Glass will block the energy from the light too(ever wonder why you can't get a suntan in a car?)

as for the colour change? i'm not sure.. again it could be completely normal... the leaves on my one plant are starting to go a dark green almost purple colour..

maybe if you post a pic?
BobBong Reviewed by BobBong on . Plant's Night Time Droop. what is it? hi there, so i take this as a trait or the attitude of my plant. but i know that is just a joke, but every day, when the light comes on, my plants are nice and perky after a good nights 6 hour sleep. then about 2 hours before lights go out at night, the larger leaves primarily start to droop. they really don't look bad, they just droop. the next day they are back up again. what is this? my PH is good, the rez temp is good, is this a nutes thing? my 400W HPS light is 20 inches from the Rating: 5