The more I read into this, I'm finding that, you girls only accept UVb until trichs start going amber. possibly that UVb is what causes ambering of trichs. I'm reading that HID bulbs put off some UVb as well. MH more so than HPS.
This is all conjecture so see what ya'll can find. Since glass filters UVb, I've taken my glass off my HPS. Anybody think this could be a mistake?