QI had these same problems when dosing Kalkwasser with two part. The Kalkwasser wasn't consistent in keeping stable parameters as evaporation rates can change. Anyways I dropped the kalk all together and just dose 2 part now. I bake my baking soda to maintain PH.
Currently I dose alk and calcium every hour each separated by 30 mins. My calcium never various from 430 and my alk 8.0dkh.
The high alk could of caused the STN some people notice when running biopellets this happens. I'd drop the Kalk and then figure out how much 2 part u need to dose. This is also a good read if u haven't already.
http://www.reefkeeping.com/issues/2006-02/rhf/