The 199g sump is the biggest sump I've constructed thus far. Water enters the rear left corner, flows to the right, then to the front and finally back to the left end where the return zone exits to an external pump. This raceway method prevents microbubbles, although with a 14' travel time there shouldn't be any. The equipment sits on acrylic shelving to keep it clean. The refugium zone allows for a DSB, and the live rock zone in the front can be used for additional natural filtration.