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FAQs on pH, Alkalinity, Acidity: Adjustment

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 Products, 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

First: Determine if you really need, want to adjust your pH... Not always profitable to do so. For too low Alkalinity, the addition of carbonate, bicarbonate containing materials... Rock, substrate and such. Perhaps removing reductive (acidic) influences. For too-high Alkalinity, time going by, the use of some inorganic acids, peat...

Daily ph fluctuation. 1/17/15      1/6/18
Hello Bob,
<Hey Bill>
Continuing our conversation re: Daily ph fluctuation. 1/17/2015.... About 6 months ago (June 2017), i put in the tank a few shards of "Pennsylvania Blue Stone", total about 1 square foot. Over the months, the ph slowly rose and i correspondingly backed off on the baking soda (for the last month or so, no baking soda at all was added in the daily water changes).
Ph is now "rock" solid at 7.8, which is bit higher than I want (a few fish are flashing too much, regularly; and i do have some soft water species in there, e.g., Farlowella sp.). Question: Over a period of months, can i "adjust" the ph down by removing some of the bluestone?
<Likely so; yes>
Say i leave in 4 sq in, will the ph drop, but not 'all the way'?
Or is it that that smaller piece will just dissolve at a faster rate and maintain the 7.8 ph?
<A matter of surface area, current, solubility of the area exposed... but less material, area, current (and a few other factors; time, temperature...), less effect>
<Welcome. Bob Fenner>

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>

Re: Comet with Fish Lice, Anchor Worms, or Tetrahymena? Now:  FW, ph, Alk.   3/27/16
I just measured my Nitrite and pH levels with my Tetratest Laborett. This kit is 4-5 years old so should it still be effective? I did not see any expiration date.
<Should be okay, but yes, the chemicals do "wear out" with time. They break down with exposure to light, oxidise, whatever...>
My values:
*Nitrite level <0.3 mg/l (yellow color),
pH 5.0 (light yellow color)*
<Sheesh! That's your problem right there.
Do not, Do Not, DO NOT try and change the pH in one fell swoop. Instead, go read this:
Scroll down to the Rift Valley salt mix bit. Make up a bucket of water using this recipe, you can skip the marine salt mix if you want, or substitute non-iodised cooking salt if you have some. Regardless, the carbonate hardness from the baking soda will raise carbonate hardness and in turn pH. General hardness comes from the Epsom salt. Do a series of water changes using buckets of water of this sort, but don't change more than, say, 25% per 24 hours. Rapid pH changes are dangerous to fish, even if you're changing them to the better. In the future, once you find the pH levels off around 7.5, you can try half-dosing the Rift Valley salt mix, but Goldfish in particular thoroughly enjoy "liquid rock" hard water, and'll be just fine with the full whack. Does this all seem doable?>
So it looks like I desperately need to increase my pH to around 7-7.5. How can I do this? The test kit instructions for pH said that I need to do a 1/3 water change if the value lies below 6 or above 8.5. There is a
possibility that like you said the pH has become acidic due to the rusting brass/copper and that it is dangerous if below a pH of 7.
<Hope this helps, Neale.>
Re: Comet with Fish Lice, Anchor Worms, or Tetrahymena? Not this: Adjusting pH          4/5/16
Hi Neale,
My 55 gallon tank that I talked about previously still has a pH of 5.0 after doing a 33% water change about a week ago. I have on hand crushed oyster shells (which I normally use to supplement calcium for my Ramshorn
and Malaysian Trumpet Snails in a few of my other tanks) that I read online can help increase the pH a little but that it is better to instead use something like Seachem's Alkaline Buffer ($6.30 on Amazon.com). How do
these two methods compare to the Rift Valley Mix and if I use them instead, how should the dosing increments be, e.g. every 24 hrs, every 48 hrs, etc.?
<The short answer, Jason, is that they don't compare. Adding shells (or any other calcareous media) to an aquarium works has a slow effect on pH and hardness. Adding soluble minerals (like Rift Valley mix) brings immediate
changes to the bucket of water, and by extension, to the aquarium it's added to. Let's look at the details. If you use a calcareous substrate, the big advantage is that it's easy to do. Add some crushed seashells or coral sand, then hope for the best. Over the next few days measure the pH (and ideally the carbonate hardness as well) and you should see them both go up. They normally level off around pH 8, and "very hard" on the carbonate hardness scale, but this will depend on your starting point and how much of such media you used. Obviously the big downside here is that this is al very hand-wavy in terms of predicting what's going to happen. If you're keeping genuinely hard water fish (livebearers, brackish, Rift Valley cichlids) then using just calcareous media is fine, and the uppermost limit the water chemistry will change to will be just fine. But if you're keeping a mixed community it's easy to overdo the amount of calcareous media used and end up with water that's too hard and alkaline for them. Another problem is that over months/years the buffering capacity of calcareous media diminishes as the particles get covered with detritus and algae. This is the source of those pH crashes you hear about in old tanks. So if you use the calcareous media approach, regular maintenance and partial replacement will be required. What about adding Rift Valley salt mix? You make it up in the bucket, do the tests, and you know what you've got. There is little scope for change between water changes. So week-in, week-out you should be maintaining nice steady conditions. The downside is that the
minerals in the water provide some, but limited, buffering capacity against acidification. If you skip several weeks' worth of water changes, that buffering capacity can become exhausted and the pH will start to go down.
That's different to the calcareous media situation where the more acidic the water, the faster the seashells dissolve, returning the pH back to 7.5 or 8 or whatever. Obviously the ideal is to combine both: buffer each bucket of water, but incorporate some crushed coral or shells in the substrate (or in an easily cleaned/replaced media bag inside a canister filter) to buffer against dramatic changes. Make sense? Cheers, Neale.>
Re: Alk; pH        4/6/16

What about solutions (or maybe its a solid?) you add to the water like Seachem's Alkaline Buffer ($6.30 on Amazon.com)? What do you think of using something like this?
<These are simply prepackaged versions of the Rift Valley Salt Mix. If you visit their webpage, there's this in the FAQs:
"Q: Is your Alkaline Buffer a sodium bicarbonate?
A: Yes, it is a sodium bicarbonate based buffer"
So there you go. Much, much cheaper to "roll your own" using the Rift Valley mix, adjusting the ratios of the three components until you get the precise pH, GH and KH readings you want (change the sodium bicarbonate for
pH and KH, the Epsom salt for GH). But some folks put a premium on convenience, and that's what the Seachem Alkaline Buffer is all about.
Cheers, Neale.>
Re Softening FW       4/7/16

On the contrary, what would you use to soften water? I've got a few tanks with 8.0 and 9.0 pH's, so I think it would be a good idea to bring down their pH's to around 7 to 7.5.
<Read here: http://www.wetwebmedia.com/fwsubwebindex/fwsoftness.htm
and the linked files above. Bob Fenner>

pH Control in Multi-tank System    10/9/14
Hi Crew,
I have a unique tank scenario which is somewhat predictably creating some unique problems. I have a store with about a 2000 gallon system and 55 variously sized tanks. Most are planted with lighting and substrates
appropriate to the species stocked in each tank. The tanks all drain through filter socks into a 275 gallon sump, then through a couple 55 gallon barrels filled with Seachem Matrix, and consequently into another 275 gallon sump which holds our heaters and settles the water a bit before being pumped through TMC UV sterilizers back into all the tanks at about 6000-8000gph (back pressured by 55 ball valves at different adjustments so
it's hard to calculate).
<No other... mechanical/cartridge filtration? I'd likely add this>
The way the system is set up, water changes can only be done in about 50 gallon increments at a time so I have them on a schedule to change twice daily for a total of 100 gallons per day. I was still accumulating
nitrates and phosphates so I've recently upped that to 200 gallons a day and have yet to test the success of that change, but my question is on a different matter.
<Actually related... i.e.; by increasing your alkalinity you will very likely reduce (as in the chemical term) a good deal of your NO3 and HPO4>
Our water from the tap gets filtered via carbon and comes into the system with a high pH of around 8.0. This was resulting in some nasty strains of algae and I think stress on some fish that have been struggling in this new system (Cardinal Tetras, Blue Rams, some others). So I put added a new source supply of RO water which the system uses to perform top-off and water change when the pH is above 7.2. At first glance, I thought the new system was working great. Within a couple weeks my pH had dropped to stable 7.2 and I'd say the system was using about 50/50 RO and tap to maintain that balance. However, I'm looking for better plant growth so that I can supply customers with plant cuttings from some more difficult species in their submerged form. So I thought about adding co2 (we are currently regularly using Flourish Excel but its not really cutting the mustard).
<Again; likely at least partly related to a dearth of Calcium and Carbonate>

So I took some measurements of co2 by measuring dkH and pH in tanks with various plant loads. To my surprise the pH in all my stock tanks was 7.8+.
I have been racking my brain trying to figure out how this is possible given that I'm turning over the water 2 to 4 times per hour in each tank.
I'll also note that the co2 is much higher in the sump than it is in the stock tanks which is sort of predictable, but still surprising to me given the rate of turnover. I have a couple theories none of which I'm all that
convinced are the culprit. A. The sump is in a basement which might have higher levels of co2 in the atmosphere than on the main floor where the doors to the outside are constantly opening and closing, and thereby suppressing the pH in the sump?
<Mmm; not much suppression here>
B. The plants are photosynthesizing so rapidly that the pH can't drop?
<Possibly, but...>
C. Some mechanism in the substrate (detritus?), is breaking down at rapid enough rate to keep the pH high despite the turnover?
<The substrate/s themselves? Do you have much in the way of natural gravel, rock in these systems? A bit of Ozone/O3 produced by the Vectron/TMC UVs might be elevating the pH a smidgen>
Any other tests I can run?
<Mmm; I'd first and foremost be "testing the testers"... your kit/s it/themselves. I'd like to know separately what the GH and KH is here>

Is this a problem that may work itself out over time?
<Ah yes... the excess alkalinity should "be reduced" in time... unless you're inadvertently adding more than is being consumed by reductive processes here>
Would injecting co2 be advisable?
<Mmm; yes... given all else is "fine"...
IF it were my shop (we had three sets... I spent 14 years on the floor LFS); I'd be checking for ferrous ion as well... a common issue with chlorotic, otherwise poorly aquatic plants in captivity>
I worry about safety with the pH controller in the sump ( likely to remain there) when the pH is so different between tank and sump. Also if the pH can be so different, it seems safe to assume that my tanks with less plants may accumulate co2 whilst my original theory was that the co2 would be either gassing off as the water flowed through the socks and not accumulate and though I'd waste a lot of co2, I'd still be making it available for plants that desired it.
Thanks for your time, any other input beyond my specific questions is also welcome,
<Do you purposely add any source of alkaline earths, alkalinity here (other than the mixed RO/tap water)?
Bob Fenner>
Re: pH Control in Multi-tank System
Hi Bob,
Great to have your assistance.
<Glad to help... enjoy the modern "Sherlock" series and doing my own bit of it petfish wise on the Net as well>
Re: mechanical filtration. I just have the socks but they do get changed daily. The bio filter additionally has a large 6" thick coiled mesh filter as are used in pond filters. I also have a large carbon canister that runs
separately as needed. Anything else you'd suggest?
<Likely the 9 or more micron cartridge filters to help remove more of the muck/mulm... but, if you're happy with your water clarity... no biggie. The cartridges are a pain admittedly; requiring at least two sets, almost daily attention; more pumping, expense. And won't take out all pathogenic disease (even down to 1 micron)>
I did some more extensive testing and clearly have some issues but not the ones I originally thought. I'm blaming my pH conundrum on my pH pen which is calibrated but has a hard time reading the tank water. It instantly picks up 7.0 or 10.0 calibration solution accurately, but then won't read tank water without a battle, usually reading it around 7.8, but occasionally it reads closer to my Neptune probe which is more consistent with other testing methods and also calibrated. So I think your first suggestion, testing the tester, turned out to be the issue. Though, why it tests so sporadically in our system but tests the calibration fluid spot on every time I don't know.
<Artifactual... I'd get a cheapy Milwaukee... or just go back to colorimetric assay>

I tested sump and a sample tank separately and found them identical in all tests.
Re: Alkalinity not adding anything at present.

<I might well do so... again, the base reactions that will reduce the nutrients require these>
PO4- >5ppm (I'm not sure to what degree, as I ran out of reagent after running it through the colorimeter diluted in half and it maxes at 2.5ppm)(.4ppm in my tap water)
NO3- 16ppm
K- 750ppm (with RedSea pro test kit for reef tanks, not sure if translates to FW as this number appears a bit fishy, but maybe with the out of control phosphates, I'm getting potassium too?)
Hardness <1 dGH
Carbonate Hardness 2dKh
Ca - Undetectable (using red sea pro titration)
<Trouble... again, see the SeaChem line (real products... and miscible w/ all else you've got going):
yes; though these are labeled/for "reefs">
Based on what I'm seeing this is my action plan.
1. Increase my water changes further (at least short term) to get the phosphates under control
<Look into Lanthanum use here... once a week, pulsed>
2. Implement some preventative phosphate measure through manual detritus removal, reduced feeding
3. Begin supplementing iron to improve plant growth (and in turn hopefully further reducing phosphates)
4. Add co2 via the sump and test alkalinity (assuming here that as the pH drops the system will utilize tap water more frequently giving my co2 some dKH to convert)
Does this seem sound? Anything else you might advise?
Matt Johnson
<Just these for now. We'll be chatting. Bob Fenner>
Re: pH Control in Multi-tank System
Is the reef buffer vs. the alkalinity buffer from their plant or AquaVitro line preferred for any reason? I'm guessing either can be employed with success but curious as to your specific suggestion.
<Mmm; the reef product is a bit different (has more carbonate) and is cheaper in volume, per use...>
What is the best method for evaluating the quantity to dose?
<This may seem a bit wanky (because it is), but I'd mix in an ounce or two in some water and toss it in your sump
... How to relate this... the two gentlemen that were kind to be my master teachers (when I was getting my H.S. teaching credential) for chem. and physics would ask for a "pinch" or
"smidgen" of creamer, sugar when I made them coffee and tea... they penned tens of millions of copies of science texts...>
Am I shooting for a target dKH?
<A few units... again; try the ounce or two per day for now...>

What will be the impact on pH and should I adjust dose to minimize that impact?
<You may see a small run up in pH (a tenth of a point or so) initially, but it will "be gone" in a few hours>
I'm intrigued by the Lanthanum and looking forward to testing it out.
<Is a/the "magic ingredient" in commercial ap.s for eliminating HPO4 issues... cheap, reliable and safe>
Thanks again,

