we have a 100 gallon tank with a build in filter in the back with the bio balls. My question is should we keep the bio balls in their if we are going to use it as a reef set-up right now we have 67lbs. of live rock with a 3in sand base with 9 small (damsels,blenny, gobie, clowns) fish, 1 shrimp, 6 snails, 5crabs, (I know we need more snails and cleaner critters)