I wish I knew. I researched my problem for hours upon hours that night. Frustrated after finding nothing, I went back to my set up to tinker around with it. I did all of the same things I had done before, pushed the connective LED clips together harder, verified all the wires were in correct placement, etc. and then I plugged it in again and it worked... I was just happy that it worked and didn't investigate further. I disassembled it (It was on my dining room table), carried it in parts down to my my tank in the basement and assembled again, and it still works perfectly... So I really can't answer what was wrong!