Im in the process of setting up a 30 gallon freshwater tank which will have a few of those big fancy goldfish ( girlfriends choice ) , either that or an oscar so we decide to go with the goldfish , We sorta like those bubblehead ones ! Anyways I have 2 filter systems a UGF with a powerhead 170 gph and a penguin 150 bio-wheel , should I use both filters ? I have no problem cleaning under the UGF once a year or so but Ive been reading some bad stuff about the UGF . Thx all