I just set up a 55 gal reef tank that's being filtered by 2 HOB filters. I will be switching to a sump sometime in the hopefully near future . From my research its appears that for a refugium to do any good it needs to be really big. Most if not all sumps that would work for my tank have refugiums that are just too small. The owner of my local FS said for a refugium to be effective in my tank my sump would have to be at least 50 gals. What do you guys thinks?