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FAQs on pH, Alkalinity, Acidity: Products

Related Articles: pH, alkalinity, In praise of hard water; How hard, alkaline water can be a blessing in disguise by Neale Monks, Treating Tap Water, A practical approach to freshwater aquarium water chemistry by Neale Monks, The Soft Water Aquarium: Risks and Benefits by Neale Monks, Freshwater Maintenance, Treating Tap water for Aquarium Use

Related FAQs: pH, Alkalinity, Acidity 1, pH, Alkalinity, Acidity 2, pH, Alkalinity 3, pH, Alkalinity 4 & FAQs on: FW pH/Alkalinity Science, pH/Alkalinity Measure, pH/Alkalinity Adjustment, pH/Alkalinity Anomalies/Fixing, & Water Hardness, Freshwater Aquarium Water Quality, Treating Tap Water for Aquarium Use, Freshwater Algae Control, Algae Control, Foods, Feeding, Aquatic Nutrition, Disease

For some fishes... pH, alkalinity is important to measure, perhaps adjust... particularly if reproducing

Water Chemistry Question    7/15/17
Just the prelims; this is Renee from Idaho (human remains place), uses RO water, Equilibrium, and baking soda to keep my kH where it needs to be to keep my pH stable which is working beautifully). As the weather heats up, I am losing more and more water to evaporation. According to the instructions on my bottle of Equilibrium, I am NOT to add Equilibrium to water I am replacing due to evaporation - so I don't.
But what about baking soda? It's a chemical compound composed of sodium ions and bicarbonate ions (I'm doing my homework :)), but do those ions compose a mineral or not AND as such, will it evaporate with the water or not?
<The Sodium stays, the bicarbonate can be (is) used up by reductive events>
Things are going along so well, everyone (fishy) is doing terrific and I don't want to screw things up.
<I would get/use a combination carbonate and bicarbonate product... and utilize this via the new/water change water (pre-mixed). Am partial to the SeaChem line here. Bob Fenner>
*Renee *
Re: Water Chemistry Question    7/15/17

Do you have a suggestion (or are you allowed to suggest) which Seachem product?
<Oh, sure: http://www.seachem.com/marine-buffer.php
Re: Water Chemistry Question    7/16/17
Ok, thanks.
<Renee... this is a saltwater system? If not do experiment with the amount of product used (in the change out water). Bob Fenner>
Re: Water Chemistry Question    7/16/17

No, it's freshwater with only scaleless species.
<Ah, we're back to sodium bicarbonate then. Added to the change water. B>
Re: Water Chemistry Question    7/16/17

But what about the water I replace from evaporation? The directions from Seachem say not to add Equiibrium, should I still add baking soda?
<Place/mix all additives in the new/change-out water. B>

Thank you, Betta recovery      12/4/16
No questions or cries for help today, just a thank you. Thanks to your site, and your responses to my emails, I know so much more about Betta care today than when I rescued that first Betta from a bridal shower centerpiece about 5 months ago. You, and Bob Fenner’s book, are the best resources I’ve found for learning how to keep a Betta. While the first two Bettas didn’t survive - one because he was too damaged when I got him, the other because I forgot I was using a domestic water softener - I think that I am now all set to enjoy our new Betta for a long time. Our Betta, Ting Krit, and I thank you. Here’s the happy little guy in his heated, filtered, treated RO water, stable pH, 0 ammonia and nitrite, low nitrate tank:
<Looks a nice fish in a nice tank! Glad you're enjoying your new pet, and it's lovely hearing how things turn out, so thanks for sharing. Cheers, Neale.>

No rush question - pH slowly rising in Betta tank      12/18/16
After much - and much appreciated - help from you, I put my new Betta, Ting Krit into his 5-gallon heated, biologically filtered (well cycled) aquarium. He went in 12/1. That day, pH was 6.9, temperature stable at about 77, ammonia reading 0; nitrite 0; and nitrate between 10ppm and 20 ppm. GH tested about 125.3 ppm (which I think is OK), but my KH tested only 17.9 to 35.8 ppm with API drop test. The water is RO, treated with SeaChem Replenish and a couple of Catappa leaves in the aquarium when Ting Krit went in. Readings have stayed stable except a slowly rising pH. (I have not tested GH and KH again.) The pH had been very stable for about 10 days before I added Ting Krit. On 12/3, I added a Brazilian pennywort plant to give him some shade. Since then, it has been a slow rise. Never more than 0.1 in 24 hours. I have changed 25-30% of the water twice now (weekly changes), using a slightly (0.2) lower pH water for the change. I have gradually added more and more Catappa leaves because, before Ting Krit, the leaves had a noticeable effect on the pH, gradually dropping it. With the water changes and Catappa leaves, the pH change has been about 0.2 per week. So, it was up to 7.3 when I did his water change on Thursday after 2 weeks. The water change dropped it to 7.2. Yesterday it was 7.3. Today, it was up to 7.4. I realize that stable pH is the most important thing - and these changes are slow. But, if it just keeps rising, I’m concerned I will have a problem eventually. I just added 2 more Catappa leaves (I’d never added more than 1 before), and hope I will be able to stabilize the pH with that gentle method. (I will check pH a couple of more times today to make sure I didn’t overshoot.) What truly mystifies me is why the pH has now started rising after being stable in the 6.8 to 7.0 range for an extended period before adding Ting Krit and the pennywort. And, I want to stop the steady rise before it becomes a problem. Thank you in advance for your help. A picture of Ting Krit - who is very active and apparently happy.
<Do try this: leave the next water change for 24 hours after you draw water from the tap. If you can, aerate the water for an hour or two before use. Why? Because tap water can contain a lot of dissolved CO2, and as the CO2 evaporates (or gets used by plants) the acidity lessens (dissolved CO2 = carbonic acid). This allows pH to rise. Alternatively, you could use a proprietary buffer (I'd go for something neutral) and see if that 'fixes' the pH between water changes. But if all else fails, if this chap is happy -- and it sounds like he is -- I'd simply adopt a "little, but often" approach to water changes, changing 10% every day or two, and simply allowing these frequent water changes to inhibit any severe pH changes. Hope this helps, Neale.>


