well although i agree with predator 1 i dont agree that you cant over skim.when you skim you remove alotta crap but you also remove micro nutrients, noit a hole lot but they are beneficial. one way to combat this is to run a eco system filtration. basically large fuge packed with calupra, lr , ls, mm, dsb and only use a skimmer rated to half the system volume or run no skimmer. but still i owuld run a skimmer no matter what. in fact my skimmer is rated for 6x my system volume. i still run a dsb, fuge lr and ls.