Hard Water to Soft Water.... Input on changing water chem. 5/28/14
I live in the Arizona desert. I have a 15 gallon tank with a 10 gallon sponge filter (the 10 gallon sponge filter is only temporary, until I get in the 15 gallon sponge filter I ordered). I got 6 neon tetras and 1 mystery snail coming in. I looked on the internet to see if my current filter could handle the fish and snail. It should be ok until I get the 15 gallon filter in. I searched on the internet and discovered the mystery snail would do fine with a ph of 7.5. The tetras would also do well at that ph level. And they are apparently compatible.
The only problem is the tetras need soft water, but I have hard water with a ph of about 8. I used a ph down solution.
<Which changes the pH but not the hardness.>
<<Actually... the addition of acids nicks away at hardness... and the buffers that ARE registered as, are actual hardness>>
Is this enough to make the water softer?
<No; if it was as easy as adding a few drops of some chemical, we'd all be doing it!>
I have no access to reverse osmosis water.
<Rainwater is the classic zero-cost alternative, but in a desert I appreciate that may not be an option.>
Could I use bottled drinking water or distilled water instead?
<Drinking water probably not; it's rarely, if ever soft water, though it may be softer than your tap water. Check it and see. Distilled water, yes.
By definition, distilled water has no dissolved minerals in it.
Nonetheless, aquarists have found RO is cheaper that distilled water, and your local marine aquarium shop probably sells RO water by the gallon. Do remember of course that few fish live in water with no dissolved minerals and your aim is usually to mix pure water (RO, distilled, rainwater) with a certain amount of tap water, aiming for a hardness around 5 degrees dH and a pH between 6-7.>
Are there any other ways to soften the water without stressing the fish and
<Do read:
Neons aren't that fussed about water chemistry provided it isn't too hard, and you could easily keep them at, say, 12 degrees dH, pH 7.5. More than likely a 50/50 mix of RO water and tap water will be about right.>
Thank you.
<Most welcome, Neale.>
Temporary use of ph down product?        5/28/14

Hi. It is me again. I am the one with the neon tetra and hard ph problem. As stated before, I hard water with a ph of 8. I need it to be at 7.0 for my 15 gallon aquarium. I do not have access to a reverse osmosis unit or rainwater. And I hear distilled water is a poor choice.
<Not really sure why anyone would think so, except for cost. By the time you've mixed distilled water with tap water to get the correct water chemistry, or added appropriate Discus Buffer instead, the differences
between distilled and RO water would be miniscule.>
And bottled water can get expensive.
Using peat is out of the question as I do not have it right now.
<Peat is very old school and unfortunately very unpredictable. You can get some peat granulate from companies such as Eheim and Sera that works quite well, and it's more convenient than regular peat. But I'd use it in a separate filter/aquarium to soften a batch of water, then add that water to your aquarium when it's at the right chemistry values. On the other hand, peat isn't really a sustainable resource, and we probably shouldn't be using it much/at all.>
I ordered a water filtration unit that will demonize the water.
<These chemical deionising using typically fit onto a hose from the tap and you slowly trickle water through some sort of resin inside a cartridge. Some sort of chemical reaction happens inside them that replaces the
hardness mineral ions with something else. Unfortunately they are horrendously expensive to use per gallon, being "used up" very quickly in hard water areas, and you virtually never see them for sale in the UK any
more. Reverse osmosis is much cheaper, which is why it's so widely used.
But avoid cheap systems, and don't touch any water softener that doesn't have at least one carbon filter built into it. Why? Because if dirt particles aren't trapped first, then the RO membranes will get clogged up
extremely quickly, dramatically reducing their usefulness. Although aimed at marine aquarists, let me direct you to this article:
There's a minimum specification for RO filters that makes sense; if your budget doesn't cover that, then you'll honestly find buying RO water from a marine aquarium shop much more economical.>
But it will not arrive before the tetras and the mystery snail I ordered.
Could I use ph down temporarily, at least until I get in my water filtration unit? Thank you.
<Welcome, Neale.>
re: Temporary use of ph down product?        5/28/14

Thank you Neale. All I have to work with at the moment, however, is ph down.
<I would not use; serves little/no purpose, comes with attendant risks, stresses. In short, fish don't feel pH. Apart from extremes of pH, only exceptionally does pH matter; example: sex ratio of Kribensis fry. But fish *do* feel hardness, and the way that affects osmotic pressure on their bodies. Would be much better for all aquarists to concentrate on hardness rather than pH. Unfortunately pH is an easier concept to understand, and cheap products for changing pH are available, tempting.>
I heard white vinegar can lower ph, but is not much better than ph down. I have white vinegar. Should I try that? Since it is all I have how many times a day and how much per gallon should I use ph down, or white vinegar, until I get my deionizer in? The deionizer might take about a week to get in.
<Not worth messing about with pH directly. Get your RO/DI system, produce pure water, mix with tap water (or Discus Buffer, as preferred) to produce water that is both soft and slightly acidic to neutral (10 degrees dH, pH 7 would be absolutely fine for Neons). Naturally, acclimate the fish to reduced hardness and pH in stages; set the tank up with the same water as your retailer (presumably hard water?) then do 20-25% water changes every day or two with the softened water, so that after a week or so they've had
time to adapt.>
Can neon tetras survive at a ph of 8 with our hard desert water?
<Neons can tolerate pH 8 without problems. Indeed, most Amazonian fish will thrive between pH 6 and 8. But Neons do not do well in hard water, and my experience of keeping them in hard London tap water is enough to convince me that it isn't worth keeping them thusly.>
Thank you.
<Most welcome, Neale.>
re: Temporary use of ph down product?        5/28/14

Do you have any idea how I can make my own reverse osmosis filter?
<Mmm; not really worth doing... Cheaper and more reliable to just buy one... for a few gallons per day use... On Amazon or Home Depot or such.
Bob Fenner>
re: Temporary use of ph down product?        5/28/14

Thank you Bob.
Would this work to reduce the hardness of hard water?        5/28/14

1. Get a small section of pvc pipe
2. Get Aquarium carbon
3. Get a poly filter pad
4. get a bucket
5. put piece of poly filter pad into pvc pipe.
6. place carbon into pipe about 2" deep.
7. rinse water through pipe until water runs clear.
8. Place bucket under pipe and run water through pipe again.
9. Catch clean reverse osmosis water in bucket.
I used to this with saltwater water preparation. Will it help reduce hardness in freshwater?
<Might help a little bit... best for you to rig all up and just try it out... However; best to have you search, read on WWM... about the collection of rain water (in season), the use of plants (best Ceratophyllum)... as means... use of plants period, shading of your pond if the concern is algal control. B<>
Re: Will this work to reduce hardness of hard water? More blather     5/29/14

Ok. I got my tank filled to about 2 inches from the top of my 15 gallon tank. I used the Arizona desert's hard water. I filtered all but 1/4 of the water through the method I mentioned earlier. It has a 10 gallon sponge filter until I get in a 15 gallon filter I ordered. 6 neon tetras, 1 mystery snail, and 2 Anubias petite plants are going into the system. Is the filtered water now at hardness the neon tetras can survive at? At least until I get my deionizer filter in.
<.... how would anyone know? Testing>
re: Will this work to reduce hardness of hard water?
Re: Will this work to reduce hardness of hard water? More blather
I asked on yahoo answers website. Got 2 answers back. They said it likely did not work. One of them suggested it might have raised the ph! Argh! I am so frustrated right now. All I need to know is, will the neon tetras survive in hard water for about a week? Just until I get my filter in. And what, if anything, can be done to lower hardness without peat, RO, or going to the store and purchasing special water. We have unflavored bottled drinking water. Would that help any? Thank you.
<There is no magic way to soften hard water. Aquarists in the southeast of England live with "liquid rock" water and have been wrestling with this issue since the 1920s. If there was a "magic potion" you could add to the water, we'd be doing it, trust me! There really are just two options that have proven economical. One is collecting rainwater. Cheap, easy to do, but likely not practical in a desert. The second is to use RO water. All the alternatives have too many flaws or expenses. Peat works for very small quantities, but becomes expensive for large quantities and it is always difficult to predict how quickly a certain amount and brand of peat will work. It's a good approach for hobbyists who like fiddling about, who have
small water demands (Killifish breeders for example) and who can make the water separately in a basement or garage, ready for use as/when required. Ion-exchange resin "filter" cartridges that attach to drinking water taps can also work, but they're insanely expensive for large amounts of water, and fell out of favour almost as quickly as they appeared. If neither rainwater nor RO suit, then best to choose fish that enjoy your water conditions. There are many small fish that do. Check out the genus Micropoecilia for example; there are lots of small colourful fish in this genus that need hard water (even salty water) to do well. Hope this helps,
re: Hard Water to Soft Water.... Input on changing water chem.

Thank you Neale.
<Most welcome.>
re: Will this work to reduce hardness of hard water?

Thank you Neale. However, I have neon tetras already shipped to me. Too late to send them back. Oh dear, I made yet another mistake! I am so mad at myself. Will they survive in hard water for 7 days or so, when my deionizer will come in?
<Yes, they will be fine. Cheers, Neale.>
Can neon tetras live in hard alkaline water for 7 days?

<Oh yes; indeed, many can/do live in such for months, years. In the old says of the hobby, Neons could even do well in moderately hard, slightly basic water chemistry. But the modern farmed Neon is plagued with weaknesses and diseases ("Neon Tetra Disease" is now, I feel, a catch-all name for premature death rather than anything more specific). They're surely bred in soft, acidic, dark water conditions, but by the time they get shipped to the retailer, they've likely been moved into harder water conditions. Generous use of antibiotics along the way is probable.
Long-term success with this species seems elusive nowadays, and I personally don't consider Neons (at least not the ones sold in the UK) to be worth investing in. Cheers, Neale.>
Liquid co2 and water hardness
Re: Will this work to reduce hardness of hard water?
My fish need soft water. My water is hard. I need to lower the hardness of my water. I hear injecting co2 into the water can lower hardness in water.
Is this correct? If so, could I use a liquid co2 supplement instead of co2 injection to lower the hardness in my water? Thank you.
<Injecting CO2 into water creates carbonic acid. So again, this will lower the pH and use up (lower) some of the carbonate hardness. What it will not do is lower the general hardness, and therefore does not create soft water.
As we've stated now several times, there are no magic ways to create soft water. If there were, we'd all be using them. Your options are essentially rainwater and RO/DI water. Choose one. How else to explain this? Think about losing weight (without surgery). Two ways. Increase exercise so your calorie consumption per day goes up. Secondly, eat less food, so your body receives fewer calories. That's it. That's all there is. Eat less, do more exercise. Lots and lots and lots of other tips and tricks and pills
mentioned on the internet, but none of them work. Make sense? Cheers, Neale.>
re: Liquid co2 and water hardness     5/29/14
Thank you so much for your time and patience Neale. It all makes perfect sense now. Thank you, thank you, thank you!
<Most welcome. And trust me, as an teenage aquarist growing up in southeast England, I was desperate for a cheap and easy way to soften water! I would also mention that hard water isn't necessarily bad. Indeed, can be a blessing in disguise -- literally rock solid water chemistry for a start! Just avoid those tetras than need soft water. Skip Neons, Cardinals and Lemons for example in favour of Penguins, X-Rays and Emperors, none of which will come to harm even at 20 degrees dH, and X-Rays can/do tolerate
even higher hardness in the wild, supposedly even slightly brackish conditions. Cheers, Neale.>

pH water chemistry question     5/3/13
Hello I'm hoping you can help me resolve a problem.  I have a 10 gallon planted tank with a Betta.  This is a low light set up with 2 -10Watt CFLs.
I dose fertilizers including Excel 3 times per week.  Tank has been set up for 1 1/2 months. In setting up my tank I decided to mix distilled water 75% and tap 25% to lower my GH.   My tap is GH16 and I didn't want to be limited by this. My formula ended giving me GH5 and PH7.6. Over a three week period I tested the GH and it was pretty constant at GH5-6. I didn't bother testing the PH as I assumed it was in line also. When I was acclimating my fish I tested all my water param.s to compare to the water my fish came in. To my surprise my PH tested at 8.2. How can this be?
The good thing is my Betta's water tested at 8.0, but I'm concerned about the large swing. I did more testing and the result is that during the night the PH would be high and during the day the PH would be normal. I'm concerned because high PH fray Betta fins and I know they need a stable PH.
<Slight pH changes, say from 7.6 to 8.2 over a 24-hour cycle, are not a problem; indeed, they happen in the wild all the time. e.g., in garden ponds.>
I've inquired else where and was told this is normal, but I'm concerned. 
Can I add something to the water to stabilize the PH?
<No real need.>
I've read about different products, but they indicate they will increase the hardness.  Doesn't this defeat the point? 
<Depends what "the point" is. First, check the carbonate hardness, measured in degrees KH, as this is the stuff that mostly inhibits pH drops. It's not the same as general hardness (GH, measured in degrees dH). If your carbonate hardness is very low, then pH will drop; conversely, if carbonate hardness is very high, it will probably keep the pH around 8, plus or minus a little. My guess would be that you have carbonate hardness around 10-15 degrees KH out of the tap, and so you should still have 2-4 degrees KH in the aquarium assuming your 3:1 ratio of pure water to tap water. You may want to use a neutral pH buffer, but to be honest, I wouldn't bother. If the fish is basically happy, I'd not be worried; indeed, I'd not even faff with the 3:1 ratio, and would simply mix DI water with tap water at a 50/50 ratio, which is plenty good enough for farmed Bettas, and being cheaper because you're using less DI water, you can afford to do more water changes.>
I'm new at fish keeping and water chemistry.  Thank you!  Donetta
<Welcome, Neale.>
Re: PH water chemistry question     5/4/13
Hello Neale, I so appreciate you answering this question!  It's been really bothering me and it takes a load off.  I am going to change my RO formula to 50/50, I agree that works better for me.  One more question if you don't mind.  My Betta had been happy, however last week I noticed that some of his fins started to split and his tail developed pin holes and was getting shorter and shorter.  I read that the issue is almost always poor care/water quality, however I couldn't imagine that because I usually do 2X weekly water changes because of the live plant start up.
<Non-zero ammonia and nitrite levels during the cycling process (or of course afterwards) are common reasons why fish become stressed. In turn, stress weakens their immune system, and that allows opportunistic bacteria to invade the fin and skin tissue, starting the process of Finrot. With this said, because Bettas have unnaturally long fins, they are especially prone to physical damage as well, such as clumsy netting, bounces during the trip from store to your house, abrasions caused by sharp rocks and ornaments, even excessive suction from filters (you should use an air-powered filter on a Betta tank rather than an electric filter). Rapid pH changes don't normally cause Finrot directly, though repeated water chemistry changes can stress fish beyond their ability to adapt, and that could allow something like Finrot to get started. But more normally rapid pH changes produce more obvious signs of stress: nervousness, jumpiness, gasping at the surface, and other such signs of a fish that wants to get out. Provided your tap water isn't mind-blowingly hard (above, say, 20 degrees dH, pH 8) then there's no real need to mess about with water chemistry for domesticated fish such as Bettas. Indeed, you could argue that a stable, if high, pH around 7.6 would be better than trying to maintain, clumsily, a more "natural" pH around the 6 to 6.5 mark that actually ends up changing every day.>
So I thought maybe it could be PH swings, now I know differently.  However, I realized that poor water quality came from my water sprite plant that rotted.  However, I was stumped by this because only the base (mother plant) died and the floating part had and created tons and tons of baby plantlets and I've had to cut it back every week.  Anyway, so much to learn. 
<Water Sprite is easy to grow, but yes, it's a good idea to crop it back regularly. I'd warmly encourage you to try it again, but do get true Water Sprite (Ceratopteris thalictroides) rather than a lookalike species like Water Wisteria and bear in mind that all floating plants need some space between their leaves and the tank lights, at least an inch, preferably more. I happen to find Amazon Frogbit works much better in tanks with limited space under the hood; it's an easy to grow plant in other regards too.>
So, I pulled up the plant and cleaned everything out really good.   Last Saturday I moved my Betta to the 1.5 QT tank and have been doing 90% water changes with 1.5 tsp of salt.
<I wouldn't bother with the salt, to be honest; at least, not once the fins are better.>
His fins stopped receding and the pins holes have mended even though I can tell the healing in not complete.  There's still a tiny split and the fins have not grow back yet.  My question is can I move him back to his regular home since now I know the problem?
<Sure, provided water chemistry is stable and water quality is good.>
Another thing I should mention is he clamps his back tail at times.  Is this part of the fin rot?
Also, under his chin it looks a little more smooth than usual seems like it should be more scaly.   He hates it in that little tank and definitely he is not as active in there.  If I move him back is twice a week water changes enough at 15% each?
<Or some multiple thereof, yes. For a single Betta in a 10-gallon tank, a 25% water change every week or two should be ample. Remember not to overfeed though!>
Also, if I move him I will have to decrease the salt?  I believe it will kill my plants.
<May do so; depends on the plants.>
I'm scared to do this, unless possibly only 1 tsp for the whole tank.
<One teaspoon per 10 gallons is trivial, and will have zero effect on either plants or fish. I know some Betta people are wedded to this addition of salt to their systems, but there's no real evidence it helps, and at this level, it can't possibly stress or kill pathogens like Finrot bacteria (which do, after all, live in brackish and marine aquaria!!!).>
Also, I have two crazy Oto cats in his big tank that helped with the algae, but I'm thinking it's best to take them out.
<Ah! The plot thinnens! Otocinclus are NOT as harmless as they seem. Some specimens are known to nibble at the flanks of slow-moving fish. I would not keep them with a Betta; if you must have tankmates with a Betta, choose something totally harmless, like Corydoras or Whiptails.>
They are so hyper! I know there are tons of threads on this issue, but I'm hoping to get an answer for my set up.  Your site is truly amazing.  Thanks for being so willing to help.
<Most welcome, Neale.>
Re: PH water chemistry question     5/4/13

