Hello, I have a new mylar grow tent that I am working on. This tent is for VEG only with light on 18/6 schedule. Length 3ft x Width 3ft x Height 6 ft. Thats 9 square feet with 54 cubic feet. I have a 400 W MH Bulb that gets quite hot in this mylar enclosed space drying up some moisture. Right now I have a 170 CFM bathroom fan as an outtake on the top with 2 passive intakes at the bottom of the tent. The 2 passive intake holes have light traps and are about 6" each. This creates a negative pressure inside the tent once its all zipped up. The room is exchanging about 3 times per minute. This gets my temperatures down to about 80 degrees F with an oscilating fan when the light is on. The humidity however is a mere 20% tops. I feel that the outtake fan is sucking all the moisture out of the tent and bringing in the ambient humidity which is only about 20% this time of year. I added a humidifier to both the tent and the ambient room and still 20-25% humidity tops. When the light and outtake fan is off at night the temperature gets to about 72-75 degrees F and 60-70% humidity which IMO is perfect! As soon as the light and outtake fan are on BAM humidity goes down to 20% and temperature to 80-82 degrees F. Is 20% humidity for VEG OK ??? Is the drastic humidity change a major stress to the plant? 20% day and 70% night humidity? I use Domes for seedling/clones so thats not a problem. My mother plant might not like the 20% humidity though... Trying to tweak as best as I can. I fix the temperature issue but at the humidity's expense. Please help!