GHL Doser 2 with 4 pumps used with Triton Method.
Very easy and hands off type of system.
I would recommend basing your build around Triton from the start if you decide that's the way to go.
It's easier to do now than integrate later, especially since you need a sump designed specifically for Triton with your tank's drain(s) dumping directly into a large refugium.
OR
Calcium Reactor with a Cole Parmer Masterflex pumpwith EZ Load head (used from eBay) and either an Aquarium Plants Carbon Doser Regulator or a custom built (from eBay parts) dual stage regulator for non-Triton tanks.
Also a pH monitor for the effluent.
This setup costs more, but makes using a calcium reactor super easy.
But as JenReefer said, if you are just starting out you could get away with just Kalk in your ato for now and get the CaRx setup later once your Alk and Calc demand really increases from increased coral growth.
You can check out my build thread (link in my sig) to see an example of a Triton system, and check out the Triton more.