It also kind of depends on how your tank will be plumbed. For the Tunze you don't need any drain or return lines. For the Sea Swirl, you will need a return line from either your sump or closed loop to feed it. If it's from your drain line/sump, then that is not really adding extra current, it is simply giving some change in wave/flow action from what existing flow you have from your return pump. If it's going to be fed by a closed loop, then that means more holes drilled in your tank, more plumbing, another pump, etc. Also, the gph is restricted depending on the size of the Sea Swirl. I have used Sea Swirls on a few tanks and love them, but they are big/bulky and you have to account for them in your plumbing plan.