I have always used a dosing pump. calcium reactors are only for calcium and really does not help with alk. In a sps dominated tank alk is key and sps us more alk and mag are used I noticed that cal is used up but not that much. dosing pumps are the best way to go and testing 2x a week is key , once you notice a drop in alk make adjustments asap. aslo alk affect cal , in your alk drops its will take you cal reading along with it . always ajust alk first and then in 24h rest cal it will always return back to its normal reading. dosing pumps are key for sps tank , most people with cal reactors still have dosing pumps for alk and mag. The more stable your tank is the faster growth you will get....