I just noticed my PH has increased to 7.0 from a steady 6.6 .
My pressurized CO2 bubble rate has gone down considerably and no one has touched the settings.
I have Reg Grigg's BDR with an Ideal Valve.
Tank (10lbs) is almost totally full, low pressure is the same.
The only thing that has changed is outside temperature down 6-10 degrees F, and have allowed my KH to go down (have not added baking soda at water change) to 53.7ppm (3 degrees).