Minimum flow through sump?

[sonofgaladriel]

What would you all consider the absolute minimum amount of flow one would want to push through the sump and still have it be affective for bringing water to the skimmer, reactors, and such?
I'm planning my 72x72x30 and want to have as minimal viewable plumbing as possible and am considering just one off set small overflow. I was thinking that on a 674 gallon tank, 3200 gph (about 5 times turnover) would be enough flow through the sump. An additional 9000 gph or so, via a closed loop all plumbed through the bottom or via Tunze.
Can I push less than 5 times turnover through the sump and still have it be affective for filtration purposes?

 

[Kent E]

I'm running 600 gph on a 450 gallon tank. I was worried at first but it seems to work well and the heat isn't a problem either. Apparently, we don't need as much as some say. Its a BB system by the way.

 

[Fiziksgeek]

What king of skimmer are you going to run?? WHat about matching the flow through the sump to the flow through the skimmer...?