I have been using tropic marin pro salt for a couple months now and I am battling recession on some of my sps. My magnesium is at 1200. My alk is 10 and my phosphates are very low. (under .05) I have been doing water changes and I am running a lot of carbon in a phosban reactor. For some reason I can't stop the slow recession on my corals. I am thinking about either pulling my sand bed and going BB or totally replacing it. Anybody have any ideas?