I recently purchased a Kent Marine Bio-Rocker a week ago for my 240 gal that i am setting up. Will a air pump will be needed even though the filter is designed so that it maximizes the amount of air the water its is exposed to? I might buy a air pump in case my fish don't get enough air. Also, what kind of a pump should I get?, because my tank is 24" deep and that I never have dealed with this big of a tank before.