If you divide your kh ppm by 17.9 it will convert it to degrees or dkh. If 120ppm is your kh, it would be 6.7 dkh. If 250ppm is your gh, that would be 14 dgh.
KH 8, PH 7
co2 24 ppm
co2 is diy, diy diffuser (powerhead with gravel vac tube), this method is more effective than the plastic ladder diffuser that I had been using previously.