Frank,
My two cents - in my 150, I have a FX5 and a 305 running. Intake at opposite ends. Output for the FX5 at one end and the output for the 305 in the center, pointed at the end with no output. Circulation pump at the end with the FX5 output. Small circulation pump over the FX5 intake.
This creates a dead spot under the FX5 output - I placed a homemade filter (powerhead, water bottle and pillow filling) over the dead spot. The HMF picks up all the mulm - almost has to be changed daily. The water is always polished.
The tank is almost overstocked - 3 monster sized Oscars, 5 large Jack Dempseys, 2 Green Terrors, 5 large Silver Dollars, 1 small FlowerHorn, 1 large Pleco and 3 small Convicts. The Oscars are messy, messy, messy.....
Just the way I configured it.