I forgot the picture!
<Ah yes, a Betta that's been through the wars a little. Otherwise looks sound though, so should recover. See previous message for suggestions on this. Cheers, Neale.>

Re: PH water chemistry question     5/6/13
Thanks again for your reply!  I really appreciated the tip on water sprite
<Glad to help. Cheers, Neale.>

PH questions, adjusting, FW     7/25/12
Hi there,
if I ever need to raise my freshwater tank PH I've read crushed coral will do the trick, unfortunately not easy to find in Mexico, would a common white coral (small complete piece) help?
<Mmm, not likely... probably too "hard" as in insoluble... What are you trying to do w/ elevating the pH... If not too much up I'd just use baking soda (Sodium Bicarbonate...). Read here re:
and the linked files above>
also, I've put 2 mangrove roots (like the image attached) in my tank, I heard it helps maintain the PH Angelfish need, but my water is way too yellow and dense, should I leave them even if I have a 6.5 to 7 PH?
<Yes... if this is fine for your other livestock; use activated carbon to remove the yellowing... Bob Fenner>

Freshwater water chemistry issue     4/19/12
Hello and good day.
<And you>
I have a very short and to the point question I am hoping you can help me with.  Thank you in advance for any help you can provide.
My issue.
My freshwater aquarium has a PH of 7.4 however it only has a dKH of 4.
<Mmm, this should be fine...>
 I would like to raise the dKH to around 6 however I don’t want to raise the PH much more.  Can you offer and advice on how I can make this happen?
<Mmm, you could add a bit of baking soda... Please read here: http://www.wetwebmedia.com/FWSubWebIndex/fwhardness.htm
perhaps a bit of Neale's Rift Lake mix DIY prep.>
All other parameters (nitrate, nitrite, ammonia) are all excellent.  The tank is 72 gallons with only 7 fish right now.  I ultimately would like to keep live bearers but I know the water currently in the tank is way to soft for them thus why I am trying to raise the dKH.
Thank You
<Welcome. Bob Fenner>

Can't get my pH up . . . from Dallas   9/11.5/11
Hi Neale, <Nancy,>
Hope things are going well there for ya'll. The hurricanes and tropical storm systems which are skirting the US coast seem to be heading towards the UK an awful lot. Hope everyone is doing okay.
<Everything is just fine; thanks for asking!>
The best water testing results I have been able to get (and it is with the Tetratest EasyStrips 5-in-1 strips) follow:
Nitrate: 25 ppm Nitrite: 0 ppm GH: about 250 ppm KH: 100 ppm pH: 6.4
<Actually sounds pretty darn good for soft water fish, like those from the Amazon and Southeast Asia. So provided you avoid things that need hard water, like Central American livebearers, you've got lots of potential here. Indeed, some would KILL for this sort of water chemistry!>
Temp: between 76.3 F and 77.6 F
(other specs are in my original e-mail which follows)
Since my first e-mail, I have added 4 "Black Skirts" (they act like tetras to me)
<Is what they are.>
and 4 more of the Von Rio tetras. I also added a variety of plants, which are all well loved by the Silver Dollars.
<Yes; herbivores, like all the Piranhas to some degree (Silver Dollars are piranhas).>
All of the Black Skirts seem to be doing well. I have lost two of the Von Rios, but the one I have had since March is doing well, so it may be a problem related to shipping in the terrible heat we have been suffering. I add Melafix for three days whenever I add new fish.
<Bob F. would probably recommend against doing this. Melafix has a distinctly mixed reputation around these parts.
My thoughts are that as a preventative, when fish are injured but not actually infected, it's perhaps worth using. But I wouldn't use it once fish are obviously sick, and I probably wouldn't add it to a tank alongside uninjured new fish.>
My 3 albino Corys, one fairly small adult angel,
<Do watch the Black Skirt Tetras here -- they can nip at Angels, Gouramis and other such fish.>
and three of the four silver dollars are doing well. The male silver dollar who had his tail and fins eaten down by the dominate male has even grown back all but one pectoral fin -- even his tail which was eaten into the flesh!
<Glad he's happy again. Many of the piranhas behave this way, and may actually be more aggressive when young than when they mature. In any event, it's worth bearing in mind they're intensely hierarchical, and the bigger the group, the better they'll behave.>
The dominant male silver dollar has not been the same since the night he was startled awake and rammed into the side of the tank so hard you could hear it in the other room. This happened about a month ago. Even though I have been told that silver dollars do not have scales, I saw what appeared to be several relatively large scales drifting in the water at the time.
<Are scales; these fish are not scaleless.>
I expected to find him dead the next day. But, he made it. Since that time, he is acting his normal, dominate male self. However, beginning the next morning, he has had a "blush" over his lower gills and across his nose, between his eyes which is the same color as the red on the edge of his fins and tail. This coloring stays while the dark stripy spots come and go, which I have assumed are breeding markings since they coincide with his more aggressive behaviors. Should I be concerned? If so, what do I do? He is about 4 years old.
<Would not do anything. Sometimes physical damage affects the nerves used to control body colour, and you'll find injured fish that get better but retain odd dark or pale patches for life. If the fish otherwise looks healthy, and doesn't show signs of Finrot or Dropsy or anything like that, I'd just leave things be.>
Thanks so much for your help and the education.
<You are most welcome. Cheers, Neale.>

Adjusting pH in a 220 gallon planted Discus Aquarium 7/19/11
First off, you have a great website with a plethora of excellent information for hobbyists and your information is very helpful!
<Glad you've enjoyed the site.>
I have a few questions I am hoping you could help me with. I will pose the questions first, then give you my background info:
1. How do I adjust the PH of my aquarium water from 7.4 to 6.5 without adding chemicals that would harm the plants or increase water hardness?
<You can't. Adjusting pH is putting the cart before the horse. It's crucial you understand this. Rainforest streams have an acidic pH *because* these waters have a low carbonate hardness, so decaying plant material is able to pull the pH downwards. In rainforest streams sheer volume prevents extreme pH drops in most circumstances, but in the confines of an aquarium you need to provide some sort of buffer that keeps the pH from dropping below, say, 6.5. This is best done using a commercial pH buffer. But note that these "pH down" products are designed to steady the pH *after* carbonate hardness has been lowered. So you need to lower the carbonate hardness first, and steady the pH second.>
2. What is the minimum GH/KH before I would run the risk of PH acid drop?
<Below a carbonate hardness of, say, 3 degrees KH, you will find pH will be unstable between water changes. So a different chemical is used to buffer the pH, typically phosphoric acid. This is the main ingredient in commercial pH buffers. Unfortunately, phosphoric acid creates phosphates under certain chemical conditions, and phosphates can trigger algal blooms.>
2. Will adding RO water into the mix of regular well water eventually bring down the PH?
<No. All lowering carbonate hardness will do is make water pH less stable.
If you have an initial carbonate hardness of 3 degrees KH, you may well start at pH 7.5, but a week later find the tank has a pH less than 7.>
3. What kind of algae eating fish could I use to control algae that wont be harmful to the discus or eat the plants? Algae is growing on the surface of the plants and it'd be nice if I could eliminate it. I've been thinking some kind of Pleco but not sure what kind.
<Plecs generally have no place in the Discus aquarium. Among other things, they are messy, they damage plants, and, in certain situations, they suck on the sides of Discus, causing them stress. Better choices are things like Hypancistrus, but these eat very little algae being more or less carnivorous in tastes. In any event, Plecs have minimal impact on algae, so instead you need to concentrate on getting the ecological balance right between plants, light intensity, and nutrient content of the water.>
For the background info, I have well water with a 14Gh and 9KH and a PH of 7.6.
<A bit hard for wild-caught Discus, but adequate for farmed species, particularly if you mixed about 50/50 with rainwater or RO water.>
I am using EcoComplete substrate for planted aquariums and my system is a 220 gallon wet dry and I have a UV unit inline. I recently purchased an RO unit and I've been adding RO water into the tank which has well water which has a PH of 6.4 in hopes of reducing the PH and the hardness.
<Carbonate hardness may go down, but that doesn't automatically pull down pH.>
The hardness is coming down as I add the RO water but the PH has changed very little (down to 7.4).
<As predicted; see above.>
What I would like to do is get the water to the proper PH/GH/KH for the discus in hopes of eventually getting them into breeding condition and to maximize their growth.
<Remember, pH is relatively unimportant, despite the fact beginners tend to obsess about it. On the other hand, general and carbonate hardness are both important, and in the case of Discus, should be somewhat low. Around 10 degrees dH, 5 degrees KH would be more than adequate for farmed Discus, even if the pH was around 7.5. Even better would be pure RO water turned into safe aquarium water through the use of commercial Discus buffering salt mix, e.g., Seachem Discus Buffer, to create the proper stable pH and mineral content.>
Any info you could provide would be most helpful. Thanks!!!
<Cheers, Neale.>
Re: Adjusting PH in a 220 gallon planted Discus Aquarium   8/4/11

Thanks for the information. It has been very helpful.
<Glad to help.>
I now have the tank 7.5 GH and 5KH. The PH is at 7.4.
<Sounds excellent.>
I do have the buffers to lower and stabilize the PH but I am reluctant to use them as the labels say not to use with live plants.
Will these buffers harm the plants?
<No idea. Never heard of this being a problem. Possibly worth calling/writing to the manufacturer or visiting their web site. In any case, your pH is fine now, and if you can keep the pH there between water changes, a buffer might not be necessary.>
Will the discus be able to successfully breed at this PH?
<Farmed types, yes.>
I would prefer not to use the buffers if I don't have to.
<Agreed, but the main thing is the pH is steady. If you have the pH drop or rise far from 7.4 across the week, you may have to use the buffer no matter what.>
Any advice would be most helpful.
<Cheers, Neale.>
Re: Adjusting PH in a 220 gallon planted Discus Aquarium 8/5/11

<Hello again,>
I wrote Seachem about phosphate buffers and planted tanks and I am forwarding their response to you fyi with their permission:
Thank you for your question. While Neutral Regulator and Discus Buffer will not harm plants they may not be best suited for planted aquariums. While phosphate based buffers are great for most freshwater aquariums, when combined with fertilizers and high light typically found with planted aquariums, they can encourage algae growth. That is why Seachem developed Acid Buffer and Alkaline Buffer. These buffers do not contain any phosphates and are much better suited for planted aquariums. I have attached links to these two products so you can read more about them. If you decide to use the Neutral Regulator or Discus Buffer, just keep an eye on your water parameters and make sure you keep the organics down. I have known many people that kept beautiful planted tanks with phosphate based buffers but you do have to be careful. Any time there are excess phosphates and organics along with high light you can end up with a nasty algae bloom. Please let us know if you have any additional questions.
<Very interesting. Yes, there is a supposed connection between phosphate and algal blooms, but I'd have thought algae is more of a problem in tanks *without* plants than tanks with them. After all, in a well planted tank, the plants outcompete algae, and may even have some allelopathic effect. I've yet to see a serious algae problem in a balanced planted tank, even ones with very messy fish; but algae problems in tanks without plants are very common, even normal. In any case, an interesting argument worthy of consideration.>
Thanks for all your help....
<And thank you for this follow-up. Cheers, Neale.>

