Kalk Dripping in nano reef

I'm going to start dripping kalk into my 5.5 gallon (Fluval Spec V) reef tank to help stabilize my calcium and pH (I have low pH problems also) I can't add kalk through my ATO because it would end up dumping in too much at one time so I've already set up a kalk dripper from a 1 gallon milk jug with 1 tsp. of kalk added. I'm going to completely get rid of my ATO as it causes such unstable salinity swings as it dumps fresh water into my tank. So I'm Going to rely on my kalk dripper to replenish evaporated and dose kalk. But the problem I'm having is figuring out how fast the drip should be to make up for evaporation but not overdose my tank with Kalk. Any suggestions?