On my 240 gallon tank, I have two return pumps, one is 2000 litres an hour, the other is 3000 litres an hour from my sump. I cut a piece of pvc pipe grinded slots into it so the water flows through, but not the pellets. I also have two power heads, one a 700 liter per hour, the other a 1500 litre per hour, the smaller I attached to a piece of flexible rubber tubing and put the tube right against the over flow, so if the food gets sucked against the slots I cut, it now gets blown straight away, with help from my wave maker, to the other side of the tank. No problems anymore 