karen99

Is there anything that could cause pH to drop from 7.8 to about 6.8 in a day?
The tapwater here is 7.8. The tank's pH was 7.8 for a week or so with diy CO2. Then one day it was suddenly around 6.8-7.0.
I suspect the pH drop killed three of my fish. Some of my other fish appeared extremely stressed after the pH drop and seem to be slowly adapting and recovering now. I've been doing very small waterchanges with aged tapwater which is slowly bringing the pH back up.
But I am curious as to what the reason could be for the pH drop, so I can avoid it in the future.