Water Changes And Swinging Ph

[karin]

Hi.

Have a new 60 gallon tall tank, recently cycled... 3 weeks ago, started adding fish. Test every day because it is a new tank and everyday, Ammonia 0 Nitrites 0 Nitrates 40-80, Ph 7.6. Temp at 78 F. Doing 20-30% water changes every 5 days. Using a UV sterilizer to get rid of a green water issue after I planted tank up about 3 days ago. Water nearly clear. No spikes of any sort. Using API test kit.

My tap water has a Ph of 8.2, but the tank stablizes at 7.6. Well I'm wondering as I do my water changes, that tap water must be causing a Ph swing and I'm wondering about the potential impact of that. Right now I have an young (1 inch) Angel fish that was fine for a week and now is gasping for air at the top and not eating. Other fish (3 congo tetras, 4 cories) are fine, active and feeding.

Not certain what to do about the angel. Thoughts on the ph swing?

Thank you.

 

[OldMan47]

A pH swing of that magnitude is not a problem for any fish but a significant change in mineral content of the water could be. If you are having problems with the angel looking stressed, I would suggest that you need to do more frequent smaller water changes. Because the pH scale is a log scale, changes in pH may be much less dramatic than you are imagining. Try measuring the actual change next time you do a water change and don't forget the dechlorinator for the new water.