hi,somehow 'aquarius' posting seems more of what i am facing with. these white organisms looks harmless. i have this magnetic glass cleaner near the top and whenever i let this magnet float, u can see hundreds of these white things dispersing in the water. some are actually sticking and moving on the glass itself. so far, i cannot see my wrasses, clowns and trigger feeding on them , thus i don't think they are tasty enuff. i don't have those giant clams but i did have some hermit crabs and small clams that died long long ago.