pH rises...What causes them?

[GrayLadyPat]

Hi, everyone....

I have had tanks for a very long time with a lot of different types of fish. In general, once you change the water, the pH falls slowly until you change water again, because of the actions of the bacteria, decaying food/egg/dead fish that one might miss. In a discus tank, it is not as noticeable because of the frequency of the water changes. In fact, if you change the water often enough, the pH doesn't change much at all unless you have something really catastrophic happen.

So, here's my question:
My water is relatively acidic straight from the tap at around 6.5-6.7 depending on whether the local water supply (a large reservoir) is doing its seasonal turnover. In the tank, it runs a pretty steady 6.4, although I had to add some crushed coral to keep it from falling too quickly.

Barring anything new being added to the tank, what would cause normally falling pH to rise instead? I've not ever had it happen before in an established tank.

The only thing I have changed in my tank is that I have dewormed all of the residents. After the deworming, I made a good sized water change, and everything has been relatively normal. This morning when I tested the water, the pH had risen to 7. Nobody is showing signs of distress at this point, and a scheduled WC is due for this evening. My tap water tested at 6.6 immediately after testing the tank this morning. The date on my testing chems is March of 2013.

Ideas?

[harry-ab]

Did you use some medication that contains Praziquantel? In this case, i sugest this is your problem. Actualy, not a really problem. Discus are not that sensitive!

[GrayLadyPat]

Ah, yes... that was it, then... I used Prazi...with repeated water changes, it should fall back to normal, if that is indeed the case.

Thanks!

[ROOK45]

I would think you have to decrease the amount of crushed coral and test regularly till your desired PH is reached.

[TURQ64]

With a lot of years practicing what I preach, I've honestly never,if ever have seen ph spikes to the high side.Maybe in an aging barrel, but not in the tank...My 2 cents; not sure what the crushed coral is even doing in the equation. With frequent wc's, 'stabilizing' ph for crashes is textbook garble...in 24 hours, slightly acidic water will only become more acidic from bioload (and mostly negligable in 24 hours)...Discus will live in all types of water hardness, but they will tolerate way lower 'ph values' than most other hobby fish. Outside sources of alkalinity are the only way for it to rise instead of fall..(providing it was aged for gassing off, or RO, which is already free of hard ions..)..using a water softener?

[GrayLadyPat]

Actually, I think the problem is not what I am doing. It is the water source.

I was talking to someone else a bit ago, and it dawned on me that our lake is doing its annual turnover. For those who don't know what it is, here's a brif explanation. When the air outside cools, so does the surface water. It sinks, forcing the warmer water from the bottom to the surface where it cools, and sinks again. The water at the bottom of the lake has particulates and other things that normally don't make it into the city's water except fo that one or two months out of the year. In the spring and summer, when the air is warm, it isn't an issue.

Well, since we are going through our turnover, the water company is adding more "stuff" to combat the dirty taste in the water, so a bit more aging and offgassing is in my future.

The crushed coral has already been removed. It was there to combat a pH crash from an issue I had before discus.

As soon as the lake settles down, my pH will as well.

Cheers!

[Len]

I can see that being plausible. By the time the water comes from its source and through your taps, it is what it is. Regardless of any extra "stuff" has been added to it, the composition of the water isn't changing between there and your tank unless you add something yourself. The two things that are probably making the ph rise are the fact that it is off gassing CO2 as well as the crushed coral you had added. Both of those things would make your ph rise somewhat. Like Gary said, though, even if your water normally drops ph it is going to be insignificant in 24 hours. Your water should be fine for discus, and chasing parameters (especially ph) will become a never ending cycle.