Don't do what I did and buy your sump first only to find out that the skimmer I really wanted would not fit in the sump. IMO your budget is going to limit which skimmer you willl purchase. For the budget minded, ASM, Vertex, Precision Marine (red line series), and EShopps, are a few viable options, all are needle wheel designed and driven, and and first several have all had reported problems with their associated pumps. I just purchased the Precision Marine Redline 125 for my FOWL 120 to replace a reef octopus reciruclation skimmer due to it's very small footprint. I guess I should also asked if you skimmer is going to be H.O.T. or in sump.