Re: No rush question - pH slowly rising in Betta tank      12/18/16
I pour the RO water into a gallon bowl and let it stand for a week or two before I do use it for water change. That gives me time to add API pH Up (always necessary on the RO water) to get it at least in the 6.8 to 7.0 range.
<Understood. So, if your pH still isn't stable, you need more buffering. I'd probably be adding sodium bicarbonate, just the tiniest amount at first, maybe one-tenth teaspoon per US gallon. See how well that works for a week; if necessary, increase by one-tenth teaspoon amounts per gallon over successive weeks.>
So, no tap wager with dissolved CO2. (Had that problem before. Had to stop using any tap water because of home water softener.) When you say proprietary buffer, what are you suggesting? Last exchange I had with Bob before I added Ting Krit - when I was worried about the KH being low and maybe creating risk of pH swings - he suggested a tiny bit of baking soda if I saw drastic changes in my daily log of pH levels - or the frequent small changes you suggest.
<I would concur with either bit of advice here.>
Sounds like changing out some water every could of days might be the best solution, but we leave for a 2 week trip in a month and I worry about the fish-sitter being faithful to the changes.
<Your main problem is overfeeding. Fish can go without food for two weeks, no problems. But to be kind, the safest approach is to put tiny amounts in paper envelopes or sealable plastic tubs (the kind daily medication can be put into work great) then hide all the rest of the food. Leave enough meals for 3-4 meals across your 2 week absence. You'll be pleasantly surprised that your tank will be clean, your fish alive, and your fish-sitter without a sad face when you get home!>
Guess I’ll just have to convince her that this is real easy - and leave plenty of prepared water. Elaine
<Feed minimally, and she can skip water changes for two weeks. Unless she's a fishkeeper herself, she's likely to make a mess. Cheers, Neale.>

Re: No rush question - pH slowly rising in Betta tank      6/20/16
Thank you very much. I feel better about our Betta's survival chances during our trip after your advice about feeding. Ting Krit is a complete pig, like most healthy, happy Bettas, I guess (although so far he will only eat pellets; turns his nose up at the brine shrimp treat I tried to give him). I will make sure he is not overfed in our absence.
The tank is well cycled for almost 4 months and completely stable on everything except that niggling pH rise so it should hold for our 2-week trip in the absence of overfeeding based on the information you provided. I will start slowly adding the sodium bicarbonate this week and see if I can stabilize the tank’s pH before we leave. I checked GH and KH this morning - GH had risen slightly and KH had fallen slightly.
<If KH drops, that means there's acidification using it up. That the GH has increased would support that, implying new salts are being created.>
Looks like time for some additional buffers.
<Seems so.>
As always, WetWebMedia Crew has helped me with the information I needed. Thanks, Neale, to you and the rest of the crew for all the assistance you provide to us fish lovers without as much knowledge as you. Elaine
<Glad to help, and good luck! Neale.>

Re: No rush question - pH slowly rising in Betta tank - EEK, big rise after sodium bicarbonate treatment     12/24/16
After our last exchange about the slowly rising pH in my aquarium (with very low KH reading), I decided to follow your suggestion and add the sodium bicarbonate - in the form of baking soda - to the aquarium to increase the KH. I didn’t want to just dump it into the aquarium without knowing what would happen, so I dissolved enough for my 5.5-gallon tank in a 1-gallon “water change” container first.
I put in 1/2 teaspoon - the 1/10 teaspoon per gallon you had suggested since my tank actually holds about 5 gallons.
<No. Don't do it this way. Add only enough for the water being changed. Not the whole tank. So if you're changing 1 gallon, add enough for 1 gallon, i.e., 1/10th a teaspoon.>
The pH immediately went to 8.5.
<It would do. That's a lot of sodium bicarbonate.>
I didn’t want to dump that in the aquarium which was at about 7.4 at the time, so I used API pH down to get it down to 7.4.
<Why not just pour out half the water from the bucket, add fresh, and see what happens to the pH? Sodium bicarbonate is very cheap, and with these tiny amounts, you can experiment.>
Today, I did a water change and added the gallon treated with the baking soda. By today, the pH in the aquarium was up to 7.5. (My aquarium has been steadily rising .2 per week for 3 weeks, never more than .1 in 24 hours.) The gallon I added was reading a steady 7.4 for 2 days so I thought this would work. I kept a close eye on my Betta and he seemed his normal active, healthy self (always wanting to be fed and building a nice bubble nest). Tonight after I fed him, I did my normal check on pH. It read 8.4. I retested to make sure it wasn’t a bad reading and got 8.3. I double checked my meter by using the API drop test for pH and it was consistent with the meter reading - at least above the 7.6 that is the top of the API chart. Uh oh. Big pH increase in the 7 hours between 2 pm and 9 pm. I was frantic.
<I would be, too.>
I know that fluctuations, not absolute reading is the biggest problem, so I didn’t want to do anything to cause another drastic change. I did another water change with another gallon which had been sitting for several days at 7.4. (This last change had 1/10 teaspoon of baking soda in it.) I figured that was the most gentle way to treat this. I took another pH reading and it was down to 8. I checked GH and KH to see what they were doing. Sunday the KH had barely been reading - probably under 17.9 ppm. It is now reading right between drops on the API drop test, 89.5 to 107.4. The GH on Sunday had read 143.2. It is only slightly higher now - it only took one more drop with the API drop test which won’t give me precise readings between drops. So more than the 143.2 on Sunday, but no more than 161.1. So, I don’t think I’m stressing the Betta with big changes in GH. The only problem is that really big pH jump when I added the fresh water with baking soda. I don’t want to keep making changes which may do no good and just stress the fish. I’m figuring at this point I just monitor the pH closely and continue to make frequent water changes to lower it slowly. Any other ideas? (I don’t think you need this data, but my ammonia readings are consistently 0, nitrite 0, and nitrate about 10 ppm.)
<See above. The aim was/is to make a bucket of slightly hardened water, do the water change with that, and gradually, over the weekly water changes, raise the carbonate hardness. Again, to stress: my goal is/was to add a little sodium bicarbonate to the bucket of water, test that it make sure it's sensible for your fish, and then add that to the tank. At no time would I recommend adding chemicals sufficient to change ALL the water in the tank at once. That would be stressful. Let me repeat a third time: add a tiny (1/10th tsp) quantity of sodium bicarbonate to 1 gallon water; test the KH and pH; if these are sensible, then use this water; if not sensible, remove some water, add some fresh tap water, and test again. Don't add anything to the tank you think is "too hard" or "too alkaline". Make sense? Cheers, Neale.>
Re: No rush question - pH slowly rising in Betta tank - EEK, big rise after sodium bicarbonate treatment     12/24/16

