Im not sure what part of the tunze ato you messed up, the actual power supply that plugs into the wall or the brain (the part with the float switch hooked up to it).
I currently a custom ato with my apex, I use the tunze ato pumps instead of the common aqualifter pumps. I power the tunze pump with a old 5vdc cell phone charger I had laying around. The pump is rated for 11vdc, but I found since I dont have alot of head pressure on the pump it doesnt require full voltage to get the job done.