Stony corals do best with a Ca eeactor that dissolves aragonite with acidified (CO2-saturated) seawater, it supplies everything you need, and once set up and tweaked, is the least maintenance-intensive item on your weekly list. It definitely does the best job on maintaining both alk nd calcium when correctly set up.
Ditto on Andy's stuff through MRC, after using a few other products on the market, I settled on the MRC line of products for quality of construction and reliability of design. Establishing a Ca reactor is not cheap, but running it once you've acquired all the equipment is the least expensive of the mothods out there while delivering the best possible supplementation at this point in time.
HTH