Thanks all, I think you may be write about the sand. I did wash it, but I didn't. dry the sand. What do you think I should do now. I hate to tear it all down now. The only fish I still have is 2 Blue Damsels, 2 Clowns and 2 large Coral Banded Shrimp. I heard that the Shrimps could start eating other fish as they mature?