The system cycles all water through each section of the sump. The return pump is a MAG12 and is pushing around 820GPH in this configuration. I have a Seio 820 stream pump in the display as well. These two pumps accomplish my wave generation by directing the stream to intersect in the center of the tank.
The skimmer is powered from a MAG 5 placed in the overflow compartment on the inlet of the drain tube that connects to the skimmer. This provides a way to harness the potential energy of the overflow water which is 5.5' higher than the sump base. The 40 inch drop from the pump to the spray injection nozzle provides approx 1.5 PSI of additional pressure. The MAG 5 generates around 4.6 PSI so I get around 7 PSI in theory.
To keep the skimmer pump from running dry and to keep constant pressure on the injector, I route the extra water through 2 traditional durso topped stand pipes. Since the MAG 12 is pushing significantly more water than the MAG 5 does, the water level in the overflow stays at the durso inlet height. This keeps the MAG 5 completely enveloped with water so it doesn't run dry and keeps it under constant pressure. I am planning to add a float switch to this compartment to ensure the MAG5 shuts off if the water level drops too low.
The refugium is handling more flow than is conventionally suggested, but my nitrates have remained at 0PPM for the last 4 months and my chaetomorpha macro-algae doesn't seem to stop growing. The refugium is full of visible amphipods, bristle worms, fan worms and such.