I used screen from HD, the uhhhhhhhhhhhh fiberglass kind. I tripled the layers. What kind of bulb is in there, what is it's Kelvin rating and what ballast is running it? I can check Sanjay's site to give you better info. Edit: Oh well, if you are running PCs you probably wont have to acclimate. 15" is way too far away. Mine are about 8" off the water