I have a Fluval FX5 that I run until the flow slows down I only put black bio stars and porcland beads in it and I do a three quarter water cange every week and vacume the gravel. I have so much bio in the canester fillter it dosent throw off my cycle and my tank is over crowed it is a 150 gallon tank. If anything I should put a large aqua clear fillter to pick up more waste on bottom. I also use the pads on sides of canaster