My aquacontroller III can't turn an aqualifter pump back off for use with my ATO. It was driving me crazy trying to figure out why it wasn't working and I figured it was the switch. However when I tested with a light it worked just fine. Basically it will turn the aqualifter on but then I can't even manually turn it back off. Any ideas why that is (maybe not enough draw) or what pump I should use instead?