Do you have any ventilation for that box?? Do you know what kind of temps you have inside there?...and the Aluminum foil isn't a good idea, you can create hotspot's and fry those little guys even with CFL's. You have a lotta Lumens on those little guy's, maybe unscrew a few of those lamps for now too.
You might want to buy a cheap "space blanket" and use that as a reflector. Maybe a CPU fan for the box as well.
Just my .02