Too much fluorescent light?

[DTEguy]

I have a T5HO setup and I try to give my orchids as much light as possible--but I do understand light duration can affect blooming for orchids.

There are a couple of questions which I was wondering and would like to discuss with some veterans here (some are stupid questions ):

1) What actually "burns" an orchid? Is it UV and heat? or some sort of photo-stress? If it's UV and heat, does that mean fluorescent light (if not touching orchids or in high heat) don't really burn orchids?

2) Is there a photo-stress in general for too much light? (aside from UV and heat stress)

3) Subtle purple pigmentation (expression of anthocyanin) has been a good indicator for some orchids that they have received optimum light. I have also read that growing orchids to the point that they are very purple is desirable and actually blooms orchid better.

Is there a concern of too much anthocyanin on leaves?

Moderator: Please feel free to move my thread if I should discuss this somewhere else.

Thanks!