I am working on designing my first sump and want feedback. The space I have to work with a closet under the stairs. The space for the sump is about 36" x 36" x 48", accessed through a 20' wide door. Nothing can have a diagonal greater than 36" if it is to be turned once in the closet. I am thinking I will utilize 2 20g Longs and 2 10g tanks. Here is the 3D models I created.

sump1 - Sump design- feedback wanted
sump2 - Sump design- feedback wanted
sump3 - Sump design- feedback wanted

Water from the DT flows into the right side of the middle tier by the skimmer, where it goes through a bubble trap to the pump section. The pump section has a large pump that returns water to the DT and a small pump that sends water up to the top tier for the fuge. The fuge flows to a DSB, and then back into the skimmer section. The two 10g tanks at the bottom act as extra overflow room in case something goes wrong, and a top off holding tank.

Feedback welcomed!