Having fish poop collect under difficult to reach area just sucks. If you there is enough area to easily get the poop in the far back corner and have it not seen by other folks ( you know it's there so you can easily remove it every few days/week), then make sure that there is flowing water to the far end bottom (opposite end of the loc line) front pane of the glass.
Maybe i could adjust the water flow with the controller to 100% and see if that works too cuz it will constantly move more water, i have only at 60%. Cuz it is too much for cichlids and i dont want them to be affraid to leave their caves, cuz of the water flow,