I would have to think so.... Unless it was like 2-3 feet above the tank, lol. I found this while I was looking: http://www.nano-reef.com/forums/lofiversion/index.php/t192007.html
Pretty much agrees with me, lol. A 75 watt would be good, still might need some fans though.
It might be! You would have a look of light spillage and heat transfer. Although if you could hang it high enough and supply good ventlation then you could see how it works. No need to rush out and buy new equipment if you already have extra in your coollection! LOL
i have a 70 watt mh retrofit that i had on a 12 gallon for a few years, ballast and de socket are still good if you are interested i will sell it for $40 or trade for whatever i might need.