Okay, so I've been running this filter for a few weeks now. So far no problems. I'm wonderng though how necessary the foam pad is. Mine is already pretty cruddy and at $15 for a set of 3... what does it do exactly? It also came wiht a carbon pad but it looks so thin I threw some carbon in a bag and put it in one of the trays. Only trouble is, you can never get as much carbon for a 75 gal tank as they suggest in one of those trays. So should I keep using the carbon like I've been using and toss the carbon pad? Also, they say to put the carbon pad on top of the foam pad. Why? Does the foam pad block the carbon? If that's the case then I've been screwing myself because I've had the foam pad on top of the bags of carbon I've been putting in the tray.