I understand and will follow your instructions, except the bit about using 1/10 teaspoon sodium bicarbonate per gallon in the water I use for changes so that the entire aquarium is at that proportion eventually. The aquarium water WAS 1/10 teaspoon sodium bicarbonate per gallon - total tank - when I added the 1 gallon yesterday with enough dissolved (1/2 teaspoon) to bring entire aquarium to 1/10 teaspoon per gallon.
<This is where you going wrong. This is a 5-gallon tank, right? And let's assume we're sticking with 0.1 tsp per US gallon. So total would be 5 x 0.1 = 0.5 = half a teaspoon. But DO NOT add this much!!! Let's assume your tank starts off with no sodium carbonate. You take 1 gallon out. You draw 1 gallon of tap water into a bucket. You add 1/10 tsp sodium bicarbonate to this. Dissolve. Add to aquarium. Wait a week. Do another water change. Remove 1 gal; draw 1 gal new tap water; add 1/10th tsp sodium bicarbonate. Repeat for the rest of time. Make sense? Never, EVER add enough buffer salts for the whole aquarium during one water change. The aim is to make slow, incremental changes.>
I checked KH in the aquarium when it went way up, and in a gallon of water to which I added 1/10 teaspoon sodium bicarbonate - same KH - and both with pH over 8. It is obviously too much - made pH way too high.
<Can be; hence the need to experiment. Try filling a bucket with 2 gallons water, add 1/10th tsp (i.e., 1/20th per US gallon total). Dissolve. Measure hardness and pH. See what you get. If it's better, make a note of how much you used, and use that amount instead. Because sodium bicarbonate is so cheap, this approach isn't really going to waste that much money. Pennies a year.>
So I don’t think that water with that much sodium bicarbonate will work for the water changes if I expect to have any impact on the pH or the concentrate of sodium bicarbonate. I think I need less sodium bicarbonate, even though I know that lowers KH and makes pH less stable. But 1/10 teaspoon is clearly just too much in this water unless I want to maintain this pH of more than 8.
<See above.>
I’m now adding water with NO sodium bicarbonate to bring down the pH - and to dilute the amount of sodium bicarbonate in the aquarium (mixing it first with some water removed from tank to keep the pH difference of the water I add from being too big and stressing my Betta again - it doesn’t take too much of the tank water because of the high KH, high sodium bicarbonate concentration, in the aquarium).
<Do small water changes each day and your fish won't be stressed.>
When I get this down to a lower pH, I will start using water which has a small amount of sodium bicarbonate to maintain KH as best I can. My RO water starts out under 6.0.
<Which is very low. My concern is actually hardness and pH stability. Bettas are fine at a stable pH 6.0. But an unstable pH that low can quickly cause problems, and besides, very low pH levels affect biological filtration as well, so aren't ideal.>
I can add slight amount of sodium bicarbonate to get it up to about 7.0 - but it will be significantly less than 1/10 teaspoon per gallon I can tell from my experience now.
<Yes; this exactly!>
I will follow your suggestion and change out 10% to 25% per day of the water, no more. I did 10% this morning and will probably do another 10% tonight. The pH is back up to 8.2 after this morning’s water change fully circulated through the aquarium. I don’t think there is any possibility of changing pH more than 0.2 per day - probably it will be less, so it shouldn’t give him a shock again if I keep mixing the new water with the tank water before I add it. Does this sound correct or am I misunderstanding you in some way?
<Seems about right to me.>
Thank you for your help. Elaine
<Most welcome. Neale.>
Re: No rush question - pH slowly rising in Betta tank - EEK, big rise after sodium bicarbonate treatment     12/24/16

It’s clear. I misunderstood you and made a big goof. I have caused a huge pH fluctuation for my fish - probably great deal of stress - and if I had understood correctly this would not have happened. Now, the question is, how to remedy the mistake.
<Do nothing quickly.>
Since he survived the huge pH jump and acts healthy - swimming, active, no gulping at the surface, etc. - I don’t think another huge pH change down would be good. Seems slow correction is better.
<Correct. Even changes to the better should be done slowly. No more than, say, 10-25% volume of the tank per day.>
This morning his tank read 8.3 on pH. I did a 1/2 gallon water change with just RO water treated with Replenish, mixing it with some of the water I removed from the tank so the pH difference would be less.
<Yes, it would be.>
I took a pH reading right after that and it read 8.1.
<As KH drops, pH should drop too; but at the same time pH instability will increase. I would be doing small water changes, each time the new water being made up with 1/10th tsp sodium bicarbonate per 1 gallon. So ultimately the tank water has that ratio of sodium bicarbonate to water.>
I’ll check later to make sure what’s happening. My plan is to continue daily, or twice daily, small changes to gradually reduce the pH by no more than .2 per day. Does that sound like the best course to correct my major mistake? Elaine
<Pretty much. See above. I don't think you can change "0.2 pH per day" because the scale is logarithmic, not linear, and there isn't an easy relationship between pH and dissolved sodium bicarbonate. Cheers, Neale.>

Fwd: No rush question - pH slowly rising in Betta tank - EEK, big rise after sodium bicarbonate treatment - ADD       12/25/16
I know that big pH change last night was NOT a good idea for our Betta. But the darn little guy has created another nice bubble nest today since I did this morning’s water change and seems completely unaware that he should be stressed! No gulping at the surface as our first Betta did if the pH went up. No sign of gill irritation. Still just as active and hungry as ever. Maybe I got lucky. He’s a young (about 4-month-old) plakat, a Thai import. Elaine
<This all sounds very positive. I'd just leave things be this weekend, and carry out normal weekly water changes hereafter, with a tiny amount of sodium bicarbonate added to provide buffering; as discussed previously, enough sodium bicarbonate for that bucket of water, not the whole tank. Cheers, Neale.>

