I am going from 2 emporer 400's to an FX5 on a 75 gallon tank with an oscar and jack dempsey, 2 bristlenoses(1 albino and one long finned) I have been reading a few things about what media people use, and I think I am gonna use the scrubbies in the middle tray(is stainless steel ok, or should I use the nylon ones) and probably bio-max on the bottom, what is the consensus on the top tray, the initial filtration, anyone??