Adding Kalkwasser?

Usually, you mix up a small amount of kalk powder with RO or RO/DI water, let it sit for a while, and then begin a slow drip into the sump. This method can dose kalk and take care of top-off at the same time. Exactly how much kalk powder per gallon, and how quick of a drip, will depend on the results of your water tests. A little trial and error and you'll have it all figured out.

Hope that helps.