Rbarb111, You will need a reflector comes with most kits or get one cheap bit of reflectoring material from a machine shop. that will help spread the heat then you can leave some of the top open for venting. When I biult my top to my tank I framed it on three sides and used a strip of ply wood to attach the retro kit to it reflector then mongal base so when you look at it you dont know that the top is open there was a 250w bulb it did nit scorch the wood but it was a little to close to the NO floresent that it got scorched but no damage