[tang daddy]

I would have to agree aswell that a 10% WC would not effect the CA that much in a 55g tank, perhaps your sps is sucking your systems dose down. You should dose some more calcium to your system to maintain the proper levels. I currently run a 75g sps system and I am dosing 1 teaspoon of calcium powder every 2-3 days diluted in 1 liter of rodi. I dunno what that equates to with your current 2 part but it's alot of calcium.