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

[MikeInToronto]

I'll use an example. Let's say you have a tank full of sea anemones. We'll make them ritteri anemones because they like lots of water flow. In this tank you don't want a PH, closed loop, or anything with an intake. The OF is fine because it is easy to safeguard an overflow without losing efficiency. How do you get the flow up to, say, 10x flow without using PH or CL?