Do you have a sump attached? If not the TurboFlotor Multi or Sapphirewould probably be top on my list. If yes, then I would cram the biggest Octopus I could into the sump or try a DAS/Deltec if I had the money. BTW, the midflotor can hold its own against a variety of skimmers costing many times more. You just have to keep the airstones fresh.
Also, the guys at Petland Alph use a Nano Fission on their cube and it seems to work well.