Ph rising?

[abs]

Hi all,

Just wanted to get your thoughts on what would be causing my Ph to rise? Tank is normally stable at 7.6 (same as the water going in at water changes) and two or three days later it is 8.0. :shock:
Its an 800L tank with gravel substrate, lightly planted, several pieces of driftwood and moderately stocked.

I can't think of any reason why Ph would be rising, if anything I would expect it to fall slightly between water changes! :?

Thanks

Abs

[JamezMan]

Mate I suspect its your gravel. I've had the same problems in one of my tanks. The ph starts at around 6.6 rises to around 7.6 by the end of the week. My gravel was just standard black gravel from a local fish store but unfortunately it has this effect on my tank so maybe its the same with you.

Jamez.

[gypsy3]

a good way to test if its your gravel, as kindly suggested to me by Merrilyn, is to put some in a bucket of water, test the ph, leave it a few days and then re-test.if its the gravel the ph should rise.if, as in my case, its not the gravel and the ph is the same, then its another scource. unfortunately, i still haven't found it :(

[abs]

Thanks for the responses. Tank has been up and running for over 6 months and this is the first time I have noticed this happening - do you think it's possible that it's suddenly just now started effecting my Ph?

[ktakeshi]

do you have plants in that tank?

[dwilder]

have you tried a test sample to make sure its only the water in your tank thats rising?if not try taking a cup of water set it out over night and see if the ph changes.

[abs]

Tested out a couple of scenarios;

1. cup of tank water
2. cup of tank water with gravel substrate
3. cup of aged tap water.

Didn't get any variations over 24 or 48 hours. :?

So I am none the wiser about what was going on there - good news is that tank has been stable at 7.6 ever since. :D

[FNQ]

If you use zeolite this can raise pH.