Any of the Mag pumps will work. I use a mag 18 to drain. Takes literally minutes. Find a used Mag pump on one of the fish forums or EBay.
Mag 18 to use just to drain the tank ?
Quite an expensive way to go. Just get any cheap submersible pump. Does not even have to be that powerful. I use a no-name pond pump rated @ 300gph to drain and pump the water back.