I can tell you you don't need the magnetic drive one at 105 watts, That is more designed for multiple aquariums, Just curious how much that one that is 55 watts run, I think you can get a pondmaster AP-20 which should run anything you might need for about $110 shipped. It will use a little less watts than the one I have and should be still more output than you actually need, Although I don't know what your planning on using it for. My AP-40 runs three air stones 4" round (2 of these sit in 2' of water the other 3' of water), one standard air stone for the sponge filter. and I still bleed off a pretty good amount of air that isn't needed.