I was just asking questions about how lighting is on freshwater tanks on another thread,... I'm not sure if your using saltwater or fresh but on my saltwater tank I was useing a Satellite 24 hour lighting system. The reason for the "24" hour part is it comes built with Lunar LED
's on it. Basically you turn off the main lighting and the moonlight stays on overnight. It works great with saltwater... but in my other thread I've been asking about them in fresh. The moonlight does look awesome at night. The tank I'm asking about now is also a 20g.