It all depends on how much you have in there now. You need about 1-1.5 lbs per gallon.. Dont skimp on the live rock. It is great for filtration. Good Luck...
yes i would have to agree..LR is very good filtration..in my 50 i started with about 40lbs..then i added more to have about 60lbs..and there is a huge difference..i even took the skimmer out for a little bit before i sold some of my LR to a friend..now i have about 40lbs again
Maybe you could add some larger pieces across the top to add some caves and crevices for your fish to hide. My firefish loves all the caves that I built for him in my 30 gallon.