I think he is saying that he has an incandescent fixture and will be adding two of the screw in compact 50/50 bulbs.

I don't know the exact wattage on the bulbs, but I'm thinking around 9-10 watts. I doubt you will be able to keep really anything except maybe some mushrooms, even if that.

I would invest in some kind of retrofit lighting from www.ahsupply.com if you really plan on having corals.