Lowering pH   12/30/10
Until recently I have always matched my fish to the water conditions, but I wanted to try something a little more challenging. I am considering keeping some Mikrogeophagus ramirezi in a species tank, but here is the problem. My tapwater is crunchy and alkaline (pH generally around 7.8 in my livebearer tanks). I believe these fish prefer soft acidic water, especially for breeding.
<They require soft water simply to stay alive! In anything harder than, say, 5 degrees dH they tend to be extremely delicate and disease-prone.
Once you have water that soft, fixing the pH at around 5.5 to 6.5 shouldn't be too difficult. But please do understand that pH is something beginners focus on, whereas the fish are interested in hardness. Expert fishkeepers raise or lower hardness as required, and then fix the pH as necessary. In other words, hardness is first in importance, and pH a distant second.>
Without going the route of using DI or RO water, and without using CO2, what are my options for bringing the pH down to around 7?
How much impact can I expect peat to have on pH?
<In hard water? Minimal.>
What do you think about adjusting the pH with muriatic acid before adding the water to the tank?
<Pointless. Any lowering in pH will be unstable, and in any case does nothing about reducing the total dissolved solids in the water, i.e., the general as well as carbonate hardness, since acids merely react with the carbonate hardness. So what's the point? Use pH buffers to FIX the pH at, say, 6.0, only once you've lowered the general and carbonate hardness levels. In the case of Ram Cichlids, the aim is 1-2 degrees dH, 1 degree KH, and a pH between 5.5 and 6.5, with the lower end being preferable.>
I'm not sure how else I could overcome the hardness buffer.
<I have rock hard water and mix it with rainwater collected from the roof. Cheap, easy, and extremely "green" in terms of environmental impact. RO and DI units are very expensive in terms of set-up, usage, and water wastage.>
While I expect tank-raised rams could probably adapt to living in my water, I doubt they could breed in it.
<Actually, tank-raised Rams will probably be dead within 6 months in your water. Look instead at the infinitely better congener, Mikrogeophagus altispinosus. While it won't thrive in rock hard water, it does just fine in moderately hard, slightly basic water, say 10-15 degree dH, pH 7 to 7.5.>
Rick Novy
<Cheers, Neale.>
Re: Lowering pH   12/30/10
Thanks Neale,
Alas, that's what I was afraid of. Rainwater is too unreliable in the desert where we average 7 inches a year and often get far less. I'll check into the other fish you mentioned.
<Ah, I see. In England, rain is certainly not unreliable! Do look at the Malawian and Tanganyikan cichlids if you need something small and hard water tolerant. Some of these are charming fish, Julidochromis ornatus for example being every bit as fun as Ram Cichlids and far easier to keep in hard water. It doesn't uproot plants, is only mildly territorial, and while predatory it will ignore fish above guppy size, making it a potential community resident. Cheers, Neale.>

pH and KH query (re. goldfish) - FAO Neale if possible, thanks! 11/18/2010
Dear Crew,
I have a question which I hope you can help me out with. I've recently been getting to grips with the complexities of pH and KH for my goldfish, thanks to the helpful articles on your site. However, I've run into a problem which I haven't been able to solve by reading. The tank pH is presently 7.6-7.8 and the KH is approximately 5 (raised from very soft, acidic city water over the past few months) and my problem is that the KH is still too low. From my reading, I understand that it should be around 6-7. However, raising the KH any further with the Malawi salts I've been using will also raise the pH again (and it's already borderline too high). I've read a lot on WWM, but while I've found a great deal on lowering pH, it's usually to achieve a pH of around 6 (which is of course too low for goldfish). How can I raise the KH while fixing the pH at 7.5 or thereabouts?
I'd really appreciate any advice from you, and thank you very much in advance for your time. I know you get this a lot, but WWM is my Bible!
Best wishes,
<Hello Sarah, and thanks for the kind words. The Malawi salt mix can be tweaked up and down as required. Reduce the Epsom salt to lower general hardness, and reduce the sodium bicarbonate to lower carbonate hardness.
Reduce or skip the marine salt mix to reduce both general and carbonate hardness slightly. Now, note that carbonate hardness is important primarily in how it steadies the pH. If you have a pH of 7.6-7.8, and it stays there from one week to the next, then there's no need to raise the carbonate hardness further. In an aquarium, you can't easily raise pH without raising carbonate hardness. Furthermore, there's a complex relationship between pH, carbonate hardness, and carbon dioxide concentration. So pinning down
precise values is tricky. Instead, just go by the "feel" of the thing -- if the pH is steady between 7.5 and 8, and the carbonate hardness is within the tolerances of the species being kept, then you've created the hard, basic water conditions goldfish, livebearers and other fish like these enjoy! Cheers, Neale.>
Re: pH and KH query (re. goldfish) - FAO Neale if possible,  11/18/2010
Dear Neale,
Thank you very much for your quick reply; it's much appreciated. It sounds as if it'd be best to keep things stable, then; pH and KH are both within acceptable limits, and I've finally achieved pH stability with water
changes, so it's all good. As it happens, I buy pre-mixed Malawi salts at present (taking heed of the note in the WWM article that beginners should avoid mixing their own at first) - however, I'll save your email for future reference as that's very handy.
Many thanks again for your help, and enjoy your weekend!
<Glad to help, Sarah. Yes: provided the pH is stable, you don't need to worry about the precise carbonate hardness, assuming the water is broadly within the tolerances of the fish being kept. Have a good weekend yourself, Neale.>

pH confusion, FW, GF tank   2/9/10
<Hi, Angela. Melinda with you here today.>
I'm very confused with the pH in my 20 gallon goldfish tank. I tested the water from the tap and the pH reads between 7.6 and 7.8. I have tested a few times from the tank and it shows 6.0 (or "yellow") on the API test. I
use NovAqua+ and Amquel+ to treat the water. Could that be affecting the pH? I'm thoroughly confused as to why it's so low. Thanks for your help!
<Do you test KH at all? Please read here:
http://www.wetwebmedia.com/FWsubwebindex/fwh2oquality.htm. This article was so useful to me, and completely cleared up my confusion about water chemistry. I use this mix with every water change on every tank. I just love the stability and neutral pH that it gives me (I'm sure my fish do, too!), and this salt mix is so cheap and easy to make that it's no problem to use it regularly. KH and pH totally confused me until I read this article (okay, I read it a few times, but I'm a literature person, not a science person!). Basically, the hardness of your water is going to determine how elevated and steady your pH is. If your water is really, really soft (my carbonate hardness routinely tested at 0!) then you're going to see the problems you're seeing with pH. Raise KH, and you'll find pH is steady and will more closely match what's coming out of your tap (mine stays at 7.2). The waste that your fish excrete causes the water to become more acidic over time, as well, so if you're not doing plenty of water changes (20 gallons is pushing it, really, even for just one goldfish), then this can be a problem, as well. I think between these two issues, you'll find the remedy to your problem. I have never heard of either of the products you mention affecting pH, but have read that they can cause false positives on Ammonia tests, so I stick with Prime. In any case, please write back if you have any questions.>
Re: Ph confusion  2/9/10
Thank you very much for your response! I have 2 goldfish in the 20 gallon so I make sure that I do small water changes about every 4 days. So it's ok to use marine salt with goldfish?
Also, if the pH comes out normal out of the tap and I add the salt mix, will it just keep it neutral, not raise or lower it?
<Right. Like I said, mine stays at about 7.2 all of the time with the mix I use (the community recipe). Go slowly, adding per the directions in the article, and when you get to where you want to be, KH and pH-wise, add just
enough with each water change to keep the amount pretty much the same in the tank. If you do a five gallon water-change, then you'd add 1/4 of the mix for the entire tank. Just keep up with how much you've got in there so that when you get where you want to be, you know how to keep it that way.>
Thank you again, this has been so confusing to me. I try to do everything right but I had no idea how delicate water chemistry can be!!
<You're welcome. I think that this mix really takes a lot of the guessing out of chemistry -- it sort of "fixes" everything without much work at all!>

Low ph... I think this is a FW Q, situation, RMF -- 1/28/10
I know that crushed coral will raise my ph but I don't know how much to add to a 55 gal tank with a ph level of 6.2
<It won't to any appreciable degree at all, You need to read:
http://www.wetwebmedia.com/marphalk.htm. There are too many different factors that affect pH for a substrate to be 'the answer'>
Can you tell me how much?
<This won't work, and this substrate (crushed coral) is abrasive. I would use fine aragonite sand here instead, about 1 inch depth. Please read:
Hello Kamal, I am writing further to you as I think you have a freshwater system, not marine. Please read here:
and write back to us if you have further concerns, questions. Bob Fenner
Re: More re: low ph  1/29/10

<Oooo... I should have thought that this could have been a freshwater system.. My apologies here. Simon.>
<<No worries. BobF>>

Lowering pH while maintain a high KH with phosphate free pH lowering Products 12/16/2009
Hi WWM crew,
I have posted this question on the WWM forum and was recommended to post the question directly to the WWM crew.
I have been researching this topic for a while and am wondering if anyone could tell me what chemicals I could use to force a low pH while keep a high KH for biological filtration and maintaining stable pH.
<None. Anything that lowers the pH will consume carbonate hardness.
Carbonate hardness is by definition an alkaline buffer.>
I know a lot of products use acetic acid (or sodium acetate) to create a low pH buffer.
Phosphate based buffers such as orthophosphoric acid and sodium bi-phosphate are by far the strongest and most reliable acid pH buffers and work easily and effectively but for planted tanks, marine tanks or any tank you don't want phosphate in, these are not able to be used.
<Perhaps. Can't think why you'd want to lower pH in a marine tank. As for phosphate in freshwater aquaria, there's no real link between phosphate concentration and algae problems, any more than between high levels of nitrate and algae. Yes, eutrophication is one reason for algae blooms, but there are plenty of tanks with high levels of both and no algae problems, and conversely keeping near-zero levels of nitrate and phosphate doesn't automatically prevent algae problems either. So while this explanation was often stated in the past with absolute conviction, I think the hobby has moved on now>
I have heard of Seachem's acid buffer being a sulphate based compound, sodium bi-sulphate perhaps?
<Will still use up carbonate hardness.>
I have read that these kinds of products "force" a buffer that creates a low pH by the product being oxidised into CO2, which then lowers the pH but doesn't affect the KH value.
<Eh? Doesn't sound like science to me. If you add acidity to an aquarium, it will react with any basic chemicals it can find, whether carbonate
hardness or otherwise. You don't get to choose which ones react.>
Could you shed some light on this subject, the theory behind it, and what products I could potentially use (apart from Acetic acid) to lower the pH without affecting the KH?
<The real question is "why"? If you have a tropical community tank, then a pH of 7.5 is not just acceptable but ideal. This is the optimal pH for biological filtration in freshwater aquaria, and tolerated by almost all community fish. As should be clear to you from your reading (and if it isn't, I'd caution you not to mess about with water chemistry) you never, ever change pH directly. Fish prefer a stable pH, and rarely does the actual pH value ever matter. In those cases where you must have a strongly acidic pH -- Pikeheads, Chocolate Gouramis and Ram Cichlids for example -- you'd also be providing extremely soft water, and likely not using biological filtration either, since such filters don't work at the required pH 5.5-6. If you had such soft water, lowering the pH would be TOO EASY, and you'd be using a pH buffer to prevent further drops between (very frequent) water changes.>
<Cheers, Neale.>

Re: Lowering pH while maintain a high kH with phosphate free pH lowering Products  12/21/2009
Hi Neale,
Thank you for the reply.
From the reading I have done, it is pointed out that Carbon dioxide in water will lower the pH but not the kH of the water.
<It can't do one without doing the other. CO2 in water forms carbonic acid; carbonic acid reacts with sodium bicarbonate (one type of carbonate hardness mineral) and you get an acid/base neutralisation reaction. You
probably remember this from school: acid + base = some type of salt + water.>
wouldn't this then maintain a stable kH (and therefore a stable pH) but lower the pH to the pre-described level if enough CO2 was added, and therefore let me maintain a higher kH, but a set lower pH than would usually occur at a higher kH value?
<By definition, CO2 can't maintain a stable carbonate hardness. As for lowering the pH, that will only happen once carbonate hardness drops sufficiently.>
In this case, if I was adding acetic acid like I mentioned before, that is then metabolised into C02, wouldn't this do the same thing?
<Not that I'm aware.>
I believe this is how the Seachem Acid buffer/alkaline buffer combination works, but because of all the conflicting information on the net, it is hard to determine what the actual process is?
<In water with zero hardness, i.e., pure water, you can add roughly equal amounts of both acid buffer and base buffer.
This provides buffering capacity in both directions, preventing rises or falls in pH. In water with high hardness, specifically high carbonate hardness, you reduce or leave out the base buffer completely, since the
carbonate hardness (the alkalinity) is doing that job automatically. Since aquaria tend to become acidic, for most people, the only buffering that matters is that which works *against* acidification, hence the importance
of carbonate hardness.>
I am trying to find out how this process works, and what substances I may be able to use other than acetic acid to lower my pH without effecting my kH.
<You really can't. In low pH aquaria, e.g., one where you want the pH at 6.5, you have little or no carbonate hardness. The danger here is that pH can (and will) drop very quickly between water changes given the chance. So
you need to add a low pH (and acidic) buffer that inhibits further pH drop below the preset value. But unless you have a darn good reason to set up an aquarium at a pH below 7.0, it isn't worth doing this. Biological filtration works better above pH 7.0, and maintaining a steady pH in an aquarium with some carbonate hardness is a lot easier.>
Thank you for your time.
<Cheers, Neale.>

Re: Lowering pH while maintain a high kH with phosphate free pH lowering Products   12/22/09
Hi Neale,
Sorry to bother you again but I only have one more question.
<Fire away.>
What would be the difference with sodium bi-phosphate? in my experience it lowers pH but does not affect the kH, allowing you to maintain a higher kH value and a lower pH, what would be the reaction that takes place here?
<Sodium biphosphate is the standard pH 6.5 buffer on sale in aquarium shops. Added to water it dissociates into phosphoric acid, and that is what lowers the pH.>
Would there be any other chemicals that would perform the same as sodium bi-phosphate, providing an acidifying affect without having to use a harsh acid? or am I way off.
<Way off. You can't create acidic conditions without first removing carbonate hardness (alkalinity). In a nutshell, hard water resents any attempts at creating acidity. This is why hard water is so good for keeping fish: you get stable conditions. All practical attempts at creating acidic conditions have to go along with creating soft water; you create soft water with low (though rarely zero) carbonate hardness, and then add some type of acidic buffer that doesn't just lower the pH (for example to 6.5) but then also prevents further lowering of the pH.>
Again thank you for your responses you have been extremely helpful.
<Cheers, Neale.> 

Odd Water Parameters, FW... no Alk!  -- 09/03/09
Hey there WWM Crew- I have planted two tanks, one 10g other a 29g. Recently I discovered some very unhappy fish and tracked it down to a drop in my tap pH. All parameters (nitrates, nitrates) are appearing okay. Buffering capacity is 0! (NOT OKAY!)
pH is showing up as below 6.5 (that's as low as both types of my strips go!)
<Not good...>
I've been reading and am totally confused as *how to raise the buffering capacity and the pH on a regular basis and keep it stable*.
<Surprisingly easy. Do read here:
Typically, unless you're keeping fish that need hard water (e.g., livebearers, goldfish) simply use one-quarter to one-half the dose recommended for the Rift Valley cichlid salt mix will increase and stabilise pH for pennies a month.>
I tested two different water taps, and I was wondering (also) if it's normal for one tap to have a pH of 7, and another to have 6.5 or lower.
<Not normal, no. Do watch that some tap water, especially well water, has variable readings across a period of time after it is drawn from the tap.
Testing water, then leaving it for 24 hours, and then testing a second time, is often revelatory. Also, all aquaria tend to become acidic over time: accumulation of nitrate, decaying organic matter, tannins will all
lower the pH. Conversely, photosynthesis raises pH because it uses up dissolved CO2 during the day. Within reason, fish tolerate these changes reasonably well, but sudden changes can cause problems if there's ammonia in the system, because ammonia becomes more toxic as pH rises (if I recall correctly). So overall you want a steady pH.>
Shouldn't the entire house be using the same water source? I would like to use the tap with the pH 7, but cannot as the water siphon cannot connect to that faucet. Any help would be appreciated. City water reports state that water should be in the 7.2 range. I'm guessing this may be a plumbing issue- is that even possible?
<Use the Rift Valley salt mix suggested, at 25-50% the dose required. A pH between 7 to 7.5, hardness 10-15 degrees dH is ideal for most community fish.>
-- Thanks! Anitra
<Cheers, Neale.>

