7kh is fine Randall, i actually prefer low kh if ur system is low on fish and nutrient! For your question, if you increase the effluent drip rate it will also decrease the back pressure in the chamber which will in turn allow more co2 inside the chamber and yes it will bump up the kh/cal. Like Brian said, it's better to set and forget tbe effluent drip rate and only mess with the bubble count! Whats ur po4 ??