I'm doing a small talk on growing orchids in terrariums at the St. Paul Winter Carnival Orchid Show (if you're in Minnesota you should come to it (Jan. 28-29)at Marjorie McNeely Conservatory) and am seeking some help regarding light information. Unless I'm completely wrong, I recall hearing somewhere that for every "normal" pane of glass sunlight passes through, a certain percentage is reflected off and it decreases the intensity. I was hoping to use that as a justification/explanation to why you need supplemental lighting even when a terrarium is near a window. That way you get the best plant growth. This is what happened to me; my Nepenthes stopped pitchering once I brought it inside until I got some supplemental lighting. Anyway, I didn't feel comfortable using information that hadn't been substantiated by another source. If anyone else has heard of this "fact" and knows the actual percentage/amount of light that gets reflected I would be very appreciative. Thanks in advance!