Imo, it sounds like you have a lack of beneficial bacteria in the tank. I think adding established LR or LS would help your tank maintain and cultivate the bacteria. Like Greg, I had a tough time keeping sps when I first set up my tank till about 9-10 months in. The new rock + sand just didnt have enough to keep sps(i believe). I could grow softies,lps,zoas,ect...but when it came to even caps they would bleach out and die after a few weeks. Now I cant get rid of some species that grow out of control. its up to you...JM2C