you got it.
Tank is coming along nicely, looks good down there, and glad to see you decided against stingrays, I think that will be for the best.
Since you've got CO2 this fixture would work great
http://www.catalinaaquarium.com/product_info.php?cPath=71_7_68&products_id=1356
The 125W power compact fixture would probably work, the bulbs are only 41 inches though, and the T5s would be a lot brighter.
Even 2x80W would work, the whole tank would be lit and I don't think the light output would be a whole lot less.