Hey MoF, here's a link to a retrofit fixture that works with your regular hood, if you have one that is. It changes from a single T8 to a dual T5 with LED moonlights. Check your measurements to be sure of course. It also appears it has a sep. switch for each bulb but the moonlights stay on, that's annoying.............but still a lot less expensive than some of the Coralife & Current fixtures available.
Dual T5 with LED monnlights:
http
/www.amazon.com/Deep-Blue-Solarmax-Double-Strip/dp/B003I5VQ02/ref=sr_1_1?s=pet-supplies&ie=UTF8&qid=1349016309&sr=1-1&keywords=solarmax+30in
Single T5 without LED's:
http
/www.amazon.com/Deep-Blue-Solarmax-Light-Strip/dp/B003I5UC84/ref=sr_1_3?s=pet-supplies&ie=UTF8&qid=1349016309&sr=1-3&keywords=solarmax+30in
You may want to go with the single T5 if you want your tank to remain low light.