Okay so you did a better job at explaning it than me.The pictures have me a little confused.. lol. It looks like the sumps are being drained from the center reeflo pump, but you say there are internal pumps in those sumps now? The internal pumps drain the sumps straight back up to one of the return nozzles on each side? And the reeflo is also draining both sumps, tees off and then is feeding all the canister filters and being returned to the other return nozzles?
Yes, the internal have there own pumps to return water back to the tank through a set of returns, and also there is water being used by the Dart from the sump, to feed the canister, then returned to the other two returns in the over flows. This worked out well because the overflow drains, are flowing a great deal of water.