Recirculating skimmers are suppose to be set to have a flow threw them of 1 1/2 to 2 x the tank volume. This skimmer I have is best at 200 -300 gallons flowing threw it. My new tank will be 180g not 225g, I just dont have enough room for that extra 6" space.
I have read its best to have a overflow feeding the skimmer and only the skimmer not split to the sump, too hard to control a steady flow threw the skimmer. So this middle overflow would have a ball valve on it set to maintain about 250g/hour, the other two overflows are the main overflows.