Certainly nothing too big IMO. Especially if you are doing drip. I think 200-300 GPH should be plenty. If you are pumping over long distance or a lot of vertical height, you may want to step it up a little. FWIW, I think all of the ecoplus pumps have threaded intakes. I know my 396 GPH ones do. My active aqua pumps at that size do not. Its nice to have if you want to run them inline in the future or throw a PVC elbow on them.