They are being transitioned from 24/0 to 12/12 one hour a day. Currently at 18/6 and holding there until conditions improve. They spent last week at 90F and didn't get much fresh air. I'll take your advise on keeping them under 80F. I don't know what you mean when you ask for newt temp. The light, 400 watt hps, stays about 14-16 inches away from the tops and that's where I get my temperature reading from. About 300 cfm ventilation. whenever the light is on there is a recipricating from that takes a suction from the vent port on the tent. Climate is about 30-40% humidity. Thanks for your help