no power head, but i have two 3W pumps (50gph each),one for the waterfall top left and the other splits into the moss drip system. I originally had a 5W pump (100GPH), but the pump was defective and causing a rattle, i haven't replaced it with a higher flowing model yet.

both pumps are covered in filter media, I used these rocks. i tried to seal this compartment off from livestock, but shrimp are like the aquatic version of roaches, they can squeeze anywhere. I often see them chilling on the filter media chowing down