Question on phosphate-buffered chemistry      8/21/16
Hi wonderful people. I have a question on freshwater pH, if I may. If anyone here knows of a good write-up somewhere, a link to it would be wonderful. If not, I'd be grateful for any comments.
<There are a few on the Net; ours:
and the linked files above>
I understand the non-buffered 3-way relationship between alkalinity, ambient/dissolved CO2, and pH. I've seen the charts that let you determine one of them given the other two. I believe I even pretty much understand the underlying chemistry, including the troublesome pH rebound when you add acid, which temporarily increases dissolved CO2
<Mmm; not this, but Hydrogen ion concentration>

and hence overshoots the pH until the CO2 stabilizes with ambient.
<More like "under" shoots, but let's go on>
But my understanding ends when buffering, such as phosphate buffers, enter the picture. I know it must be more complicated, but I'd love to know the basic chemistry and the practical implications (aside from algae!) of using phosphate-buffered chemicals.
<Ahh; very likely (common) is confusion twixt the terms "alkaline" (as in high pH) and "alkalinity" which is a measure of resistance (chemical) to change in pH... basically (pun) there are chemical species that limit up and downward shift in pH by interacting with a given presence of (whatever model you use for determining, designating) acids, bases. Aka "buffers", many in the petfish interest are bound onto phosphate/s (and some folks prefer other sources, like sodium (bicarbonate; baking soda, to avoid adding fertilizer to their system/s)>
By the way, before you say it, I do understand that STABLE pH is at least as important as CORRECT pH, and I assure you that I am not a wild dumper of chemicals.
I keep fish appropriate to my mildly alkaline water (7.2) , and tweak as necessary. This is mostly curiosity. Thank you for any information!
<Mmm; I need to know you (your scientific background) a bit more to likely be more helpful. I taught H.S. chemistry and physics (and bio. classes), and have tried for decades to describe, define these concepts... Soooo, make it known what is unclear, incomplete here. Bob Fenner>
Re: Question on phosphate-buffered chemistry      8/22/16

Bob - Thank you for the response! I really appreciate the work you and others do here.
I'm not a chemist, but I did take (and get A's in) chemistry 101 and 102 in college, so I have a reasonable background.
<?! Better grades than I got!>
I do understand well the distinction between 'alkaline' (high pH) and 'alkalinity' (ability to withstand addition of acid, minimizing pH change until all alkalinity is used up).
<Ah good>
Here's where I'm in the dark. I read somewhere seemingly reliable that the famous three-way relationship between alkalinity, CO2 concentration, and pH can be advantageously subverted by the addition of 'phosphate buffers' whatever they are.
<Mmm; not as far as I'm aware... and the carbonic acid (CO2 in sol'n) bit is throwing me... IF you use carbon dioxide (as a gas) to boost carbon availability... to increase photosynthesis in marine or freshwater systems... this would pertain. Otherwise its (acids) are the same ole proton donors, electron acceptors... Usually we (at least used to) state
their addn. as H+, Hydrogen ions....>
This, of course, can cause algae problems, but it does help keep pH more stable than just using simple buffers like bicarbonate.
<Well; there's a bit more to this. There are a few formats of "Phosphate", and really only the simpler, soluble HPO4 is of issue. Again, in very reductive settings (low pH's like in an anaerobic substrate w/ decomposing organics galore) this is not much of an issue. As prev. stated carbonates, bicarbonates joined with other metals can be easily found>
So I'm wondering what phosphate buffers are and how their chemistry relates to the non-carbonate ionic balance equations that are all over the internet.
<Mmm; let me take a look see for a link: Is this too general?:
<Glad to share, learn. BobF>
Re: Question on phosphate-buffered chemistry      8/23/16

Bob - Thank you for that wonderful link! It did not exactly address my question, but it did provide a lot of fascinating and useful information, far more than any of the other sites I've found. I read it carefully twice and bookmarked it for reading again later.
<Glad you found it useful Tim>
However, that site made a statement that I find conflicts with information I've seen before and experienced myself:
"An important consideration of KH is that you can safely add the buffers (both freshwater and saltwater) that effect KH (Alkalinity) without sudden changes in chemistry, unless your freshwater KH is under 50 ppm (3 dKH) already."
<Mmmm? Don't know what they're referring to here. There are certainly "some" buffers (though maybe not commercial prep.s) that definitely WILL "raise pH dangerously" from here. Again, am guessing, but likely they're referring to products commonly sold for aquarium use>
I've seen many charts and even an online calculator that show the fixed relationship (after stabilization) between CO2, alkalinity, and pH. In particular, for any set CO2, there is a strong monotonic relationship between alkalinity and pH. When I started preparing for a freshwater tank, I set up a bin in the cellar with aeration and constant stirring. I would
add a small amount of SeaChem alkaline buffer, let it stabilize for a day, and then measure alkalinity and pH.
<A good S.O.P.>
Then I add more and repeat. I clearly got this relationship. If I added Acid Buffer later, the pH would temporarily plunge, and then slowly rebound up to the 'stabilized' value.
<Yes; to be expected>
So I don't understand the statement that above 4 KH additional alkalinity does not affect pH. This flies in the face of what I've seen online and experienced myself.
<I understand what you've stated, and agree with your observations. Do you get the gist of my explanation for their stmt. above?>
Anyhow, I've bothered you way too much, and I now have a lot of studying to do from that link you sent. I'll end with one quick question, if I may. I am keeping a 65-gallon peaceful mixed community tank. Rather than chasing pH, I just keep the alkalinity at a stable 4 KH (with small amounts of SeaChem acid and alkaline buffer at water changes) and the hardness at 8 GH (with SeaChem Equilibrium). I keep an eye on the pH but it appears to be stable, so I don't mess with it. Is this reasonable?
<Yes it is>
<Thank you for sharing. Cheers, Bob>

