wow i wasnt gonna post in this thread, but because jack47 was such a dick i figured ill try bring the IQ of this thread up...
I dont believe is that whole only the last two weeks BS. think about it, your using uvb lights to increase trichrome production. so you believe that trics are the plants natural response to protect itself from uvb rays.
well if i was doing that shit id want them on through out its whole flower period, maybe not the first two weeks of 12/12 cos thats a transition period, and maybe not the next two because they are adapting to alot but after that id run it, not if you wanna not run it for the full 12 hours, you could run it for 4 hours at midday, so 4 hours of lights on uvb light off, 4 hours of lights on uvb light on, 4 hours of lights on uvb light off.
about the 10% spectral lighting, i havent a clue where the scientific data backs up that claim, id but them all in.
I WILL WARM YOU.
uvb is harmful that we do know, so dont enter your room with your uvb light on, put it on a switch you can turn on/off yourself, or avoid your grow room while its on.
peace, and dont let idiots like that effect your day