For chemical yes, for bio NO. Emp 400's are crap. I say use fx5's and eheim canisters or a wet/dry filter.$INI$T3R;2993806; said:I have 2 emperor 400's and 2 Jebao 304's (340 gals per hr). It has four trays in it.. How should i set them up? Can someone tell me, exacty how to set the filters up (as far a where the bio balls go, the the pads)? I figured as long as i was filtering 12-1400 gallons an hour id be ok??!!??