Water conditioner claims to boost Alkalinity. (RMF?)  5/6/09
First I would like to say, You guys and gals provide a service that is beyond any estimated value, and I literally spend hours reading from this information. I forbid any of you, from passing from this earth before me!
<Thanks for this kind (if rather bizarre) compliment!>
Though I have searched through the many posts and replies, I have yet to find an answer to my concern. Forgive me if it is otherwise.
<Fire away.>
My question is.. In your view, and without mentioning a specific brand ,If one had an aquarium ,and the water therein was moderately hard, would the use of a dechlorinator that claims to boost alkalinity in your view,, be detrimental to the fish (i.e.) Discus, and rams.
<It would likely have trivial impact either way. Unless the bottle contained a really concentrated carbonate or bicarbonate solution -- which it wouldn't -- it would be so diluted as to be of negligible value. Take a look at how much cichlid salt mix you need to make hard water for Malawi cichlids: a tablespoon of Epsom salt, and a teaspoon each of marine salt mix and baking soda, per 5 gallons of water. So a few drops of water conditioner...? Gimme a break... It's more marketing than anything else, I'd warrant. Possibly it contains some carbonate in the recipe, and the Marketing Department decided to flaunt this as some kind of virtue or special feature. Of course, you can always test the stuff and see: measure KH before and after adding it, and see what happens. Discus are fairly unfussy about carbonate hardness, at least in the case of tank-bred Discus; Rams are a bit more delicate, as you probably know, and I'm glad you're keeping them with Discus in a system optimised to these fussy Dwarf Cichlids. But as a one-off purchase, I doubt using a small bottle for a couple of months would put even Rams at risk.>
The normal water conditioner I use does not make such a claim but the chain stores, and fish stores around my neck of the woods do not carry it and I must order online. The product I am questioning which is readily available, addresses ammonia, chlorine ,and chloramines as well as heavy metals. Claims not to affect the ph, and boosts Alkalinity.
<I'd go for this if I had the option, but honestly, I doubt it would make much difference.>
As I am barely able to keep the Discus and rams with the tapwater I have, I am doubting the wisdom of switching to this particular product.
<Fair point; and in this case, tank-bred Discus and farmed Bolivian Rams (M. altispinosus) would likely be the best bet, since both thrive in moderately hard water.>
Thanks in advance for your thoughts.
<Cheers, Neale.>
<<Mmm, not alkalinity, but apparent pH may be shifted, albeit temporarily by such chemical dechloraminators... Don't know how much I/we want to belabor or discuss re this possibility... but I do completely agree with Neale's assessment... Chemically changing ammonia presence to un-ionized will appear to change alkalinity perhaps... but in reality, this is only a temporary appearance. BobF>>

Low pH 11/8/07 Hi, I am having a problem raising my pH. It stays at a 6.0. The alkalinity is at 40 and the hardness is at 300. I tried the pH increase but it didn't help and am trying the proper pH 7.0, but read that it is bad for plants. I have several bamboo, a short round leaf plant that I don't know what it is and an onion bulb shaped plant. The tank has an assortment of community fish. What can I do to fix my pH and will the treatment kill the plants? Thanks so much! Julie <Julie, adding chemicals like "pH Up" to raise pH is generally pointless. Those chemicals are really buffers. That is, they are designed to stabilise the pH at a certain point once you've already brought it up (or down) to that pH level. So if you have a Lake Malawi aquarium with lots of nice hard water, adding a "pH Up" product will make sure the pH stays at the 8.0 value Malawi cichlids like so well. But if your aquarium is way off base, these buffering potions will be overwhelmed. In this case, you need to sit back and look at what's going on. You aquarium has a low carbonate hardness. This means that the pH easily falls towards the acid end of the pH scale. The way to remedy this is to add carbonate hardness. There are multiple ways to do this, but the simplest is to make a mixture of equal parts bicarbonate of soda, Epsom salt and marine salt mix. Add a teaspoon to each bucket of water, and stir well. Test the carbonate hardness and pH of the water. It should be much higher. If it's too high, repeat using less of the mixture; if it's too low, repeat using more. What you want is something around 100-200 mg calcium carbonate (6-12 degrees dH, 5-10 degrees KH). This water should have a pH around 7. It will be perfect for a wide range of community tropicals, with the exception perhaps of livebearers, which like water that is more hard and has a higher pH. Tetras, barbs, Gouramis etc will all thrive under such conditions, and the biological filter and plants will also do their best. One thing: make these remedial actions slowly, changing no more than 25% of the water per day. While aiming for neutral pH, moderate hard water is ideal for the community tank, rapid changes in water chemistry can be lethal to fish. As for your plants, the "onion" is probably Crinum sp., perhaps Crinum thaianum, a lovely aquarium plant. Bamboo doesn't normally survive in aquaria, especially when kept submerged. It might survive allowed to grow out above the tank, but that's not really practical. Do be aware that many aquarium shops sell non-aquatic plants to unsuspecting fishkeepers. It's a sad state of affairs really. You need to know what plants you want, and THEN go shopping, and not go shopping and come back with a bunch of mystery plants. Good luck, Neale>

