I'd say you want total turnover of about 8-9 times an hour, but that includes power heads creating movement as well as the power of the filters. My goal is to have minimal dead areas, a few high flow areas, and the rest somewhere in between. With larger tanks, this is easier to accomplish, since you have more room to play with.
But--as long as the parameters are in the green and the fish are happy, you should be fine.