Stop dosing the Ca and Mg until the levels return to a level you desire.

Baking soda is the main ingredient in the Alk portion of the 2 part. Dose a little bit at a time or bake a box of baking soda in a glass or ceramic oven safe dish.

http://home.comcast.net/~jdieck1/chemcalc.html

http://reefkeeping.com/issues/2006-02/rhf/index.php
http://reefkeeping.com/issues/2006-02/rhf/index.php