how many times a hour should the water go through the sump?

[banditpowdercoat]

One way you get close to a FIFO style sump is with a recirc style skimmer. If the drain of the tank is fed Directly into skimmer, then the skimmer will skim 100% of the sump flow.(to the skimmers efficiency's of course) The Sump return pump would then only need to be sized for the skimmers need. But, it seem's most skimmers now are being made single pass.