As far as flow rates are concerned, my 2213 runs at 116ggh, and it is plumbed separately from the sump/refugium. So, the flow rate for the canister is approximately 2x per hour on the main tank. I want that to be fairly slow, so that the water has time to come in contact with the bacteria in the canister.
The flow rate from main tank to the sump/refug is about 500gph, or about 8x per hour for the main tank. I aim for a turnover rate of 6-10x on the main tank through the sump/refug. I feel that moving the water faster than 10x gives you no benefit whatsoever from the setup, and moving it slower than 6x is too slow to get the oxygenation and replinishment effect to the main tank.
My skimmer is in my sump/refug and is running off of a OR 2700 which pumps around 700 gph. So, I throttle my tank pump back just a bit, so that I am sure to get water that has been skimmed pumped back into the tank. I do actually have all this worked out on paper, for anyone that would like to see it.