Red devil 05/27/09
Red Devil Acting Strange After Large Water Change
My red devil has been acting strange for 3 weeks now after a 100% water change. He hides and acts scared and rarely eats. When no one is in the room he darts across the tank charging the pump knocking it loose, the thermometer, (he has broken 2) charges head on into the tank. I have treated him for every external and internal disease I thought he might have. I took a water sample to the local pet shop and the said the pH level was low. I purchased the pH up, treated the water and had it tested again.  Now its fine, but his behavior has not changed. I've only had him 10 months and he's about 6 inches long. This is the first time he has been sick
< I don't think he is sick but I do think he is stressed from the 100% water change. There was probably a big change in water temperature and water chemistry. Try smaller but frequent water changes and try to provide some shelter for your red devil to hide until he feels comfortable to come out. Eventually he will associate you with food and stop hiding. Then you can get rid of the shelter.-Chuck>

Re: Red devil -Changing pH 05/27/09
There was also a white gelled mucus is the tank but I haven't seen any since I treated for the pH levels.
< When you play with the pH by adding chemicals you may get some minerals precipitating out of solution. Later they may get redissolved. I would recommend that you never change the pH of the water in the aquarium. Instead, us a 5 gallon bucket to change the pH and then use this water to slowly change the pH as you do your water changes. Swift water changes are no good for your fish.-Chuck>

New Gourami  05/23/09
New Gourami Adjusting To New Tank
Hi! I have read through your FAQ page and Google, and cant find the exact answer I'm looking for. Basically I just bought a new blue dwarf Gourami, and I have never had one before. I have brought the pH of tank down to 6.5 and it is set to 26 degrees Celsius. There is no nitrate, nitrite or ammonia in the tank. Basically the fish is swimming fine half the time, but then will stop and float randomly. or tilt to the side. is this normal behaviour? To me it looks strange/odd for a fish to do this if it is well...
Other fish in the tank:
2 platies, 2 guppies (its pretty quiet at the moment!)
I would really appreciate a reply, I love the look of these fish but I have only ever had livebearers and catfish previously!
Kind regards, Georgina
<The fish store probably had hard alkaline water. You Gourami probably is having some difficultly adjusting to the lowered pH. Much of the country has hard alkaline water. When you add new fish that are not adjusted to the new water then there may be problems. Try to keep the water consistent at the present levels for awhile and see if his behaviour improves.-Chuck>

Re: new Gourami -New Gourami Adjusting. pH Question  05/23/09
Thanks so much for the fast reply Chuck,  The Gourami is doing better!! no more floating anyway! I just have one more quick question - when I tried to lower the pH of the tank - it was jumping around too much for it to be healthy.... how would you suggest lowering the tank to 6.5 safely (it is currently at 7)? I have bought pH down, and also a container of proper pH 6.5. My tap water is around 7.5 so I cant really just keep it at that.
Kind regards, Georgina
< Adjusting the pH can be a very dangerous game to play. Your tap water is 7.5 and probably the tap water at the local fish store is probably 7.5 too.  If you change the pH of your aquarium then all the new fish may have
problems adjusting like your Gourami. Most fish will do OK at a pH of 7.5 once they are use to it but the soft water varieties probably won't breed.  Wild South American fish seem to have the most problems like cardinal tetras. If you do want to lower the pH there is an OK way and a very good way. The OK way is to take a 5 gallon bucket and fill it with your tap water. Add the pH down as per the directions on the package. Check it after 24 hours. Add more pH down if needed. Check every day until the pH you want is stable for 24 hours. Then use this water for water changes changing no more than 10% of the water at a time. Slowly over a few weeks the acidified water will be at the pH you desired. The best way is to take R/O water and add a buffer to set the pH where you want it. Follow the same procedure in a 5 gallon bucket. I would not recommend messing with the pH for the fish species you currently have.-Chuck>

Question RE previous advice given by Neale, H20 chem., FW    5/7/09
I wrote in a week (?) ago or so about water chemistry, and having a high level of sulphur in my well water. I am taking Neale's excellent advice and have decided to keep Mollies for starters once my tank is done cycling. My question now is regarding the salt mix. I'm going to maintain my SG level at 1.005 (hope I got that right), and looked at the salt mix recipe listed on your site (Epsom, baking soda, marine salt). I purchased some Instant Ocean marine salt mix to use, I'm hoping this is the right stuff. Here is the meat of my question: I read on your page about what different ingredients do to PH and hardness, since my water has a very high PH (about 8.4), and is very hard carbonate and bicarbonate, will the salt mix (or some of the individual ingredients that is) raise these even higher?
<The effect will be marginal; while marine salt mix contains some carbonate hardness, carbonate and bicarbonate are buffering in both directions:
besides stopping acidification, they also inhibit pH rises above a certain level too.>
Is there maybe an ingredient I should leave out? Or, since I gathered from reading, "tonic" salt won't do anything to PH would that be a better choice?
<Tonic salt isn't a better choice, though I dare say given your local water conditions, it would work adequately well. In any case, Mollies (and livebearers generally) are happiest in "liquid rock" so what you're doing here isn't going to cause them any hardship.>
Thanks again for you all of your help, and sorry I don't seem to grasp all the concepts easily!
Thanks again!
<Cheers, Neale.>

Lowering pH for Discus  9/25/06 Hello Guys, <Hi Eric, Pufferpunk here> Pls ignore the earlier email, have some typos. Thank you. <Thanks for the retype.> Need some help here: I have a 180G tank (with sump) and my PH was rather unstable. It kept on increasing and at one point, it was as high as 7.8-7.9. My tap water is hard pH 7.5. I only have ceramic rings and bio-balls (wet dry) for biological filtration (activated carbon too) and some wool for mechanical filtration in the sump. As far as I am aware, I do not have anything else that may cause the PH to go up. KH is 2.5 Ammonia is 0 Nitrite is < 0.3mg/l Nitrate parameter is <50. <Nitrites should always be 0, nitrates <20.> Anyway, was kind of worried about the high pH, so I went out and got myself a pH controller (+CO2 tank w/ solenoid valve). With that in place, I was able to drive down the PH to about 6.6 and maintain it at that range(+ - 0.1 PH swing). I think is rather all right for discus (correct me if I am wrong here). <Most of the discus available in the aquarium trade are tank-bread in tap water.  It's not necessary to adjust the pH lower than neutral.> When the pH controller activates the CO2 tank (via solenoid valve), it release the CO2 into the water and it is able to bring down PH by 0.1 to about 6.5 in 3minutes (through a DIY recirculated diffuser). It takes about 25minutes for the PH to shift back to 6.6 before the pH controller kicks in again. My question is whether the frequent PH swing is something I need to be worried off? <PH swing is more stressful then a higher, steady pH.  ~PP> PH Controller kicks in @ 6.6 Drives down PH to 6.5 in 3minutes Takes about 25 minutes for it to reach 6.6 And this cycle repeat itself again. <Seems unnecessary to me.  More large, frequent water changes with tap water (I do 80% weekly) should keep it steady.  ~PP> Thank you. Regards, Eric

Freshwater high pH    02/17/07 To The WWM: My tapwater has a pH of 9.1 Should I add some chloridic acid in order to achieve a better value for angel fish (freshwater) or could you suggest another method? <Another method... starting with "cleaner" water through RO, other filtration, using other products/acids, peat et al. filtration...> When adding top off water is necessary to adjust previously the pH using acid? <Best to adjust in some way ahead of time, yes> Could you suggest also the acid dose per litre? <...> The RO/DI water can do something about it? Or it just influence the water hardness? Thank you very much for your help Flávio <Please read here: http://www.wetwebmedia.com/FWSubWebIndex/fwph,alk.htm and the linked files above. Bob Fenner>

High pH We have a 38-gal. freshwater tank that has been set up for a month. We cycled with 5 zebra Danios (that seems like a lot now but it was in keeping with the first material I read) and just recently added 2 Corydoras catfish. In my preoccupation with ammonia and nitrites, which are both at zero now, I completely overlooked the pH, which is 8.8. <Yikes> At first I thought it was something in the tank or that it was because it hadn't finished cycling, but we tested the water from the tap and found it also is that high. It's well water, going through a softener... <Really? I wonder what sort of softener, what is elevating the pH like this?> ...with Kordon Novaqua Plus conditioner... <A good product> ...added as recommended by my LFS. I found your website a couple of days ago, and have learned a lot. Thank you for making this information available! I would appreciate your advice about this situation. Based on what I've read, I need to change the pH (although the current occupants seem active and happy for the moment). <You are fortunate in your choices... some groups of aquatic life would take exception here> Before I commit to adding anything to the tank or buying water, I want to make sure it's the right decision. The LFS has suggested that I buy RO water from our local grocery store and start phasing it in with each water change. <One solution, yes> If I do that, how quickly should I change it, and what do I need to do with the water before adding it to the tank?  <Gradually... like ten percent of the total volume every water change... weekly or so> I've seen a lot of discussion of purchasing RO units, but I'm a bit confused. Would that lower the pH sufficiently? <Yes> Would you recommend something else entirely? Thank you for your help. Julie <A few things to consider... One, maybe going with aquatic life that tolerates or enjoys high pH... Using biological mediation to lower it (live plants, time...), using inorganic acids (phosphorics mainly... commercially produced).... But if it were me, my home, water, I would look into reverse osmosis... for myself (drinking and cooking) as well as the aquarium/s.... Water of this high mineral content is actually not good for you... I would have it checked (if you haven't recently) through a water quality lab... We use RO for these purposes (though the African Cichlids get straight tap) and our pH is a paltry 8.2... Bob Fenner> 

High Ph in soft water!? Hello, <Hi there> Almost everything I have read concerning Ph and KH associate a high Ph with a corresponding high KH and visa-versa. <Yes, usually these two are linked as you state... but not always>   However I have a high Ph and a low KH.  Readings are vague because the test kits are so hard to read,
<Mmmm, there are better kits, methods> (different shades of color that change depending on how you hold it, light it, etc) but safe to say that the Ph is between 7.2 and 7.8 and the KH is between 3 and 4 dKH.  My general hardness is the hardest to test since the color change between red and green is hardly noticeable, but I think it is between 0 and 2 dGH.  The same results are obtained in both the tank and the tap with only a very small difference. I have been trying to prepare my tank for Discus and Severum and want to lower the ph to 7.  Peat is out of the question since I don't want tea colored water, so I have been using a Jungle brand product called Correct Ph 7.0.  My reason for choosing this stuff is because it claims to not only bring the Ph to 7.0, but it also holds (buffers) it there.  My results with this product though have been a rise in KH and no change at all in the Ph. <Now this is interesting. Might I ask, have you taken the opportunity to query your water supplier (should be listed on your water bill) re your water quality? Contacted Aquarium Pharmaceuticals re?> After a few days of using this, my Ph is the same and the KH is up to 7 dKH. I have no idea what is in this stuff since it has no ingredients on the label.   <I think, though am guessing that it's a mix of biphosphate (mono and disodium) and carbonates, bicarbonates... These last will raise the KH...> I put some specks in my test tubes, and there it initially brings the Ph down, but within a few minutes of agitating the Ph comes back up, and the results on KH are a seemingly permanent rise in KH.   <Mmm, yes, the shaking introduces a good deal of oxygen, drives out carbonic acid (CO2 in solution) will temporarily elevate pH... with resting you'd see it drop again> My question to you is how can I lower my Ph and keep it (buffer it) there? <Mmm, there are a few ways... am going to attempt to make this subject/monologue simple... You can/could start with "cleaner" source water (the cheapest, easiest to get, haul about: Reverse Osmosis... but deionized could do... you might go broke, but end up with big muscles hauling such prepared water about from other sources (outside your home)... You might just treat batches of your source water in a dedicated "trash can" (my fave the Rubbermaid "Brute" line... with cover, rolling cart...) with organic or inorganic (the last especially can be dangerous in concentration) acids, some understanding of alkalinity, testing...) You could utilize Discus (and even Severums) that are from generations that have been cultivated in captivity... and not worry (really) at all re your water chemistry... You could have another system with a good mass of live plant material that would condition new water, and move said water to your cichlid tank weekly and replenish it ala Boris Karloff...> I have spent days reading your site and it is fascinating.  I often get side tracked reading through the plethora of information, but nothing yet directly addresses my issue. <Will (gladly) admit to this disingenuous method of getting folks to read, consider "collateral" information, consider issues we deem important... If you have input re how to improve this process, please remit>   For all that I understand to this point, with water as soft as I have I shouldn't have a problem with high Ph at all.     <Ahh, my friend... this is so. You really don't... You will/would see in actual practice, using "just" the source water you describe, that likely you would have to add (bicarbonate likely) buffer to it, as with use/time your low buffering capacity will be exhausted and the pH slide downward... My real "advice" (what I would do) is to go forward with using the tap/source water, monitor pH, alkalinity, hardness... and adjust, along with good sized weekly water changes as time goes by. I wish you well. Bob Fenner> Thanks, Scott  

pH and gravel algae 10/25/05 I have a 55 gallon tank with 6 neon tetras, 3 platies, a Pleco, and a dwarf blue Gourami. My nitrates are around 20-30 with weekly water changes (about 10 gallons). No ammonia or nitrites. pH is currently 7.0. No natural light - fluorescent lighting 10hrs daily via a timer. During cycling as our nitrites went up gravel algae began to take over requiring a weekly scrubbing of the tank and decorations. I've read and read about gravel algae and I think I'm contributing to feeding my pest. Our water PH is 7.8 out of the tap. I use Proper PH 7.0 to lower and keep it at 7.0 (never had a problem with pH swing though as our water is loaded with buffers). But on the bottle it even says you can't have live plants with this product as it is a phosphate buffer. (I was hoping to add live plants to my tank eventually to help with my nitrates and gives my fishies some snack food.) Not to mention that this gravel algae is driving me insane... <Mmm, with the fishes you list, you would be better off giving up on pH modification through chemical means, and using live plants... for all sakes. I would leave off with the pH treatment, make weekly water changes with gravel vacuuming (gone over on WWM), and start with some hardy, floating plants... these will eliminate your algae problems, make the system far more viable for your fishes> I thought of a solution that might help - as I do my weekly water change if I add a slight bit less PH 7.0 every week until it gets to 7.8 (using no PH 7.0) <Ah, yes...> that would reduce my phosphate to quit feeding the algae as much. But would a PH that high be harmful to my current inhabitants? <You will find the pH doesn't "rise" to 7.8... but is moderated by influences in the system itself... just do the frequent partial water changes, add the plants... and you will see. Bob Fenner> 

