I don't have glass on my 400w HPS but I have great circulation and ventilation and my 2nd round under that is going great with no problems, I have a fan blowing directly across the bulb as when as circulation and ventilation.

No problems here though.
sd6515 Reviewed by sd6515 on . UVB BULBS anyone use em currently? im thinking about it but would like to know if they are any good. and also what kinda temp does it (they) put out Rating: 5