IMHO, the total gallons/hour isn't going to help you much. It's the placement of the flow that's really important. In the system below, I had a haddoni (low flow anemone) and a gigantea (high flow anemone) and was able to create localized environments to keep them both happy.
This is in a 40 breeder. There's a mag 9.5 return, and a mag 9.5 on a closed loop pushing through a SCWD.
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