High pH, alkalinity, and calcium Bob, We have a 20 gallon freshwater tank with cichlids. WE are trying to move them into a 46 gallon tank. The water in the new tank has been set up for almost 3 weeks and the ammonia and nitrite levels are fine. The problem lies with the pH, Alk, and Calcium. We cannot get the levels down. WE have tried water changes, proper pH, pH down, and water conditioner. We have been adding bacteria daily, and put trace elements, cichlid salt, and gravel from the old tank. The pet store said to get feeder fish to get the cycle going, they have been in there a week (only 4 have died) and no change in any levels. We have tested the tap water and the levels are not nearly as high as in the tank. What should we try next? We are becoming quite frustrated. Thanks, Jennifer <Many things to relate to you here... but do need to know more specifics... as you can appreciate I have no idea what sorts of cichlids you have (some enjoy very hard, alkaline, high pH water...), nor what your readings are for pH, Alk, and calcium... By and large however, I will tell you that systems tend toward acidity (they're reductive environments due to crowding, over-feeding in a small volume...) and so pH trends down... Your water may not be that unfavorable is what I'm trying to say... Get back to me with what your actual readings are, your type of cichlid fishes... Re the feeder use... not a good idea... very often these Comet Goldfish have parasite problems that they transfer to a new system... Next time, just some food sans fishes, or a bunch of live plants, used gravel, used filter media... Bob Fenner, www.WetWebMedia.com>

HELP! (concerns about high pH, use of muriatic (?) acid) hi This is Bonnie Vest I would like to ask you a question is it safe to put food grade neorotic <Muriatic> acid in my freshwater tank to lower the ph and possibly clear the tank up?? <Think your spelling is off... but no to using this likely inorganic acid... unless it is very dilute and you absolutely understand what you're doing (particularly the relationship of alkalinity/alkaline reserve and pH, and have test kits for the former... very easy to get into trouble here. Unless you have livestock that requires a water of a pH outside this range, I would just wait, and your pH will drop in time.> My tank is very cloudy and the ph stays @ 7.4 & higher I need help Please!! <Take a read through the materials on "pH, alkalinity" on the freshwater part of our site (WetWebMedia.com) and read through the associated FAQs file... locate a bit of live plant as proscribed there, and relax... If set-up properly, your system will clear on its own soon enough. Bob Fenner> Thanks again Bonnie M. vest

Re: HELP! (concerns about high pH, use of muriatic (?) acid) we have had our tank since January and the ph has stayed high and the tank cloudy are you sure there is nothing we can do to keep at least the cloudiness down?? <Hmm, all sorts... what sort of system is this? What filtration, substrate? Livestock? What do you feed? Is your tapwater cloudy right out of the source? What if anything do you treat it with before using? What is your maintenance routine? There are definite reasons for your system to be "out of balance" and easy ways for you to correct it. I will help you. Bob Fenner>

Freshwater aquarium water hardness question! Hey guys, I was wondering if someone could give me a couple ticks and help me with this dilemma? My modest 20 gallon aquarium is about six weeks cycled and most all levels are in the 'kosher zone' ammonia at or around 0 ppm and nitrite about the same. Now to the crux of the problem, my ph is at 7.3 - 7.6 and my KH is at 2 dKH and my general hardness is only registering a reading of 1 dKH!  <wow! Very soft... you should breed Discus, Angels or killifish...Ha!> I'm using municipal water which I treat with ammo lock2 before water changes. I'm using the liquid reagent type kit from aquarium pharmaceuticals. The only store in my area sadly enough is Petco and seems most are under educated in regards to true water chemistry (wow imagine that, right!?!) So I have a sample tested and I get a line from the clerk that goes to the tune of, everything is looking good, ammonia, cl2, nitrite and so on... then she say's I have a very high ph and to do another huge water change maybe as much as 90% and it won't bother my tetra. I have one of two tetras left, however the day before I had done a 25% change, anyway so I buy the master freshwater test kit I spoke of earlier and do all of my tests and registered results noted above, my tap water when tested twice on different days read when tested: ph 7.0 - 7.2, GH 1 dKH, KH 2 dKH, is my test right if so what should I do to increase the GH for a rounded community tank?  <if you like tetras and South American fishes as a rule, you won't need to bother too much with it. It will be a blessing to have such soft water. If however you get rid of the tetras and add livebearers, goldfish or African cichlids (not all together...<G>!), then you will definitely want to add a buffering product like those used for marine aquaria. In the meantime... some carbonate material like a bag or crushed coral in the filter or some sea shells/coral in the tank will help a bit. Do keep up with regular water changes too... very important> I probably won't ask for advice from the mega-pet-mart's anymore either -the girl at Petco didn't know what effect the KH & GH had on the tank! (I'm nearly positive all they know is how to test samples and then tell folks to do huge water changes at any type of anomaly, I suppose that's fine if it corrects the problem,  <yes... as a rule, when in doubt: do a water change> but not always as I'm having issues with my water source. I had to research to find out about buffering for ph and the likes. Thanks in advance. another happy fish person, Lonnie <cheers! Anthony>

Raising the pH Naturally I currently have water that my Mbuna cichlids absolutely love. As a matter of fact I pull it straight out of the tap and do nothing else. It's well water don't ya know. Anyhow, I am moving to city water that is 7.1 as opposed to the 8.2 I enjoy now. Is there a way to raise the ph of the water up to around 8.2 naturally. By that I mean without adding buffer or something to that effect. I understand that between Aragonite Sand and crushed Coral as a substrate I might get it up to around 7.5, but how do I get it up around .6-.8 more? By the way it is a 125 gallon tank.  If it matters I have the following fish. Labidochromis Caeruleus-3 Ps. johanni-2 Ps. demasoni-2 Ps. flavus-2 Ps. polit-2 Ps sp. Msobo-2 Ps. zebra-OB marmalade-5 (I think it is the right species) Maylandia Greshakei-2 Thanks for any help or advice. Charles <The easiest, safest way is going to be with a buffering compound. I like Seachem's buffer and salt for African cichlids. -Steven Pro>

- Freshwater pH - <Greetings, JasonC here...> Another question for ya guys I have a 55 Gal freshwater tank Ph 7.0 Nitrates are off the chart. Am doing water changes to lower the nitrates. The tap water Ph is 7.8 every time I make water changes the Ph in the tank goes up what is the best way to control a steady Ph rate of the 7.0 in the tank during water changes? <You might try the product, pH Down, which is a weak/mild acid that is safe to use in aquaria. Do add to the change water sparingly and test before adding to your tank.> Also I have a fine film floating on the top of the water what is it and how do I get rid of it? <Not really all that uncommon, you might try finding a surface skimmer for that Emperor filter.> I am running a undergravel with 2 power heads and an Emperor 400 with Bio wheels and carbon. Thanks again as always and Merry Christmas Bill <Cheers, J -- >

Malaysian Driftwood, pH Reduction Hello. <Scott F at your service> Where I live the pH is high; therefore, the pH in my 10 gal tank is also high. <Just how "high is "high"? It may be acceptable, depending upon the kinds of fish that you keep> Someone suggested that I purchase some driftwood since it would help lower the pH in my tank, but I should let it soak since the wood would tint my water until the water becomes clear. Is there any way to speed up the process of getting rid of the brownish water?  <Activated carbon in your filter should do the trick. Using driftwood, peat moss, etc. to lower pH may be hard to control-much depends on the rate of dissolution of the tannic acids, etc. present in the wood. If you are dead set on lowering the pH, you may want to use one of the prepared products designed just for this purpose > Are there any other "natural" ways to lower the pH in a high pH area?  <Do read this faq: "pH, Alkalinity, and You" in the freshwater articles section of wetwebmedia.com> Thanks, Rachel <And thank you for stopping by!>

Low dKH Hello Ladies and Gents of the Crew, <<Hello, hello'¦>> I've recently set up a 29g freshwater tank - 10 days ago.  Water is cycling nicely.  In the tank I have 40lbs of gravel, several rocky caves, one piece of bogwood, Proquatics power filter at 200gph, an Airtech pump with bubble wand type thing, and a submersible heater.  Temp has remained steady at 77F.  There are five plants: 1 green Cabomba 1 green Lloydiella 1 red Ludwigia 1 Rotala indica 1 marble sword I add 1 tbls Kent freshwater plant supplement per week.  Will the plant supplement be necessary after I have fish established in the tank? <<Possibly. It certainly won't hurt to keep using it as long as it says it's safe for fish (I would certainly assume it is!) but you can try going without it and see if your plants start failing. I don't think they will, I have several of these same plants in a tetra tank and they are all doing fine with no supplements.>> I ran tests last night (AquaPharm liquid) Ammonia - 0 Nitrite - 3 Nitrate - 5 pH - 7.1 GH - 3 dGH  (53.7ppm) KH - 2 dKH  (35.8ppm) I tested the tap water and the pH, GH, and KH are all the same as the tank water. Okay, my real question is this:  Is this very acid water going to create a problem with the pH stability? <<The low dKH could cause problems with Ph stability. Since your tank currently has no fish, this is the perfect time to raise the DKH. There are commercial products that will help with this.>> And what kinds of fish will thrive in this environment?  I know Discus like the softness, but the pH is still 7.1 and besides that the tank is way too small.  Will the hardness rise as the tank completes its cycle?  Any suggestions on fish?  Is it too soft for Corydoras catfish?  (Just love those little guys.) << There are many fish that will do fine in these conditions and it's fine for Corys. There is quite a range for what Corys can handle, pH range: 6.0 - 8.0; dH range: 2.0 - 25.0. >> One more thing, I am in the planning stages of my first saltwater tank.  It's either going to be 90g or 125g.  But, since testing this water, I am greatly concerned about its buffering capacity.  I want a FOWLR with a DSB.  Have been reading your website for about 3 weeks now.  So much info to process!  It's wonderful :o)  Thank you for your time.  It's greatly appreciated. <<I'm by no means an expert on saltwater but I believe if you use a substrate specifically for saltwater tanks these will help greatly with your buffering capabilities. Crushed coral should do nicely.>> Jen

Increasing buffering capacity in FW tanks Dear Crew, I have 5-gal. and 10-gal. freshwater tanks that are well-established.  Municipal tap water (ozonized, not chlorinated) is pH 6.2, GH 6 degrees, KH 6 degrees, zero nitrates. I have platys, Cory cats and algae eaters in both tanks. Both tanks test pH 6.0, ammonia 0, nitrite 0, GH 6, KH 6.  I just bought a nitrate test kit and was shocked to find out both tanks are off the chart!  I do 20-30% water changes weekly but both tanks are somewhat overstocked (those oversexed platys keep having babies) and I do tend to overfeed a bit.  After using Aquamarine Nitrate Reducer (a bacterial product) an algae bloom cleared up completely so I thought I had solved the nitrate problem.  I plan to get Coralife Nitrate Remover and I will do more water changes, so I am not so concerned about the nitrate. <I would be. If you are concerned with buffering, this is to counteract acidic wastes, IE: nitrates. Overfeeding, fouled substrate, filter media, filter sponges, bio-wheels and bio-balls all produce nitrates from nitrites. It is best to reduce these sources of nitrate pollution.> My question is about pH and buffering capacity.  I am of the school of thought that you should not adjust pH, simply require that your fish get used to whatever your tap water is. <This is a complete fallacy and is inhumane to your fish. Fish don't just adapt to improper pH, alkalinity and salinity that took perhaps millions of years to evolve to. That's why we don't see marine fish in the Amazon or sharks in your toilet. You are blessed with soft, acidic water.  This means you can either choose fish from soft acidic conditions (Discus lovers would die for your water) OR you can add buffer to add alkalinity/hardness and raise your pH. You only need to raise your pH to 7 and hardness a hair for all your fish. The nitrate is a bigger concern.>   However, since my water is so soft, I am afraid it doesn't have much buffering capacity, and am worried that it will get too acid if I should be late with a water change.  Do I understand correctly from previous posts, that adding baking soda increases the buffering capacity (alkaline reserve)?  Or does it simply make the water more alkaline?  Also, live plants use up the carbonate and reduce the alkaline reserve?  Both tanks have flourishing Java Ferns and Water Sprite, which grows so fast that I have to weed out great handfuls of it. <Again, this is nitrate, the key ingredient to most fertilizers. That your plants are growing profusely in acidic, soft water is an indication that these nutrients aren't that necessary as opposed to the nitrate levels.> I had thought to get Kent pH Stable. Would that be appropriate?  I have some Seachem Equilibrium because I thought the fish or plants might like the water a bit harder.  Would that increase the buffering capacity? <If these are FW buffers, only enough to raise the pH one point.> I thought about Seachem Neutral Regulator or Kent pH Precise Neutral Regulator, but both soften the water!  Do they precipitate out the calcium and magnesium?  Shouldn't I be making my water harder, if anything? <Just a simple buffer and waste reduction/prevention. Get the numbers down, stop overfeeding, OR get up to speed on maintenance for the load you have.> Another question that NO one in the LFS has been able to answer -- I add 1/2 tsp. salt per gallon to make the platys happy (and they do indeed do better with the salt).  Is this enough salt to prohibit using "freshwater only" water treatments such as Nitra-Zorb, which is regenerated by salt? <It may leach *some* by ion exchange with sodium ions, but not like the saline solution required for complete regeneration.> I do not have a phosphate test kit.  Do I need to be concerned about the phosphate level, if I don't have an algae problem?  Does it hurt the fish?  Thank you for your assistance. Your web site has been invaluable. Sincerely, Marron <An adequate program to reduce nitrates should also reduce any phosphates. If you are trying to stretch your maintenance schedule or are having nutrient problems, then test kits are vital. Better get after those water changes and gravel vacuuming!  Craig>

Re: acidifiers Hi, I just had a quick question.   I have used citric acid for farm uses to reduce the PH of drinking water for swine.  I was wondering if this could also be used to lower the PH of my aquarium water?  I am thinking if it is safe for animals to drink, then maybe it is safe for fish to swim and breathe in? <Yes, this is a not-uncommon additive to some marine fish medications, particularly copper compounds, that otherwise "fall out of solution" due to the alkaline nature of seawater. Bob Fenner> Thanks, Jess

Re: acidifiers Do you have any idea of a measurement to use to lower for instance 1 point. I only have a freshwater aquarium. Thanks for the quick response!! <This is reliant on the alkalinity of your existing water. How to put this... water is more than just H2O... it has buffering capacity, mainly carbonates, bicarbonates that "resist" pH change... and all waters are different in this capacity (alkalinity). You can get/use an alkalinity test kit... or just try adding some citric to a given volume (outside the tank) and recording how much it shifts pH. Please see here re: http://www.wetwebmedia.com/FWSubWebIndex/fwph,alk.htm Bob Fenner>

