7.6 with such calcite> I suspect that I have zero buffering capability, thus the pH is out of whack and stays there. I have used some EasyBalance to try to bring things in line, but still not there yet. I am considering whether a calcium supplement would be useful to add buffering, even though I'm not looking at a reef tank. I am also looking at buying Pond pH down, because I need so much of it, even though it is difficult to reduce the additive quantities needed for a tank. <way too many chemicals overall... should simply need pure RO to start and controlled remineralization (tap water or buffer). Peat filter for natural aci8ds if necessary> So - my question (yes, there really is some) - what products would you suggest to assist in obtaining and maintaining a balanced environment?  <as per above especially if looking at soft water fishes (tetras, cichlids)> Is there any advice you can offer for "unpurifying" RO water?  <do consider peat plates or pellets for in tank long term assistance> I've done the new tank fish kill thing way too often in the past and would like to think I've learned from past mistakes and will get things in order before I buy any fish to throw in the new tank. I am also wondering if I should stay with the livebearer fish communities for their tolerance to the higher pH.  <its really not a terrible idea... making lemonade out of lemons :) Do consider the colorful African cichlids too> Should I consider live plants to help fix nitrogen and buffer pH? <not satisfactory IMO> Thanks for your assistance. Jeannette Hook <best regards, Anthony>

Re: RO/DI Recommendation Thanks again Steve. <You are welcome.> Today I purchased all I need for the Durso Standpipe. You have been a great help, can I run a few things by you please? <Fire away.> My tank is 125 gallon All Glass with two overflows with WMD 40 RLXT Iwaki pump and Eco System 3612 filer for a reef tank. 1) The Durso drawing has the stand pipe (I purchased 1 1/4") going into a reducer bushing (1 1/4" to 1") going into a 1" threaded male adapter. I found a single fitting that is a 1 1/4" slip bushing reducer that ends with a 1" threaded male (thus combining the reducer bushing and 1" threaded male adapter into 1 single fitting). Is this better or is there a reason for the 2 separate fittings? <This should work fine.> 2) What do you recommend I use at the ends of the 90 degree elbow that returns water into the tank? <That modular piping is nice. It allows for easy adjustment of the water flow. You should be able to find it at any aquarium online store.> 3) Do you recommend I add any power heads to the tank and where should I locate? <My specs show your Iwaki running at about 1200 gph at 4 feet of head pressure. That should be ok for most applications. You may want to distribute this flow around to several different ports.> What about an self rotating? <No> 4) I will use RO water to start (SpectraPure CSP-60). What salt brand do you like? <I like Aquarium Systems Instant Ocean and Reef Crystals, but I have not tried everything out there.> Any other additives to start? <Primarily you want to maintain calcium and alkalinity levels.> 5) Plumbing - I plan to use two 1" flex PVC hoses going into the filter. Out of the filter is a ball value (can't find PVC gate) <In this case, the ball valve is fine. It is merely a shutoff valve, no fine control.> then PVC Union then the pump. Straight up from the pump is a 1" PVC pipe, PVC Union then a T, then across to each end of the tank with a 90 degree up into bulkheads. Sounds good? <Sounds fine> Anything you would do better? <No, pretty much how I would have done it.> Thanks again, Steve <You are welcome. -Steven Pro>

Cloudy RO Seawater I just purchased an RO/DI unit from AquaFX. Installed it last weekend and made my first 10 gallons of RO water for a water change. Everything was going well. I put a powerhead and heater into the container and let it aerate overnight. In the morning I put some Proper pH 8.2 into the water to bring the pH up. A couple of hours later I added my Instant Ocean. When I came home from work the water was cloudy and I couldn't figure out why. I searched around on WWM and thought that I was doing something wrong. So I dumped that water and tried again. This time I made 10 Gallons of RO. I let it heat up and aerate with a RIO Powerhead for 24 hours. I checked the pH and it was lower than my test kit could read (7.2). I checked the alkalinity and it read low. I received conflicting answers on your site as to what to do next. Add buffer or add salt. I figured that since I added buffer first last time and failed, I would add the salt this time. Added the salt and let it continue to aerate and heat. Woke up in the morning after 8 hours of aeration and the water was cloudy again! The salinity was at 1.020. I don't know what I am doing wrong. Any ideas?  <You state you aerated with a powerhead. Did you actually use the aeration feature, the air line above water line? You probably have excess CO2 in the water which is causing your low pH along with your low alk. I would add something like SeaChem's Reef Builder to your fresh mix to bring the ph to the desired level. As for the cloudy water don't know what to tell you. I'm thinking it may be this Proper PH you are putting in, not familiar with the product, but some ph boosters do cloud the water for a while. James (Salty Dog)><<Mix the saltwater up first... then measure for pH/Alkalinity, and adjust... RMF>>

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

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

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

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

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

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

RO Water Hi Anthony, What do you use to buffer the RO water, and what test is used?  -R. Gibson <Aquarium Systems SeaBuffer and Seachem's Reef Builder and Marine Buffer are all good products. The easiest thing to do is aerate and heat your water first. Then add and mix your salt. At that point, test pH and alkalinity and adjust as needed with any of the above products. -Steven Pro>
RO Water II
Steven Pro, Do you buffer the water that you add to your sump due to evaporation. -R. Gibson <No, but I do aerate the water and mix it with Kalkwasser. -Steven Pro>

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

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

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