PH so low it kills my fish. How to raise it?

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Glte

Aquarium Advice Newbie
Joined
Sep 26, 2004
Messages
5
Location
Ohio
I seem to have an odd problem. My water is medium hard, gh 11 and kh 8 with perfect ph right out of the tap. However, the ph soon drops to the quality of battery acid and stays there. I cannot bring it up with chemicals. Once I used almost an entire can of PH Up and it did nothing. Not to mention that fluctuating ph is terrible for the fish. I have lost so many fish that I don't even want to think about buying more until I am convinced that the ph is in an acceptable and stable range. The thing is I don't know how to raise it properly. My primary tank is 55 gallons. What will bring the ph up to a level that will be safe for fish and stabilize it? Also, can anyone tell me why the ph drops like that, it is because of the kh? I thought a high gh and kh kept levels stable? Thanks in advance for any ideas. :?:
 
Welcome to the board Glte. You're right. It's very unusual to have that high a KH and a falling PH. If it were my tank, I'd go ahead and place crushed coral in the filters anyway. It will at least start to raise the PH.

How often do you change water and how long has this tank been established? The biological processes forcing the PH down are from waste produced by both your fish and nitrifying bacteria.

Sorry that I won't be around for a few days to respond further to your posts. I'm sure some of the experts here will be able to continue this with you.

GL
 
Thanks for the welcome and your reply.

I've had this tank almost two years and a smaller one almost four years. But the longest I've been able to keep fish is a couple of months and only by changing 50% of the water every week at that. Once the ph gets out of hand I can't bring it up to a safe level and once all the fish die, it's usually so bad that I have to empty the tank and start over. I know it isn't good to do this but if I don't get the poison water out completely the acid is already to high from the git-go.

Usually when I start a "new" tank, the ph is acid in one week. I'm talking bright yellow in the test tube and off the chart. I just don't understand how this can happen so quickly.
 
Your KH number does not jive with pH. Assuming that your pH is 7.0 out of the tap, your KH would be almost zero assuming atmospheric CO2. <This is according to Henderson-Hasselbach equation, assuming a carbonate buffering system>

If your KH is actually 8, at atmospheric CO2 of 3, you should see a pH of 7.8.

I see 2 possible reason for your reading <anyone see any more?>
1. You have CO2 in your water - 24 ppm according to my chart - This is quite common if you have well water. The CO2 comes out of solution in a day or 2 & the pH rises. To test, take wter from tap, measure immediately & 24 hr later (in a cup open to atmosphere - not in fish tank).
2. There is something else in the water other than carbonates that is acting as buffer - eg nitrates, phosphates ... often seen in agrucultural area water. The presence of extra buffers takes the whole KH/pH relationship out of kilter. So, even if you are measuring KH of 8, you actually do not have any HCO3 in the water as buffer ... This might explain the pH crash in spite of your frequent water change ... You are using up all your carbonate buffers, & the pH crashes.

One way to find out is the check your water co's water quality chart & see what else is in the water. If there are lots of stuff other than Ca & carbonates, I would be tempted to use RO or some other source of water.

In any case, the behaviour of the tank's pH indicates a low buffering capacity/zero KH water. You will need to add carbonates to the water to keep it stable. Crush coral will help, but will be slow. You might be better off adding sodium bicarbonate == baking soda, in addition to the crush coral.
 
Got my ph kit out. It reads about 7.4 out of tap or in the Basic range. My water is from the county supply. There is still some agrucultural activity here so maybe that is a factor.

How much baking soda is to much. The tanks are empty so it isn't like I'm going to kill anything.
 
Crushed coral or aragonite in a bag, added to your filter, or used as substrate, is a much better idea than baking soda, which will break down too quickly. This will cause a constant pH swing--not good at all for your fish.
 
How much crushed coral or aragonite should I use in a 55 gal tank? Sorry if I'm asking dumb questions but I've never had to deal with this problem before. I've had fish for many years but I never had water like this before I moved here.
 
I use CC in my filter for my 55 gal. I use about 1.5 cups in a mesh media bag in the canister. If you have an Emperor HOB they have media baskets that can hold crushed coral.
 
Glte said:
Got my ph kit out. It reads about 7.4 out of tap or in the Basic range. My water is from the county supply. There is still some agrucultural activity here so maybe that is a factor.

How much baking soda is to much. The tanks are empty so it isn't like I'm going to kill anything.

baking soda is useless, don't waste your time. Just use crushed coral or oyster shells. Baking soda is only a temporary solution and wears off just as any commercial Ph altering chemical does. Once is wears off then the ph just goes back to normal and is actually worse than just leaving the ph as it is. NEVER use any temp. solution to ph problems, it will only cause more problems. Find something to buffer the ph and keep it constant.
 
Baking soda temporary??? I think there is a misunderstanding of chemistry here. It is true that HCO3 will react with acids & be gone. But this is what a buffer is supposed to do. This will happen with CaCO3 (ie crushed coral) as well.

The pH swings when you don't have enough HCO3 in your water.
With enough HCO3 your pH will stay at the equilibrium point of HCO3 (mid 8's), and not move with either adding acid or base... ie the system is buffered.

KH in a pure carbonate system is measuring your HCO3 level. Weather you add the HCO3 as baking soda or crush coral is immaterial. Bicarb is bicarb, no matter what source it comes from. Just that NaHCO3 dissolves faster (like in minutes rather than weeks as in cc). The only advantage with CC is that there is Ca, (this is GH) which is important if you are growing coral (or snails).

I refer those interested to:
http://www.advancedaquarist.com/issues/june2002/chem.htm

Also, the recipe for adding baking soda plus basic water chemistry is found at the KRIB FAQ here:
http://fins.actwin.com/mirror/begin-chem.html#reference

<PS - I think this is the best resource for aquaria on the web>
 
Would Arag-Alive Aragonite Reef Sand work? My local fish store has that in stock and said it would but I don't know if they know what they are talking about - bunch of kids working there . :?:
 
Aragonite would help quite a bit, but I see better results when the buffering media is in the filter, with water flowing over it. That's why I am such a fan of CC - it is also not dependent on attention with water changes, so that is a plus for busy ole' me!
 
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