Right now I've got 2 Tunze 6055's and a Tunze 6105 which max out to around 6300 gph combined. Since they are on controllers and the flow pulses up and down, maybe I'm getting around 4,000 gph at any one time. Plus maybe 300 gph from my return (Tunze Silence). So overall maybe 43x turnover.
How is your tank going. Mine has never taken off. I am breaking it down this weekend and letting it dry out for a month and replacing the foam reef with all new live rock. My corals are in a friends tank in the short term. Take care!