From the tanks i view so far, one of the best systems belong to this reefer who have a 4ft tank but a 6 ft cabinet. As a result, he's able to have a huge sump. His sump is built in such a way that there's a 3x1.5x2 ft sump join to a 2x2x2 ft refugim. This allows him to have the space for his equipments, as well as a refugim for macroalgae and copepods to grow.