Just send me a message and I would be happy to help you get X10 setup. It is really easy, however, there are a few things that could cause it not to work. You electrical system, if you ever look inside your electrical panel, is made up of 2 different phases. You electrical system is 220 coming into your house, but it is split into 2 phases of 110 each. It is possible that you have your transmitter plugged into one phase and your receiver plugged into another. You can either just make sure that the plugs for the transmitter and reciever are both plugged into the same phase or you can buy something called a phase coupler (which transmits your signal across both phases). If you are interested in doing more with X10 than just turning on your aquarium lights, then the phase coupler would be more than worth it, otherwise, it might just be easier to make sure both the transmitter and reciever are on the same phase ( or move it one so they are both on the same phase).
Glen in Atlanta