Re: acidifiers sooooo if i am going to have a freshwater tank and currently our water measures about 8.5, would you use citric acid to get it down to that 7 range?? thanks again <If that is the range your livestock enjoys, sure. Most commercial "pH adjusting solutions" are phosphoric acid... a few are dilute sulfuric... Citric is safer, to use than these, but can't be as easily stored in aqueous products (microbes start growing in it over time). Take a look on the Net re Citric Acid... it's very commonly used, relatively safe. Bob Fenner>

High pH question Hello WWM Crew... <Hello, Gage here avoiding real work as best I can.> I'm setting up a 75-gallon FW community tank and I have a concern about pH. My tap water is 8.2 and I have done nothing to adjust it. I have read here and elsewhere that it is better to have the pH too high than to play with it and risk sudden changes. <I agree> On the other hand, I have heard of a great number of people who adjust their pH to exactly where they would like it to be. <can work as well, its up to you.> I have three Buenos Aires Tetras and three quite small Bala "Sharks" now and intend to ad Rainbow Shark, Clown Loach, Pleco or maybe Pictus Cat. Am I doing the right thing by leaving the pH alone? Thanks. --Charlie <My tap water has a rather high PH as well.  I do not adjust it and get along ok.  If you would like to adjust it get a separate container dedicated to mixing water, the large 44gal Brute garbage cans work well.  Mix your water and adjust the PH in there before adding it to the tank.  If you do decide to adjust the PH, bring the PH down in your main tank slowly.  There is a HUGE difference between the ph measurements.  We have got some good articles on the subject.  If you have not checked them out already I strongly recommend it. -Gage http://wetwebmedia.com/FWSubWebIndex/fwph,alk.htm  >

pH is dropping! I have an 80 gallon tank with African cichlids and have lava rock as hiding places for them.  I measured the ph in the tank and was really surprised to find out that the ph was 6.3 instead of 7.5 to 8.2 and was wondering if the lava rock will lower the ph that much.   <Generally a pH drop like that happens when the water hasn't been changed in a while. The longer a tank runs without water changes, the lower the pH will get. Lava rock shouldn't drop it like that.> I plan on adding Seachem Malawi Victoria buffer to raise the ph but was concerned about ph shock.  The Malawi Africans that are in there are healthy along with some babies and I was also wondering if I should let things go or go ahead and add the above buffer. <Rather than adding a chemical at this point, see if you can gradually bring it up with water changes. Chemical fixes are only going to be short term solutions. But whichever way you go, the pH should be brought up gradually, not all at once. Ronni>

Clown Loaches & German Blue Rams... I've really enjoyed your website and have a question for you regarding water parameters for my Freshwater Aquarium.   <Thank you, I'll do my best to answer> I live in Northern New Jersey where we have relatively hard water and Im trying to keep my German Blue Rams and my Clown Loaches comfortable.  I have read that both the Clown Loaches and the Rams prefer softer water.  I have a 55 gallon tank with 3 German Blue Rams, 8 Clown Loaches (four 6" loaches, two 3" loaches, two 1 to 1-1/2" loaches). In addition I have two 5" - 6" Pink Tailed Chalceus, four 4" Iridescent Sharks, three 2" tri-color sharks, one small Pleco, and 3 small Cory cats.  I am planning on upgrading to a larger tank in about 6 months knowing that my sharks are probably going to outgrow this one. <Yes, you'll definitely need a larger tank very soon. Your Clown loaches could reach sizes of 12' each and the Pleco can get around 20'.> My Tank: PH - 7.6 Ammonia - 0 Nitrites - 0 GH - 9 KH - 4 I have recently put some of Fluvals Peat Granules into my Fluval 304, hoping to soften the water and lower the PH levels.  I have been doing small (10%) water changes weekly.  And I have provided ample hiding places for the Clown Loaches (there is a house/cave on either side of the tank for them to hide in, as well as plants and rocks for additional cover).  So my question is what can I do in addition to the Peat Granules in my filter, in order to give my Loaches and Rams better water quality (Softer - Lower PH).  I am currently just using tap water with conditioner to do my water changes and would like to provide the ideal environment for my fishies. < The peat should help and really there's not a lot else you can do that isn't going to cause fluctuations. The best thing to do is provide a stable environment. They'll be much better off in a stable but slightly hard condition than in a fluctuating softer one.> Any suggestions or information you can offer would be much appreciated!!! Thanks, Stephanie Ward <You're welcome! Ronni>

Water too basic     I'm having some trouble with my water ph levels.  I'm a new aquarium owner of a 20 gallon tank and about a week ago I tried to increase the buffering capacity of the water by adding some alkalinity buffer drops.  But then the ph sky-rocketed off the charts when I tested it and hasn't gone down since.  Even when I made a 60% water change the other day! What can I do to lower the ph (I have 4 red eye tetras currently) without having it just bounce right back up? <Exactly how high is it? If it's high but still under about 8, your fish will adapt and do fine in this, just make sure to fully acclimate new arrivals. If it's over that, you'll need to isolate that cause of why it's staying so high. Generally when pH goes up it will also come back down, especially if it was raised with chemicals. To get it back down now you can do water changes with reverse osmosis water (many LFS offer this for sale), you can slowly but consistently bring it down with products like pH Down, or you might be able to do it with baking soda. Baking soda will generally raise your pH but a little experiment a friend and I tried found that it will only raise it to a certain point and then it will begin lowering it. I would try the RO water before anything else but definitely make sure there's nothing in the tank causing it to stay high and also check the pH of your tap water. Ronni>

Safe lowering of pH I'm sending this email for my dad. We're not sure if you can answer this, but we thought we'd try anyway. <We'll certainly try to help.> He would like to add rams to his tank which already includes discus, cardinal tetras, angelfish, and Neons. <Tank size?  How many of each fish, currently?  Please do be aware that cardinal and neon tetras will be midnight snacks for the angelfish (perhaps the discus, too), eventually.> The PH of the tap water is 7.4  He has been unable to keep rams. <Woah.  I'm surprised the cardinals and Neons are alive.  They almost require low pH.> Do u have any suggestions to lower the PH? <Using peat moss in your filter and adding bogwood to the tank will help.  The pH out of my tap is a whopping 9.2, but after filtering with peat, it comes down to 7.0-ish.  I imagine, starting with a pH of 7.4, you can get yours lower.  However, this will stain the water kind of a tea-like brown.  Personally, I find this extremely natural and gorgeously attractive, but some people dislike the coloring tremendously.  Another alternative would be to use reverse osmosis/deionized water (RO/DI), which is a pretty involved topic.  Begin reading on RO/DI here: http://www.wetwebmedia.com/rofaqs.htm and also the other RO/DI FAQs.> Adding PH drops hasn't helped at all. <Not surprising.  Chemical means of altering pH is not very effective, often short-termed, and will result in a pH roller coaster that may ultimately end up killing the fish.  Try peat and bogwood - and to keep things stable for water changes, use a Rubbermaid container/trash can for making water change water ahead of time, so you can soak some bogwood or peat in it to get the pH to that of the aquarium, so as not to shock the fish.  Peat moss that can be purchased at landscaping/gardening stores is okay, as long as there are *no* fungicides, pesticides, etc. added to it.  I believe the brand I use is "Sunshine".  -Sabrina>

Freshwater Sting Rays pH changing... To change my Ph level is it ok to use Muriatic Acid in my aquarium with Female Sting Rays which might be pregnant Thanks, John <I caution against (I would not do this) using Muriatic (aka non-stock molarity hydrochloric) acid. Use sodium biphosphate (the most common pH reducer sold as such in the aquarium interest), or peat, or other means. Bob Fenner>

- Carbonate Hardness is Too... Well... Hard - Hi Guys, <Greetings.> I have had my new tank (250L) up and running for about a month now. I put two of my existing bristle nosed catfish in the tank to cycle it. I know that these catfish are very sensitive to ammonia so I have monitored it closely. I added a bacteria solution (called CYCLE) as well to kick start the process. Doing this has worked very well. I have never been able to detect any ammonia but I am now seeing nitrates. <Sounds like your cycle has come full circle.> But on to my problem; I like my plants. I understand that they need a certain level of carbonate hardness. My tap water has low carbonate hardness (1-3 dH varying) and I have tried to raise it. I thought 5-6 dH would be OK. I bought some "KH up" powder from my local fish store (who are usually excellent) but all it seemed to do was raise my pH (from 6.5 to 8!). I asked them about this and they said that some pH rise was expected but that by adding acid this would go down and all would be fine. So I tried adding acid, I had to add a very large amount (around 100g which is 10 times what I would normally have to use). At this point I was concerned (the catfish would have had a hard time with the pH swing) but thought this would be OK. The pH was back were I wanted it and nothing had died. I checked the carbonate hardness again and to my horror it was 0. From this I had two thoughts: 1- The "KH up" powder was not "KH up" powder (but proved to be a very good way to raise pH and buffer the water) or 2- That some how the addition of the acid "removed" the carbonate hardness. <Bad move on the acid addition, or perhaps better said, shame on the fish store that recommended it. Essentially, the acid consumed the few buffers you had, and that was that... dH of zero.> I haven't tried to raise my KH since this rude shock but I want to keep my plants going strong. Can I have a low pH (6-6.5) and 5-6 dKH? <I think so, but likely not much higher.> If so how? <Well, first off you really shouldn't be making such drastic changes in pH - although your catfish have made it this far, I'd be willing to bet they're under tremendous stress. I'd just add baking soda - sodium bicarbonate - to the water you do water changes with, and change about 5% of your water each week. Give the tank some time, it is rather new, and I think things will stabilize.> Is my situation unusual? <Not really.> What chemical should I add to increase carbonate hardness? Are there any products available that raise KH and not pH? <Not that I am aware of.> Any help would be appreciated. Cheers, Adam, Australia <Cheers, J -- >

- Softened Source Water, Follow-up Again - A marine buffer in a fresh water tank?
<I'm sorry, my bad - just stick with the baking soda, it's really the primary ingredient in just about any commercial buffer product, fresh water or marine. Cheers, J -- >

Can't Keep it Up!  >I read the FAQs, but still have a question.  >>Ok, SHOOT!  >My pH is around 6.0 to 6.2, comes out of tap at 7.6, no ammonia or nitrites, temp 78. 40 Gal. tall, undergravel filter, power head, lots of bubbles...  >>"Lots of bubbles"? From what? If from the powerhead, then I'm wondering if you're using the venturi (which means superfine bubble-action), which isn't very good for your fish. The bubbles can get caught in the gills and cause something similar to the bends. Just an FYI, and a "heads up".  >...planted, do have 2 pieces of driftwood. My existing fish seem happy. Just can not seem to keep pH up.  >>Ok, if they're happy, why do you want to change it? Especially if you've got a planted tank, the plants will be less tolerant in their acceptable pH range than most of the freshwater fish we have available to us today.  >Don't like to add chemicals for this. LFS said it is because I live in Atlanta, GA, and it is hard to keep pH up with undergravel filter in this area.  >><giggle> Oh yeah? So, what they're saying is that if you used, oh say.. a BioWheel it wouldn't be so low? I'd be looking at the driftwood first, the alkalinity of the water second (or maybe first).  >We do 25%-30% changes every 3-4 weeks, vacuuming gravel. I do not overfeed. I have 1 Angel, 3 tetras, 2 Siamese algae eaters, 2 boesemanni rainbows, 2 turquoise rainbows, 2 Otocinclus catfish, 1 clown loach (I know he needs a friend, his partner died)  >>No he doesn't, he'll be fine. You do need to watch that fish load, though, which can be another contributor the dropping pH.  >1 dwarf Gourami. Could the problem be the undergravel filter?  >>No, not the filter itself. The substrate might be taken into consideration, but if it's actual aquarium gravel then it's highly unlikely.  >Or should I do the aeration test, have taken samples to LFS... did not say anything out of ordinary... just low pH... but I have tested theirs and it's about the same.  >>Alright, so, if their water is from the same municipality then I think we can safely assume that this water has very low alkalinity--in terms of "buffering" ability, as opposed to alkaline in terms of pH--this means that the water cannot hold the pH stable very well. It is VERY easily fixed, Monica.  >Also have a 10 Gal. quarantine tank with 2 guppies... also with undergravel filter... pH is low there as well.  >>We have terrific consistency here, all pointing to the same thing. I don't think I'd even spend the money to test for what's pretty much in our face.  >I have checked hardness before but can't remember what it was.... didn't really understand all of that... but reading the FAQ's enlightened me some.... thanks. Thanks in advance for any help. Monica  >>Alright Monica, your solution here is VERY simple, all you need are two things, a length of old pantyhose (no holes, please) and some crushed coral or dolomite. Just make a "snake" of the crushed coral with the pantyhose, and bury it in the gravel. That's it. It will take a while, but after about a month or so the crushed coral will help to bring the pH up as well as buffer the water. Do watch your plants during this time, they may not respond well to this. If you don't feel comfortable with this method, then consider looking into some of the many fine freshwater buffering products, especially those offered by SeaChem (an excellent company that offers very good quality products). This may ultimately be a better route to take to avoid bringing your pH up too high (in the >8 range), which is far more detrimental to your fish and plants. A quick Google search has netted me products from both Kent and Seachem that will achieve this at very reasonable prices. They may seem to be "chemicals", but are usually in actuality mineral in content. Marina

Buffering Fresh, 2.1 >Marina, Thanks for the advice. >>Quite welcome. >!ST bubbles from the bubble stones, not the powerhead. >>Gotcha, so you've got excellent oxygen/carbon dioxide (O2/CO2) exchange. >I did check KH and GH.... both WAY TOO LOW...... so I guess the best thing to do is to find some of the Seachem products. I do like Seachem best, as I said.  The products were quite easy to find online, and relatively inexpensive. >I have read that clown loaches do much better as a pair or more? Is that not so? >>They may be a bit happier, but honestly I've never known them to do poorly if kept singly, either.  They can grow quite large, though, something to consider. >Thanks for all the help. Monica >>Again, very welcome, I'm glad I was able to answer your questions.  Marina

