Agree. How long has it been since your swap. What kind of fish? I only have 2 hermit crabs in my 215. They tend to knock corals over that arent glued down as well as kill snails for their shells, even if they dont take the shell. I have extra shells for them to grow into if needed. I would just blow your rocks off with the turkey naster 2x a week depending how bad it is. My hair algae outbteak was real nad for some reason after i moved. I was blowing the rocks off 2-3x a week and feeding real lightly. Idea is to remove as much of the food source (detritus) that the algae feeds on. Also, brissle tooth tangs do good at cleaning the rocks (kole tang comes to mind) as well as shortening your time the lights are on.