I've had a Neptune AFS mounted on my sump, directly above my return pump for about 6 months now. I have the pump ramp up a bit when the food drops, just to make sure it all gets sucked in and blown into the tank. Works perfectly fine. Supplement frozen food most days as well, also by dropping in the return chamber. It gets blown into the tank bit by bit as it thaws, I think it gives the fish a little enrichment vs just dropping a cube in the display.