i want to know if i got this (finally)!!! my 80 gallons of water in the 90gallon tank has a Kh of 1. between 15 and 20 mg/L CaCo3 before lights on, with a new pair of calibrated pinpiont ph probes, one on each side of the tank ph reads 6.45 and 6.44 the tank also has a grounding probe in it. 1 hour and 15 min before lights on, co2 turns on. when lights come on ph is at 6.09 and 6.05. this tells me (if im right that i have close to 30ppm co2) as the photo period goes for its 9 hour cycle the ph drops to 5.95 and 5.89. this is OK, right? do i have this? or is co2 to high ? i remember reading something about the kh shifting slightly when lights and co2 start but i'm fuzzy on what that was.. can anybody clarify?