This thread taken from a post I had made earlier, T-5 lighting maybe overkill for your tank if you don't plan on growing plants though. Other wise you might try different bulb spectrums with your current light system as you probably have just plain bulbs.
Anyone out there- especially Canadians wanting to upgrade their lighting, I would check out Catalina Lighting in the U.S.A. They will install the bulbs of your choice, and can customize your size of light to include the dimmable moonlights. I searched locally in town for something comparable first and it would have cost me between $600-$1000 for a 2 - 4 lamp T-5 system with moonlights- that were not even dimmable. My light from Catalina only cost $250.00 shipped to my door. Things are so much cheaper in the U.S. and we Canadians are getting hosed!