Trouble With Heat

I have a 1000w MH in a 5x7x9 room with co2. Just put it in there 2 weeks ago today. I started 8 bling plants to flower which are all about 2-2 1/2 feet tall. I can ventilate the room no problem when I am home but when I leave I lock it up sealed. I have a big fan blowing over the tops of the girls but some are starting to wilt a little. Any tips?? Would a dehumidifier do the trick. Also the light is about 3 ft above the tops.

Maybe they need water. As the plants grow their intake of water will rise. I always use drooping leaves as an indicator they need feeding. Also bring the light down to about 18" or 15". A good indicator is to place your hands over the tops of your plants. if it is uncomfortable then the light is too low.

That's a 1Kw MH, and they put out more heat than a HPS, and should be hung at least 2 feet above the plants. You will have to exhaust the hot air. The CO2 will allow you to provide less fresh air, but they still need some. In hotter rooms they will use more water, and require more of everything as they get bigger.