I set Co2 level based on the contents of KH.
I have a constant content of KH, and CO2 dosing by the computer (PH probe measures the pH contents and sends it to computer. The computer is connected to the solenoid. Solenoid valve opens or closes as necessary) I set ph range that CO2 content were located in the green field. For example if I have KH=8, then i set ph to 6.9-7.2. To dissolve CO2 i use a separate filter located behind the main filter.
PS. Quartz stone - I mean a small gravel, not big stones. Bucephalandra are attached to big pieces of lava or wood.