[goinpronhl9]

I have had a 55 gallon tank set up for several months and have about 30 lbs of live rock and 4 damsels. I have started seeing some signs of "crud" algae in the crushed coral substrate as well as on the glass. Is this a good sign? or should I get a "clean Up Crew"? If so what would you reccomend and how much would I need for my size tank? When I first set up my tabk I made the foolish mistake of gettin a sand sifter star which most likely starved to death shortly after because my tank was not fully established, and recently I had a scooter blenny die which seem to have starved as well. Would buying a clean up crew now lead to the same result or am I just buyin the wrong specimens? Also I have been reading about Sumps. Is that necessary for a fish only aquarium like mine? And does any one have any thoughts on quarantine tanks vs freshwater dips? Thanks For reading and I would appreciate the help Im tryin to do my research and avoid making any more dumb mistakes!