90 Gallon Wet Dry questions

Hi,
I have a 90 gallon Tru Vue 18D 24T 48W with center overflow which I have struggled over the last four years to filter properly. It drains into a wet/dry sump which I have sealed per Tom Barr. My overflow uses a durso design and I have a secondary overflow and a valve to quiet the flow. The wetdry is powered by a quiet-one 2200 (594 gph) which dumps into a DIY co2 injector (Thanks again Tom) I also added a Fluval 404 (wouldn't buy this again ) to help clean the debris at the base of the tank. The inputs from the quiet one are at either end of the tank. The fluval returns near the center. I have tried moving the pump inputs to spary bar at the top to vertical bars located on both ends and to inputs at the base of the tanks. I do weekly 50% water changes.

Should I up the pump to better force the debris off the bottom? It seems when the loaches eat they stir up so much debris that the tank can take a couple of hours to clear.
Or is it the location of the center overflow? Should I add powerheads to the bottom of both sides of the tank? I am also not against removing the center overflow and moving it to both sides (two overflows) I realize that will involve cutting out and polishing the plexiglass (which is black) but I have about had it with the cloudy water.

Thanks for any ideas