Strange pH situation  >Hi,  >>Hi Caryn.  >First, I want to say "Thank You" in advance for offering the public such a service as this. Now I have a question that no one can seem to answer. My mother in law has a 26 gallon bow front tank that we got her for Christmas. I set it up (she knows nothing about fish but enjoys them) . We have goldfish in it. They have been doing great until the other day. There were 4 and 2 of them died. I tested the ammonia and the pH. I had a feeling it was the pH and it was.  >>So, you're saying that you've been monitoring pH, and saw that there was a big swing in a short amount of time?  >It was around 6.0 : ( very bad. I tested it out of the faucet and it was about 7.0 (still low). So my question is : What makes the pH go down???  >>Well, I'm not so sure that the pH necessarily dropped quickly, which is what would kill the fish very quickly. As for what can make it drop, lack of maintenance, excess food, certain types of decorations, all combined with water that has poor buffering ability (called alkalinity) can factor in.  >I can't figure for the life of me what would make it go down even lower than it went in.  >>See above.  >I did a 5gal water change and put a large sea shell in the tank and it's not come up at all.  >>A single shell probably won't do it, you'll need to add more than that, some crushed coral in a piece of pantyhose or similar calcareous substance.  >I am going to get some pH UP and use it. I don't like chemicals but have no choice at this time. I don't know what else to do.  >>I would strongly recommend against this, as it's going to be too easy to kill the remaining fish. I think that another factor here is that the fish in question may have simply reached a critical mass/density for the given water volume and filtration. I have none of this information, but can tell you that goldfish are very dirty as far as fish go. If the pH has dropped suddenly, then several large water changes is more in order, and only vacuum small sections of the gravel at a time (wait at least a week in between). If they're being overfed you'll see the results in the substrate, so that may need curtailing as well.  >I know it has to come up slowly. I just don't understand. Does anyone there have ANY ideas ??? Thanks so much for your time, Caryn  >>As above is what I would do, and don't add any more fish. Depending on the breed of fish, they may need larger quarters sooner rather than later as well. Marina

How to lower dKH Hi. My dKH is 17 how can i lower it. I made water change, but it go up. Tks. < Check your tap water first. Some areas of the country have high levels to start with. Check your substrate. Some things like shells and crushed coral sand will kick it back up. Check your rocks and decorations. Sedimentary rocks have been cemented together and may leech carbonates into the water. If your tap water is too high then you will need to remove these carbonates with a reverse osmosis filter or a deionization unit.-Chuck>

Buffering pH I'm nearly finished with fishless-cycling of my 55gallon tank.  My tank is currently consuming 2 or 3 ppm of grocery store ammonia in under 5 hours, my nitrite is 5~10 ppm and my nitrate climbing steadily. <Mmm, I'd cease with the exogenous ammonia use... maybe put a little dried food in this system... it IS cycling, will "cycle down" to useful bacteria "levels" (population, species dynamics, physiological activity> But, I'm concerned about putting fish in.  My tapwater comes out at about pH 8.0, but is insanely soft (KH 0.5~1.5 degrees).  As I'm cycling my tank, I'm consuming about 2 degrees of KH a day (whether from acid production or from my bacterial colony eating it, I know not). <Good guess, likely so>   I add about 2 teaspoons of baking soda a day, which bumps the KH up to 2.5~3.0, but forces my pH to hover above 8.0.  When the KH is consumed to below about 1.0, the pH drops to 6.0~6.5. <... Yikes! Time to utilize something else... Kalkwasser, or "Kalk plus" (sodium carbonate mainly)... as such or a commercial product/blend... Wait a minute! Is this intended to be a marine system?> This is obviously not an acceptable situation once I have fish.  What are good buffering products that will keep my pH reasonably steady?  I bought some Seachem "pH 7.0" product and added it to a bucket of de-chloraminated tapwater, but after two hours of aeration, it continued reading 8.0, not 7.0.  Can you make some suggestions before I give some innocent fish pH whiplash? Thanks! Chad <... Need to know whether this will be a freshwater or marine set-up... and if the former, what group/s, types of organisms you are planning on keeping. If it is FW, do consider starting with modified/filtered source water... the cheapest, easiest route here is reverse osmosis... and it DOES sound like you should use this technology for your own drinking and cooking uses as well. IF this is a marine tank, I would not be concerned re the eight or so pH reading... and go ahead with the materials mentioned above. Bob Fenner>
Re: Buffering pH
I'm planning for freshwater.  Probably a typical community tank: Angels, Corys, Danios, something like that.  So you like the "Kalk" buffers?  I'll look into that.  Thanks for the help! <Ah! Actually don't look into Kalk... but into practical (inexpensive, non-burdensome) means of starting with better water to begin with. Take a look here: http://www.wetwebmedia.com/rofaqs.htm and the other FAQs (linked, in blue, above) re tap filtration. Bob Fenner>

Lowering PH in water Gentlemen: I would like to inquire of you if you have ever heard of a product called Basic H. I read on an Angelfish web site to use Basic H for lowering your PH in your aquarium water. The only thing I can find on the web in reference to this is something sold through Amway. I would like to know if you are familiar with this product and it indeed is the product sold through Amway. < I did a Google search on basic-h and could find no list of ingredients so I can't really comment on how or why it works to lower pH. I will assume that it has some sort of phosphoric acid in it. If this is true then you could do the same thing with Muriatic or phosphoric acid from a pool supply place. If you really want to lower the pH with chemicals and additives then put your water in a 5 gallon bucket and then add the chemical of choice. Read the ph every day until it is stable. Then adjust the amount of chemical needed to bring the pH down to where you want it and keep it there. Never add any chemicals to your tank directly. Radical changes in pH can be and are often deadly to fish. Many fish can handle hard water but their eggs have a difficult time surviving.-Chuck> Thank you; Keith

Big Pleco in a New Tank Hello there. My name is Dayna and I have recently found your very helpful website. <Thank you> I was wondering if you could answer a few questions that I have? <Fire away> My husband and I recently (3 weeks ago to be exact) set up a 55 gallon freshwater aquarium. We only have a large 11" Pleco and no other fish. <That's a big Pleco to add to an uncycled tank> We are having a little problem with the ph. We bought Sodium Biphosphate recommended by our local fish store. It seems to work that day, but then the next couple of days the ph goes back to 7.6. <7.6 is not out of line unless you plan on keeping fish that require a more acidic level> Do you have to add this stuff daily? Is it toxic to the fish? Or could the ph problem be because the tank hasn't completely gone through it's "cycle"? <I would not add it at all unless the plan is for Discus or Rams. It is far, far better to get fish whose needs match, or can adapt to, your local water conditions. Once you change your pH you are committed to matching it with every water change. Should the need to do a very large water change arise, being off just a few tenths could cause pH shock. It's the swing in pH that kills, not an "incorrect", but steady, level> Also, the Pleco seems to defecate quite a lot. <Welcome to my world, normal for these large waste producers> I know that's what we all got to do, but could we be feeding him too much? We feed him one disc of the algae food. <No, that's not a lot at all for an 11" Pleco. Too little, if anything. Try giving him some fresh vegetables. A piece of zucchini, squash, carrot etc.. Also offer a small raw shrimp a few times a month. Attach to a rock and add at night. Remove leftovers in the AM. But wait until the tank is cycled to start target feeding him> The bottom of the tank and the plants have quite a bit of feces (looks very unattractive) even though we vacuum. But, when we vacuum it also takes a lot of the water out and I was wondering if it's okay to be taking out that much water that frequently? <Yes, in fact great! Small frequent water changes have many advantages in the long run. However it will slow down the establishment of your cycle. Keep them up so your Pleco does not have to go through a major ammonia or nitrite spike. Having the ability to easily do these frequent water changes is another reason not to mess with pH.> One more question. Do you recommend air stones and how many? The local fish store says that since we have the bio-wheel filtration <What size filter?> and under gravel filtration, with power heads, that we don't need any. <I would remove the UGF. They can have vast amounts of waste build up under them. If this decays in a "dead" spot (no O2) a deadly gas can be released into the water. They are also very hard to clean without tearing everything up and releasing the junk into the water. Your bio wheel, if it is the correct size, will provide far superior bio filtration than the UGF. The gravel vac will remove, not hide the waste. As to adding airstones, no problem either way. If you have the proper size filter they are not really needed, but can not hurt. I use two Emperor 400 filters on my 55 gallon Pleco tank and no airstones. My six Plecos do fine> Yet I have read that it's recommended to have 5 air stones for a 55 gallon. <That seems a bit excessive, but wouldn't cause a problem> Please help! We really want to get some pretty fish soon but are too scared to add any. <Good, do not add anything else yet. Check for ammonia, nitrite and nitrate. Do not add any more fish until ammonia and nitrite spike and crash to zero, and nitrates are rising. Until then daily partial water changes are called for. After your cycle is established you can adjust your water changes to keep nitrates below 20ppm. Keep your stocking level light. As you are seeing, that Pleco alone adds a lot of waste to the water. Heavy filtration is called for, but NOT undergravel filtration. Don>   Thanks! Dayna

Plan of attack for very soft, very basic tap water Hey, WWM-ites, <Hi Glen> I've seen lots of advice on what to do with low pH, soft water, and what to do with high pH, hard water.  We have high pH, soft water - details in a sec - and I'd appreciate your views on what I think I need to do. <Okay> Our tap water is pH 9.8-10, according to my newly calibrated pH meter (and in line with what the City reports).  Alkalinity is around 60 ppm, according to Austin's water quality report, and total hardness is 85 ppm.  Those are both in line with what I get at the tap with my strip-based test kit (GH registers ~75 ppm and KH between 50 and 80 ppm) and my reagent-based test (3 dKH).  (Hey, I'm an engineer - there's no such thing as too much testing or data!) <Agreed> We have a standard 55g tank and Emperor 400, and are three weeks into cycling it for a freshwater community tank.  We won't put anything into this one that requires weird water - tiny fish (Endler's, Tetras, Otos, small Corys) and a trio of Swordtails - so I set the tank up with water adjusted to a neutral pH, using sodium biphosphate (don't remember specific product or manufacturer). <Not important... all the same molecule> I started using a phosphate-type buffer to get it stabilized at 7.0-ish, but will stop using the phosphate buffer because we're going to replace most of our plastic plants (and some silk ones) with the real thing.  We have some petrified wood and "pagoda stone" (both tested pH neutral) for caves, and will be putting in a small piece of driftwood for the Otos.  Temperature is set to 77F.  1.5-2" deep small gravel for substrate. <Okay> Here's my approach to the water.  Please let me know if there's something I should do differently: 1.  20% water changes once a week, with substrate vacuuming. 2.  Dechloraminate 20-25 gallons at a time (in a dedicated new trash can) - easier and more uniform to treat a bunch all at once. 3.  Bring the pH down to 7.0 (using the sodium biphosphate product (anything better?)). <Mmm, in the long-er haul? I'd be looking into a reverse osmosis device... actually I would (and do) use this for your general cooking, drinking purposes as well... better for you> 4.  Boost the KH and GH into more the 125 ppm range using calcium carbonate.  (Would something else, or a different value, be better?  If we actually adhere to this rate of water replacement, does our tap water need additional buffering, or is the little bit that's there going to be enough?) <I would likely leave the present buffering, calcium as it is out of the tap... if you get, use RO or DI (or both!) you might want to supplement here> 5.  Aerate and tweak temperature overnight before a water change. 6.  Judicious chemistry monitoring between changes. <Sounds good, very thorough> Since RO water still needs to be tweaked with pH adjustment, buffer, and essential minerals - why not adjust the tap water? <Mmm, let's see... just easier to start with less stuff in it... more consistent product...> Also, I bet the pH of RO water around here is still quite high, given the tap water to start with - I'm going to get a gallon on the way home and test it. <Should start out near neutral to slightly lower than 7.0...> Also, since the tap water is so soft to begin with, the double-whammy of a buffer and an acidic product shouldn't have too much impact on osmotic pressure, right? <Correct> Thanks again for your help! Glen <Thank you for your involvement, sharing. Bob Fenner>

Re: Low pH Levels Hi Bob Thanks for the quick reply to my question. My tap water runs between 5-6 dKH, my aquarium water is near that, testing between 4-5 dKH. <Mmm, a  bit low... recommended that it be 10 to 12 dKH or 3.5 to 4.5 mEq/liter or 175 to 225 ppm...> I understand that gravel is a source for acidic activity, but I do clean it regularly with my water changes, <Mmm, the biological activity that results in acidification occurs whether the gravel is cleaned to a large degree> I use the Anaconda water siphon kit to accomplish this since I am dealing with rather large amounts of water. <Good idea> I have heard of aquariums with no substrate at all...do you recommend this in order to reduce the acidic activity? <Not in general... there are set-ups, reasons for some designs to do away with substrate/s, but the vast majority of aquarium systems are bettered by having them> As for the gravel currently in use, I have no idea as to its calcium content. As with all gravels I have seen at the local fish stores, it is merely labeled Mexican beach sand (gravel) or some other non descriptive label that doesn't give me a very good insight as to its actual chemical makeup. <Can be tested relatively easy... most simply with a bit of distilled or good RO water adding a bit of gravel, checking the resultant pH, alkalinity in a day or two.> This gravel is of varying sizes and colors and looks rather good in the aquarium, which was my primary reason for choosing it. If you can recommend a particular type/brand, or perhaps an online site that has a more complete description of its products, I would be sincerely thankful now that you have given me a clue as to what I should be shopping for. <At this point, I would add the more alkaline crushed material to your canister, add the baking soda to your change water... leave the gravel as is> As for the decor of the tank. I would love to add some rock(s) to the tank, not only for decor, but the fish also seem to appreciate having someplace to "hangout". <You are correct here> Would it be possible to give me some tips here on what kind/type of rock(s) I should consider adding. <Again, the simplest assay is mentioned above> Once again, it has been my experience that these things are displayed at the local fish store, but are seldom labeled as to their type...limestone, marble, or whatever. <You might even "collect your own", or check a local garden, rock and block supply outlet...> If you know of an online site where I could shop for these things, it would be most helpful to me. Locally there are only a couple of fish stores, and they are somewhat small with a limited selection of materials. <Dr.s Foster & Smith have about the best selection of aquarium supplies outright... seem to be fair priced, consumer-oriented> One other thing...I currently only clean my Eheim canister when the flow begins to bog down...maybe every eight weeks or so. Would it be helpful to clean it more often? <Mmm, yes... about once a month... a good idea to incorporate their Grob Flocken or such, or two "pads" that you can switch out just the outer, dirtier one, move the older into the "number one" position... to preserve nitrification> I read somewhere that flow should be your guide on this, but would be interested in your thoughts. <Better to not wait for diminished flow> I would like to thank you once again for your expert advise, and taking the time to share your knowledge with those of us with a somewhat...umm...lesser understanding. Randy <Glad to share, be of service. Bob Fenner>

Buffering Fresh, 2.1 >Marina, Thanks for the advice. >>Quite welcome. >!ST bubbles from the bubble stones, not the powerhead. >>Gotcha, so you've got excellent oxygen/carbon dioxide (O2/CO2) exchange. >I did check KH and GH.... both WAY TOO LOW...... so I guess the best thing to do is to find some of the Seachem products. I do like Seachem best, as I said.  The products were quite easy to find online, and relatively inexpensive. >I have read that clown loaches do much better as a pair or more? Is that not so? >>They may be a bit happier, but honestly I've never known them to do poorly if kept singly, either.  They can grow quite large, though, something to consider. >Thanks for all the help. Monica >>Again, very welcome, I'm glad I was able to answer your questions.  Marina

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