Tim,
My tank is 84"x24"x 24", and is moving about 750 total GPH through two return lines, chiller, uv, in-line therm., 30 gal sump. I have soft and LPS corals, with about 300 lbs of live rock, and a heavier fish load.
I really need more movement in the tank. In the past I've used jets for flow, but they are a real pain.
I'm thisclose to ordering two vortech's for my tank. I'm not concerned about buying the "older" model, with the coming upgrade.
Anything you can add, please do so. BTW i'm partial to lehigh folks since my husband, and 2 bro's went there.