Sump Refugium

[lodidodi]

Wondering if I can pick the brains of everyone on this board about the sump/refugium I'm planning.

I'm planning out the sump/refugium that I want to put under my 90 gallon tank (48" x 18"). I think I'm going to go with a 33 gallon long (48" x 12" x 12"). I'm thinking this would allow me 4 sections of 12 x 12. The first would hold the skimmer, heater, etc. I was thinking of putting a DSB in the second section, macro algae (either ulva or chaeto) in the third section. Then the return pump in the fourth.

Does the layout make sense? Is there a better set up for the sump/refugium?