I have another issue. The fish poo and sediment is collecting at the bottom of my 75 gallon tank and doesn't appear to be taken up at all by the pump. I am using a Quiet1one 1200 which works great otherwise. The only other thing I have in the tank are air bubbles from a whisper 300. Does anyone have a recommendation for getting the fish waste into the pump? Or, am I missing a step all together?