Help!! Ph Crash??    01/13/2008 Hello WWM crew, <Hello,> This might be repetitive, but as always, got to congratulate and admire the services you people do. If this question once again gets to Neale, I would like to thank him very much for all the past help he has given me. Anyhow, I have a very weird situation on my hands and hope that you could help. <Weird away...> I currently have a 170 and 55 gallon freshwater tank that I do a 50% water change weekly with aged tap water (both tanks has been up for approximately one year). As of last week, my PH value is at 7.6 for both my tanks (common stable). As of today, I checked my water parameters and found that the PH for my 170 gallon tank is at 6.4!!! <OK, that's a big swing and definitely not good. Not fatal, but not good. Does suggest a lack of carbonate hardness, which is at least relatively easy to rectify.> I have two test kit that I verify with (API liquid test kit and Mardel quick dips). This have never happened to me before. The only thing that I have done differently since the last water change was change my brand of dechlorinator, from Prime to Amquel+ and NovAqua+ due to the great reviews that they have gotten. <If one dechlorinator removes ammonia from the tap water but the other doesn't, then the ammonia can result in a higher-than-expected pH reading. But a quick check suggests that both Amquel and Prime remove ammonia. Not sure NovAqua does.> The tank does have a large piece of driftwood that has been in it for about one year now. <Bogwood will lower the pH by producing acids that neutralise carbonate hardness. That said, a moderate amount of aged bogwood shouldn't have a huge effect except in very soft water aquaria.> I can't figure out what could be shifting the Ph so much. Could the new dechlorinator be affecting my readings? <Can't see why.> This also seems invalid due to the 55 gallon tank reading normal as always. The 170 is currently equipped with three 405 Fluval canisters, and a Vortech MP40 powerhead, which apparently by itself pushes 3000gph. I think I do have ample circulation. Total hardness for the tank reads approximately 120ppm and total alkalinity at 0ppm. <Ah, here's at least one issue. Alkalinity is essential to any aquarium. Total hardness itself is of secondary importance, and is mostly about how fish osmoregulate. Carbonate hardness (measured in degrees KH) is far more important, as it tells you how well an aquarium prevents pH changes. As things stand now, if you have zero alkalinity, which would suggest zero carbonate hardness as well, your aquarium has next to no ability to resist pH changes. This is because the other minerals in the water (the ones making total hardness) don't combine with acids. All they do is float about in the water.> Very awkward. Tank is currently stocked with one L25 Scarlet Pleco at 10" and one 6" Flowerhorn cichlid. Ammonia at 0, Nitrite at 0, and Nitrate at 30ppm. I have not seen any adverse affect on the fishes as of yet. I plan on setting another batch of tap water overnight tomorrow with dechlorinator and perform a change on Sunday. Its early Saturday morning right now. Any ideas? <Raising the carbonate hardness is essential for Flowerhorn cichlids, given their Central American ancestry. I'd suggest making up a batch of Malawi Salts, and adding these at a 25% to 100% dosage until you get the right set of pH and carbonate hardness (i.e., KH, not total hardness) values for your needs. You can buy these salts from stores, or you can make your own. Here's one handy-dandy recipe for Rift Valley salt mix: Per 5 gallons/20 litres * 1 teaspoon baking soda (sodium bicarbonate) * 1 tablespoon Epsom salt (magnesium sulfate) * 1 teaspoon marine salt mix (sodium chloride + trace elements) Mix well, dissolve into the bucket of water, and then add to the aquarium. Don't do huge changes at once, but do water changes of 25% per day until the tank is where you want it in terms of pH and carbonate hardness. I'd recommend at least 7 degrees KH, and ideally 10+ degrees KH, for most Central American cichlids. You should find this prevents pH changes completely.> Also, is it possible for water quality to remain cloudy due to insufficient surface area for the bio load to attach to and stabilize and remain free-floating? I really doubt that I am overfeeding since I feed usually once a day and make sure all food is consumed. Right after a major water change, water would be crystal clear for a day or two and would get cloudy again. It has been like this ever since I started. No problem of this on my 55er. <Curious. But no two tanks are the same.> Lastly, any opinions on Prime vs. Amquel+/NovAqua+? <None. Never used either.> My only concern is the concentration levels. Prime seems to be so much more concentrated, at 5 mL per 50 gallons of water. While, Kordon's product suggested dosage level is at 5 mL per 10 gallons. Any thoughts on either product? <Nope. All dechlorinators do the job, so I tend to buy whatever is on sale! This sort of thing may matter more for fancy-pants marines, but freshwater fish generally don't care so long as the chlorine is removed.> Ok, that's all for now. All help is greatly appreciated. Thank you so much and be safe. Andy <Or as we say in England: "Be good, or if you can't be good, be careful." cheers, Neale.>

Re: pH problems -- 10/10/08
Thanks Neale that was very helpful. Now let me just bother you with one more question. Do you think I can just place the crushed coral in a fine mesh bag and just lay it on top of my substrate and putting an airstone next to
it instead of using a box filter?
<Nope, won't work. Filtration -- whether chemical, biological or mechanical -- relies on moving water being moved past the media. This is why floating a sponge in a tank doesn't turn it into filter -- the water has to be pumped through the sponge. Moreover, once the chemical media gets covered with algae, bacteria and silt, it becomes isolated from the water, and so stops working. You need to be able to clean the media every few weeks under a hot tap to wash away this stuff. Putting the crushed coral in a filter -- whatever type of filter -- is the only way this system works reliably. Notions based on adding coral sand in the gravel or putting Tufa rock in the tank won't work for the same reasons. Without a flow of water and regular cleaning, any chemical buffering offered initially will fade away in a few weeks.>
Or do you think this could just trap a lot of waste and become a hazard to the aquarium?
Your help is much appreciated.
<Cheers, Neale.>

Coral Chips use in FW for Alk.   8/23/07 Hi Crew / Mich, <Alan, Bob with you this time> Will coral chips helps to buffer up in my fresh water aquarium? I heard a lot of hobbyists are doing that to maintain the neutral Ph, does it help or is it a myth? Thks. in advance. Cheers. Alan <These sources of calcium carbonate do/will indeed provide alkalinity, reserve. Bob Fenner>

Re: Coral Chips use in FW for Alk.   8/24/07 Dear Crew, <Alan> Thks. for the prompt reply. Further to my questions on coral chips, what is the amount to be used in terms of weight? <Best to experiment here... try a few ounces... in a net-like bag (perhaps a Dacron one sold for this purpose in the pet-fish interest), rinsed (to remove dust) and placed in your circulation/filter flow path... test the water every few days... for pH, alkalinity> Will over usage of coral chips caused Ph readings to go beyond 8? <Mmm, doubtful... not "that" soluble in most freshwaters...> Thks. in advance. Alan <Welcome. BobF>

Re: Coral Chips  8/27/08 Dear Crew, Hope I'm not a nuisance to you guys. I have one last questions. If my pH reads 6, am I right to say that the coral chips are more soluble? <They will be more soluble in lower pH water, yes. BobF> Thks. in advance. Alan

