video update and a question! help

hey again, made a new vid a couple days ago. and last night added a 400w to the other side where the aerogarden was. ill take a new vid tonight. but in the meantime watch this. oh and the QUESTION is , by adding tempered glass to the reflector hood (20''x20'') am i losing lumens ? it does keep heat back a little but i want to know what am i losing by doing this?

Video of mar11 08 - Photobucket - Video and Image Hosting

You will certainly loose lumens. But the Question is "will the reduction in temperature make up for the loss of lumens?"
If the lamp is running cooler you can put it closer to the plants, thus increasing yield.
If light passes through the glass it will reflect a few lumens, thus decreasing yield.
Not sure of exact figures.