I have a 75 gallon that finished cycling two weeks ago. Its setup to be a fowlr. I have around 40 lbs live rock( 70 more coming in from Scott and Ray) and 80 lbs live sand in there right now. I use two emperor 400s, and 2 power heads as well. I decided to make it a reef . I am trying to find a sump/fuge with built in skimmer. What else do I need ?? Should I take off the emperors or leave them in ?? Also whats an overflow ?? Thanks !!