calcium troubles

[martym]

Here's the story. For the first 3 months my calcium was around 400ppm, alk was low around 3-4 dKH and PH was low around 8.0. I was adding KH super buffer by seachem to try and get the alk and PH up. Calcium never changed. I had no luck. Started to dose Kalk by seachem. Ph and Alk whent up 8.4 and 12 DkH calcium dropped to 200ppm. Been adding Reef calcium by seachem for the past 4 day doseing max amounts Half in morning half in evening can't get calcium above 270ppm. I though Kalk was suppose to maintain calcium, not drop it What did I do wrong, and why won't it come back up? Is there a different calcium that works better than seachem?