Kalk how to use it and should i?

[Tarolisol]

Well with my new tank almost ready i have a few questions. First off, to keep calcium stable what should i do. I figure kalk in my top off water, which will be gravity feed to a float switch in my sump, but could someone explain kalk to me how it works what it does and how to use it. Also will it keep my PH stable? Also is there anything else i should add. I want it to be mainly SPS. The tank is a little over 200 gallons with about 50 gallon sump and 45 gallon refuge.