[Sk8r]

The deal with kalk is you only have to tend to it when your topoff tank runs dry or you've used all your kalk.

I dose kalk from a garbage can of ro/di: I just dump in kalk and stir it up every time I add fresh water. Works fine...since my tank evaps 1 gallon a day. That means I can go two weeks or so without having to dose. Prior to that my tank required daily testing and daily dosing, even while using the ro/di to supply alk buffer---if I hadn't done that, I'd have been hand-dosing morning and evening to supply my corals.
You have to hand-dose to 'set' the alk and cal and mg levels, then rely on kalk to hold it there until mg runs out or kalk depletes.

Kalk works on reefs from 30g to 120g depending on density and demand of corals. Kalk works on 'voluntary' calcium uptake by ro/di water. Beyond that you may need the 'forced' calcium injection of a calcium reactor.