Your corals certainly are not using that much calcium. Some will disagree here I'm sure, but in my experience when you use calcium chloride in an unbalanced way as you are then you tend to precipitate out alot of calcium and carbonates (i.e. calcium carbonate).

My suggestion would be to do some fairly decent water changes to get things back in "balance" and then go to using just a two part additive like B-Ionic, C-Balance, or both parts of Kent AB. If your a DIY'er then you can make your own. The recipe is in the REEF CHEMISTRY forum on RC or just get with GaryP for it.

I think anytime your going to rely on calcium chloride as your main source of calcium additive you will need to do more than the ~10% per month that you are doing. Probably weekly 5% or monthly 20% water changes. And then maybe double that percentage every 4 -5 months.