Crushed coral to pH buffer a FW system Hello guys, <Jon-Jon> Here is my set-up: 8 inch Arowana, 125 gallon fish tank, 2 emperor 400, 1 Eheim canister 2028, and two 250 watt titanium heater set at 82 degrees Fahrenheit. I do water change (25%) twice a week, and uses Amquel plus and Novaqua. I am concerned about my PH since it is low :( here are my test results: water in tank's PH = 5 tap water = 7 GH and KH for both tank water and tap water = 3...and states that I have soft water <Yes... would very likely benefit from the addition of something in the way of a buffer> with these tests, it tells me that I have soft water (tap) ....and it decreases once it is mixed with my tank water (PH becomes 5). I just bought 15 pounds of crushed corals.  I used 2 nylon bags and each bag is around 3 pounds.  So the total in my tank right now is approximately 6 lbs. My plan is to just continue to do 20% water change twice a week....and hoping that w/ my 6lbs of crushed corals and my tap water (7 PH)...will eventually bring up the PH of my tank water...w/o having any drastic change in ph. questions: 1.) 6 lbs of crushed coral is enough?   <You'll soon find out... this amount should have a measurable effect> 2.) how many lbs of crushed corals do I need to slowly increase the PH of my tank...w/ twice a week water change (20%)? <Not able to state very accurately w/o knowing the solubility of your given coral substrate (varies) or its placement near circulation... but I suspect that this change will bring the pH somewhere closer to six for a few months... then when the more easily soluble parts of the coral are gone, slip back to the fives> 3.) how will I avoid big fluctuations of PH while I am trying to increase it? <The best route is to pre-mix your change water (in a designated bucket, trashcan) and add buffering material... like the crushed coral or if it were my choice, sodium bicarbonate (baking soda) with a recirculating pump/powerhead and a heater... for a week or so... and test for its pH and possibly alkalinity before using> 4.) how will I avoid crushed corals to spike the PH? <It won't... it isn't "that soluble" or that "strong" or rapid an alkalizing substance> 5.) Once I reach my desired PH (6.5-7).....how will I be able to maintain it?  Can I remove the crushed corals?  As much as possible, I want to have a bare bottom tank. <Mmm, you will find a "happy medium" in the amount of alkaline buffer/capacity you're adding, manipulating. You will need to leave the coral in place, periodically replenish it to maintain an elevated pH> 6.) do you have any recommendations on how I can safely maintain the desired PH w/o having any crushed corals? <Yes... as mentioned above, by pre-treating, storing your new water> 7.) any recommendations on how I can safely increase my PH w/o a drastic change? <The above will do it... by adding enough (you will need to experiment, but a few teaspoons per ten gallons is about right) baking soda to the new water, changing this out during maintenance, you will find the pH stays a bit higher with each change... Not dangerous. Bob Fenner> thanks so much!!!!

Using peat to lower the pH I have a 25 gal aquarium. I use a canister filter filled only with biomedia (material that provides bacteria with a large colonizing surface) and the regular mechanical filter pads. My local tap water has the following water parameters: pH around 8 (+- 0.2) and KH=7. The fish I want to keep (central and south American cichlids) require neutral water (pH range: 6,8-7.3 appr.). The aquarium is decorated with driftwood, but it doesn't have a measurable effect on the water chemistry (pH and KH are the same with tap water). Zeolite (which I used in the past) did lower the pH and soften the water. With Zeolite I got a pH of 7.3 and KH around 3-4 (Germ. deg.). Zeolite is a cation exchange material which can bind ammonium and other cationic compounds (possibly calcium and magnesium and thus the low KH value). <Yes> However, this not only deprive Nitrosomonas colonies of their food source (disrupting the nitrogen cycle), but it releases species of cations in the water (possibly sodium) which in high concentrations can be fatal for the fish. <This is a little discussed possibility> Now instead of using Zeolite, I am thinking of using peat. Peat binds calcium and magnesium cations and exchanges them for hydrogen cations. So it lowers both water hardness and the pH of the aquarium's water. Moreover blackwater will bring out striking fish coloration! <Yes to all> I have seen many commercial brands that sell aquarium-safe peat. This is probably intended to be used in a canister filter. <Mmm, or a box filter... or in a Dacron bag placed in an area of water flow...> However, I am not sure about what amounts of peat to use in order to bring the water to the desired pH values. I think that using a plastic barrel (with dechlorinated and properly heated water) pre-treating it with a nylon bag filled with peat is safer, as the effects can be controlled before the water change is made. What methods do you have in mind, concerning the use of peat for lowering the pH? <What you describe is fine... the amount cannot be accurately guessed as peats are not consistent in their quality in this application... best to soak, even boil them in a bit of water, let cool, strain (and pour the boiled water in with your mixing water) and use> Does a KH reading of 7 germ. deg. indicate a sufficient buffering capacity or should I experience sudden pH shifts? Thank you in advance. Spyros <Good questions. A dGH of 7 should be fine for buffering. Bob Fenner>

