gizmo wrote:

Hi Dave,
I use aeration during the night.
I just started using a pressurized CO2 system one week ago which is already
proving itself!
The ph is steady at 6.8 and I also think it is very important to keep the
tank aerated when light are off in order to prevent big PH drops when plants
also eject CO2. It is also a factor depending on your fish stock and
size....

The "big pH drop" is exactly 0.2 in my tank. Measure it and see. Unless you have
a fish overstock, the aeration at night is unnecessary.