I am currently involved in a discussion regarding the pros and cons of keeping a DSB or any SB in a refugium for a reef tank. It brings to mind a frag tank. I just broke down my 45g reef and transferred everything (except some LR) over to my 150g reef. I have set up the 45 as a frag tank. It has a refugium area that was in use when the tank was a reef, but now it is bare bottom with only about 20lbs of LR I had no room for in my 150. Thinking the tank needs the bio filtering qualities of the rock (it is on an opposite light schedule than the display) I feel glad to keep it there. BUT, and here is the question, does the tank need the SB in the fuge if it is a frag tank that has mainly sps frags in it? How do others run a successful frag tank? I am running a skimmer also, of course.