How do you regulate air temperature in a grow tent? Do you run the fans on timers or are the fans on all the time or do you use a thermostat control. Some of the fans I've been looking at are less expensive but do not have a way to regulate the speed or on/off switch. I've seen one fan that has thermostat control on it but little pricey but I'm not sure if it's really needed. Right now, I'm considering a grow tent 7'x7'x7' because I may move within the year but may build my own. I will probably start with 600w HPS light and get another one if needed.