How much light energy would you say a cool tube absorbs? And if you don't mind any suggestions on their use.
I remember reading somewhere that 85%-90% shines thru...So I guess 10%-15%. That is just off the top of my head but I remember seeing that figure when I was searching for cooltubes. I used the Pyrex baking tube for my cooltube. Luckily I dont need it anymore but it worked very well on my 400w. I was using a cab so I took one end of 4'' duct and ran that to the outside for intake then used the other end of the duct and put a 4'' inline booster fan in it sucking air out. It was pretty effective.