When I first saw your post my thought was why didn't I go with that design as it seems more simple than mine.
I just realized that with your design you will have a lot of flow running through your fuge unless you are running a smaller pump and a seperate closed loop or PH
for additional flow in the main.
Before you start to build take a look at this thread:
Within the thread is the link to the design I followed and some others ideas. With my sump there is a bit more plumbing, but it is very simple. I view my fuge as a final stage for polishing the water as well as a place to increase pods
. I do not run a closed loop either and mine have been working great so far.
Just a thought while you are still in the design stage.