Quick input needed

The Blowhole 1450 at the lowest setting will push 591 gph @ 6' of head. If you're plumbing off the main return you will probably only be pushing about that or less into the main tank - a little low. I'd start at the middle setting, put a ball valve on the output and play with the output using that. You want as much flow going through the sump as realistically possible (if I can get 10x tank volume I do it).

Other comments:

- Since you're feeding the fuge section separately, you can keep the height at 12.5" as you've planned to give you more fuge volume.

- All you need to do is lower the third baffle from the left to 9.5" to keep the skimmer section depth as desired.

- I'm going to make a very bold suggestion on your build thread page that, if it's possible given your home footprint, will give you an amazing set up.