Freshwater, alkaline well, Acid Buffer use? First off, let me say thank you for such an informative website.  It has been extremely useful and fun as I read it nearly daily. <Glad to find it useful, of interest to you> I'm writing with a question regarding the use of SeaChem "Acid Buffer", specifically I would like to know whether it can be used alone to reduce the KH and pH of our naturally hard, alkaline well water for use in our freshwater tanks, or if the ingredients in Acid Buffer are designed to interact only with those in SeaChem's "Alkaline Buffer" and would therefore be inappropriate if used alone. <Can be used by itself... but am wanting to offer a bit more input here... Especially if you're going to be using a bunch of water... far better to investigate R.O., Deionization technology... for your drinking, cooking use as well as pet-fishing...> We do own/use a Coralife RO/DI filter, and would like to mix RO/DI water with well water in order to produce water change water with a GH and pH appropriate to the fish in our three tanks. <Oh! Good idea... sheesh, I ought to (wake up, and) read ahead...> Let me preface my questions by saying that our fish currently appear to be healthy, but after moving from Connecticut to Vermont in Aug 2004 our tank went from a steady pH around 7.0, up to a steady pH around 8.0-8.1, apparently as a result of our use of the well water here. <Yes> The root of my discomfort comes from the fact that I still don't have what I feel like is a going-forward water-change plan as to the contents of my make-up water - do I use 80% RO/DI and blend in 20% tap, getting soft water with little alkalinity buffering, yet still a high pH, or do I need to move to simply using pure torn-down RO/DI water and doing an add-back of everything that has been lost?   <I would go with the first approach... try the one-fifth source water and measure what this looks like pH, alkalinity wise> I've been trying to find SeaChem "Equilibrium" and "Alkaline Buffer" at LFS with no luck, even to the point of their ordering it for me and not having any arrive. I would like to know how I can best go about creating water for water changes, given the difficult well water that we have.  Is it possible for me to simply buffer the well water down to a given pH using "Acid Buffer" alone? <You could (I would not)... as this may well take quite a bit of doing... lots of buffer, time to mix, stabilize, test...> If so my plan would be to mix this water with RO/DI water at a ratio giving my desired GH values (more than the 3 dGH resulting if I just mix well water with RO/DI until a reasonable sub-8.1 pH results, but not quite the 14 dGH that is in the well water right out).  I'm also a little concerned about the phosphate levels in the tanks (~ 1mg/L) impacting the buffering provided by Acid Buffer and/or Alkaline Buffer if I ever manage to find any of that product. <Mmm, I strongly advocate the use of storage containers, dedicated to holding your water... ahead of use. Perhaps something in the way of an "intermediate" tank/container with live plants that will "take out" a good deal of the biomineral, alkaline content here... e.g. Ceratophyllum... We should chat up the types of livestock you keep, want to keep... if you're intending to breed fishes that require soft/er, more acidic water... but starting with "cleaner" RO and adding back some source/well water is likely the route to go here... or to switch to Great Lakes African Cichlids! This is what I have and they relish large water changes with our "liquid rock" S. Cal. tap> My apologies for the length of this message, and thanks for any assistance you may be able to provide. Test kits: Aquarium Pharmaceuticals (KH, GH, NO3, NO2, NH3/NH4) (After seeing how inaccurate the AP pH tests are in comparison to the pH meter, not sure I trust these) Milwaukee SMS 120 pH meter (calibrated to 7.001 and 10.000 buffers) Salifert PO4 Well water parameters: Fresh from the tap KH 12dKH, GH 14dGH, pH 7.0, PO4=0, NH3/NH4=0, NO2=0, NO3=0 120min of aeration KH 11-12dKH, GH 14dGH, pH 8.4, PO4=0, NH3/NH4=0, NO2=0, NO3=0 Tank parameters: 10g - Swordtails (1 full-sized, many fry), 1 Otocinclus affinis, 76 deg F pH=7.8, KH=3dKH, GH=6dKH, NH3/NH4=0, NO2=0, NO3=20ppm, PO4=1mg/L planted: 1 Lg Amazon Sword, 1 Java Fern, 1 Crinum, much Bacopa up since: 1 Jan 2005 Products used: Aquarium Pharmaceuticals Stress-Coat Aquarium Pharmaceuticals Aq. Salt (1tsp/3gal w/H2O changes) Nutrafin "Plant-Gro - Iron Enriched", very occasionally (N=0.15%, B=0.0005%, Cu=0.0005%, Fe=0.26%, Mn=0.05%, Mo=0.0007%, Zn=0.003%) Tetra Whisper 10 filter (Bio-bags + activated carbon) 60W incandescent lighting gravel (believed inert, not yet tested) Food: TetraMin large tropical flakes TetraColor color-enhancing flake Tubifex worms (occasionally) 29gA - 1 Blood parrot Cichlid hybrid, 6 Corydoras spp., 80 deg F pH=8.1, KH=4-5dKH, GH=3dGH, NH3/NH4=0, NO2=0, NO3=25ppm, PO4=1.5mg/L no plants no CO2 infusion, occasional Aqua up since: 15 Aug 2004 (after a move), several years beforehand Products used: Aquarium Pharmaceuticals Stress-Coat Aquarium Pharmaceuticals Aq. Salt (1tsp/3gal w/H2O changes) Aquarium Pharmaceuticals Nitra*Zorb, occasionally TetraAqua "Easy Balance" (1tsp/5gal w/H2O changes), for the last three H2O changes without apparent effect -- claims to stabilize pH and alkalinity Tetra Whisper 40 filter (Bio-bags + activated carbon) Penguin 330 filter gravel (believed inert, not yet tested) Food: TetraMin large tropical flakes bloodworms (San Francisco Bay Brand) Penn-Plax Pro Balance "Red Parrot Fish Food Diet" 29gB - 1 Honey Gourami, 4 med. swordtails, 4 Corydoras panda, 78 deg F pH=7.8, KH=3-4dKH, GH=4dGH, NH3/NH4=0, NO2=0, NO3=10ppm planted: 2 Amazon Sword, some Bacopa, 1 sm Barclaya no CO2 infusion up since: 21 May 2005 Products used: Aquarium Pharmaceuticals Stress-Coat Aquarium Pharmaceuticals Aq. Salt (1tsp/3gal with H2O changes) Nutrafin "Plant-Gro - Iron Enriched", very occasionally (N=0.15%, B=0.0005%, Cu=0.0005%, Fe=0.26%, Mn=0.05%, Mo=0.0007%, Zn=0.003%) - less than in 10g Tetra Whisper 40i filter gravel (believed inert, not yet tested) Food: TetraColor color enhancing flakes Tubifex worms (occasionally) Thanks! -Brian Pardy <And you. Bob Fenner>

Homemade Chemicals for adjusting FW pH Hello, <Howdy> Read some of your articles on Wet Web Media '¦they're pretty informative.  I wanted to reduce the PH in my 50 gallon tank and ran out of discus buffer. Though about adding a few drops of vinegar (on suggestion of a colleague at work)  to the tank on a daily basis.  Would this work or is this harmful to the fish? Thanks, Sam Rahal. <Can work, though in the long/er term would look into other organic acids, means rather than acetic... tannins and flavins are better here... starting with water with less mineral to begin with a plus. Bob Fenner>

pH and Buffering... "White Diamond" = Zeolite  I don't think the ammonia is like I thought I got another tester and it shows no ammonia levels. Was using a test strip and had trouble reading it. What other method would be good for testing ammonia levels. <<Any reliable test kit will do; but make sure you are testing both NH3 and NH4, your White Diamond will change the ammonia that the fish produce into ammonium, so perhaps your current test kit isn't actually testing properly. Check your test kit to make sure you are testing for both!>> I have had this tank going for 10 years. Had an Oscar in it for 8 years until he died 4 months ago. In the 10 years I never checked any of the levels of anything in my tank. Until I was reading on this site about checking nitrite, nitrate, and ammonia levels. For those 10 years I have always used white diamond and black diamond. <<I understand. However, it really doesn't make sense to run White Diamond, while it won't harm anything in an established tank, it is just a waste of money. You do not need it, it serves no purpose whatsoever in a healthy, established tank.>> My weekly cleaning schedule goes as follows, 50% water change. First emperor change foam filter, second emperor rinse foam filter, and once a month clean and change all filters in emperor's but only on alternating weeks. I never clean or change the bio wheel. <<Okay, good.>> I had read on this site that Oscars like a 8.0 ph and I was thinking  about using proper ph 8.2 what do you think. The directions say I need to use African cichlid salts with it for it to work. <<I doubt any Oscar feels at home at a pH of 8.0. While they will tolerate it, why waste more money raising your pH unnecessarily? A bit of research will show you that Oscars come from the Amazon river, and the pH there is definitely not 8.2. They are more at home in a pH ranging from 6.0 to 7.5. I would assume a neutral pH to be best, around 7.0 should be fine. As long as it is stable, and you are not constantly messing around trying to change it. If your tap pH is neutral, then leave it as is.>> <<-Gwen>>

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