have new tank-55 gal. 6wks old-few hermits -few snails-couple firefish-35#live rock-couple frags-tube anemone-slug--and an orange starfish that looks like it is falling apart-lost part of 2 legs-and looks(bubbly)?any ideas whats wromg--s.g.-1.0235 ph-8.2 no ammonia ,nitrites or nitrates thanx