If the kalk is added as a drip, that helps reduce the pH shift, as does aeration. Using kalk to raise calcium and alkalinity tends not to work, though, because the pH of limewater is so high. I'd use baking soda and a calcium chloride product, like Turbo Calcium, to do the job.
This article covers lime in detail:
http://www.reefkeeping.com/issues/2005-01/rhf/index.php