how many times a hour should the water go through the sump?

[danny zubot]

These theories are all based on the idea that your sump is a filter. While it may seam that most of the water cleaning devices people use are situated in the sump, this doesn't make the sump a filter. It's a place to house filtration equipment. I view my tank, my sump, my refugium and all of the plumbing in between as 1 body of water. So to me it doesn't matter how much flow goes through my sump because my skimmer would work the same down there as it would hanging off the side of my tank, or in my refugium.

As Levi said, the skimmer works at a set rate so it shouldn't matter how much flow is churning around it.