70w HPS bulb. how close can it be?

hey,

i have a 70w HPS for one plant. it will be a pc stealth grow, pc case is 26 1/2 inches.
i wanted to know how close can this bulb be to the top of the canopy and be safe?

~ thanks

u might want to stick with cfl's with a pc case with heat issues. ive got a 150w in a 2x2x4 box and temps get high, 100 for a few hours during a hot day, but i keep it about 8 inches away and they seem to be fine, put ur hand under the bulb and if its to hot for u its to hot for them

if there is any way u can detach it from the ballast and the mogul build a cooltube go to your local hobby store and get a hurricane lamp glass and then go get a 50 cfm bathroom exhaust from lowes or homedepot. then get a 3 inch ducting and attach the ducting to the exhaust fix the mogul inside the glass u can get a plastic connector piece and then screw holes and get till it stays in place then put the glass over it and attach a clamp and plug in the fan and wallah u got a cooltube can be 3 to 4o inches away bro