Looking at your layout more carefully, there are two things I would change slightly:
- the leftmost baffle (the one between skimmer and refugium) should be higher than the first one on the right side... because when your sump fills up due to a power outage, you don't want the stuff in the fuge to flow back into the skimmer compartment. If you have that baffle set at say 8" due to skimmer constrainst, then lower the baffles on the right hand side...
- I found that having a fourth baffle on the right hand side helps a lot with the bubbles... with only 3 baffles, the last step will be a "waterfall", which may cause some bubbles of its own... on the other hand, if the last (rightmost) baffle is raised, the water will flow under it, the bubbles will be contained behind that last baffle and no waterfall will happen
Also, if you're planning on running carbon in a bag placed between the baffles, make the spacing between two of them around 2", to be able to accomodate a bag easily (I have 1" spacing and it's very tight).
Nuno