as gaines said, it will block a minimal amount of light, but not much more than any commercial one.

but by having the tube, your bulb can get much closer to the canopy, which provides more intensive light to the leaves.
hybridlove420 Reviewed by hybridlove420 on . Homeade Cool tube=loss of plant light? I hear the bread bakers(and cyclone tubes) that you can convert into a cool tube.... Grow Marijuana FAQ, Cannabis cultivation - marijuana growing tips & photos ..are a great way too cool hot HPS bulbs. but does it take away lumen's or usable plant light due to the glass in the way? :rastasmoke: Rating: 5