What trido said about running the 'fug lights opposite of the main, except that it really doesn't do any good to run lights 24/7. Most things stop photosythesizing after about 13 hrs and grow in the dark (night) period. All you do when you run the lights 24/7 is waste money in electricity and reduced bulb life . A cheapo appliance timer set to be opposite of the main tank is an easy way to handle it.