The Model S sump is a simple design that will fit under smaller aquariums. With two zones, it is designed to hold the Protein Skimmer and heaters on one side, and the return pump and a small hang-on reactor in the other zone.

20" x 14" x 14"
Skimmer zone water depth is 7"

The rimless design is helpful when working in a smaller sump, but some salt-creep may be experienced.