Thx to anyone who can give me some insight. I have a 36 gal bow tank, 1 betta, 5 Danio and 5 Tetra. Biomaster 350 with a Fluval 3.0 LED. I'm having trouble with the correct application of pressurized CO2. I have an American Marine PH controller that is reading my tank at a steady 6.4 PH. My water out of the tap is much closer to 7. MY KH seems to be around 4. I have a large piece of driftwood in the tank which may be lowering it. The problem is, the PH is so low that the controller won't inject any CO2. I'm nervous about lowering the threshold much past 6.3 for the health of the fish. I have the controller plugged into a timer that turns it off at night as I don't want to inject at night. I thought there would be a much greater PH swing at night, and that the controller would have turned on this morning, but there didn't seem to be much of a PH rise overnight and I'm a bit confused as to why. Any idea's?