This is what I have managed to learn. In a typical grow room, you want the temps to never go below 60 degrees F and never above 80, but when using CO2, all bets are off. I've been told an increase of at least 10 degrees is needed, bringing a grow room that is 70-75 degrees to 80-85 degrees. The reason is the plants need the extra temp to help process the co2. Think dinosaurs and stuff. When the earth was younger, there was more heat and co2 in the air, and that made ferns grow to gargantuan sizes, among other plants.. Im no dinosaur scientist guy, but I've seen Jurassic Park, and I know that heat plus co2 means gigantic plants... Also, the ambient level of co2 is going to be about 300-350 in the room, you will want to raise it to 1000-1500 PPM (parts per million), anything more is pretty much a waste of co2. This is accomplished by placing a regulator on the tank with a timer that sprays every so often, once an hour or so. So, temp increase is about 10 degrees, up to 85 degrees F, and the lowest is 60 degrees, no lower... Hope it helps..