I guess it depends on what size tank we are talking here. IMO, a two part system could work in a smaller system but as corals grow they become more "calcium hungry" and I'm not sure a two part system could keep up. Well I'm sure it could but I'm not sure your wallet could
I used Kent Liquid Reactor on my tank (90gal) for less than a month before I threw in the towel and bought a calcium reactor. Daily dosing was just a huge PITA not to mention having to test the water so often to make sure I had decent Ca levels. A dosing pump might be the answer for that one. I guess you'd have to sit down and figure out the cost effectiveness. My tank went through half a 64oz container in about 3 weeks so combined with having to dose it every day, I just wasn't interested in maintaining Ca without a reactor.