Someone in here, can't remember who it was right now, put a rectangular piece of clear Perspex in the rear chamber, resting it on top of the pumps. That way, all the water going through the skimmer gate (with the debris) goes straight into the overflow cup, and into the sump filtration socks. This will reduce the amount of debris collecting in the rear chamber.
I use a wet/dry vacuum to suck the debris out from the rear chamber. A PITA, but.....