I have a coarse sponge before the return bay and keep a power head running in it to keep anything that gets through stuff suspended so the return pump gets it. The bottom of that bay stays pretty clean. That works well enough that when I'm in a hurry, I just drop frozen cubes in that bay to feed the fish.I find the bottom of the return bay really gets caked over with gunk but there is so much little creatures in this section I have to think they live off the gunk at the bottom.


