There is a hood on the tank currently, but the previous owner cut out the top for the halide fixture to fit into. The fixture currently has legs that rest on the inner edge of the hood and sticks out the top. If I were to retrofit the T5s then I would probably fill the hole so that the whole deal could hinge open again like it was designed to do. Fans would need to be added to the hood though for proper ventilation.
I think I may have talked myself into keeping the tank. The wife only asked, "how much will it cost me?" I told her, "practically nothing once I sell the halide fixture and ballasts to offset the cost of new T5 bulbs and endcaps."
It's a free upgrade.....sort of.