it works well for me with 11 feet distance. I run it at 100% and the water on top of the tank from other side is very turbulent. It gave me much needed flow in the back where i could move mp60s to other locations.
Having 8 foot tank, you can probably dial it down to 50%-75% and it would work just fine.
But if you have sand, it maybe too much flow
Thanks for the feedback. I have no sand as I’m bare bottom.