You don't need three, The Power Adjust is the same as a fan header on the Aquaero 5 XT , Pro, or LT when it is connected to the aqua bus High side header on the Aquaero also called aqua bus #2. It can handle more amps so you can control a pump or a large fan with it. When connected to the Aquaero via the aqua bus High Side header it will show up as fan 5 you can change this to Pump in the Aquaero menu. If you need to power more high amp accessories then you add more Power Adjusts.