You should add Calcium+ to increase the Ca, Kalk is mainly use to maintain the level.
You will also need to add Kh+ at the same time. But pls note that using such manual dosing, the Kh and Ca is inverse relationship (that is increase in Ca can led to Kh decrease if overdose). so increase them slowly.
For kh of your tank, you should buy Baking Soda, cheaper.