Last summer I used a 400w hps uncooled in 36"x16"x66". Temps stayed in the high 80s to low 90s usually with the light on. I switched to cmh but that didn't help with the temps at all. Plants grew but they didn't turn out great and didn't get a very big yield. Ill try again this year when it gets...
i saw that pic. i also use a phillips 400w cmh and id burn my fingers if i touched it like that after it warms up
its even warm after i let it sit and cool down for 10 minutes to switch bulbs