I am having a problem with red slime algae. Used chemiclean 4 months ago and it worked. Told blur legged crab eat itor snailbut No Crab ate snail for shell. And I had replacement shells of all sizes. Someone said a sea urchin but read they will eat my corals, that isn't going to happen. Is there a plant that will help or do I just have to vaccum it out as best I can or a fish maybe.