I ran into the same problem with my 46 bowfront. Instead of trying to put one under the tank, I went with the Large CPR Aquafuge. Surprisingly, it does an awesome job. I've got a fairly deep sand bed in the fuge with lots of Macro Algae and a few pieces of rubble rock. In the 46, I've got about 60-70 pounds of live rock. I've got a Mandarin in this tank and TONS of pods and Mysid Shrimp. At any given time, I can look in the Aquafuge and see lots of pods and shrimp.