What time of day is it best to switch on an air stone.i have two air stones and i have plants.the man in the local fish shop said it would be best to turn on at night because the plants make carbon dioxide at night reducing the oxygen in the water. Is this right?
No worries about the plants. Only reason it would be detrimental to plants is if you are injecting CO2. If not, it will actually help you keep the tank at equilibrium with atmospheric CO2 (usually around 7ppm).