Why do you need CO2? Doesn't seem like a lot of plants. This will probably make me sound like a simpleton but my ph dove down and I added an airstone and it was back to seven the next day.
Perhaps I should just remove the CO2 and see what happens. I have plenty of aeration, I had a PH of 7.5 then for some reason it dove to 6.0. I'll remove the CO2 and see what happens.
