My problem is humidity. I am consistently running around 30% in the vegetative stage, which is about 35% below where I want to be. I can see signs of humidity stress on the leaves. I even bought a nice humidifier today that runs for 24 hours and it managed to raise the humidity levels in my 4x4x7 tent by 1 percentile.
I have a 4 x 4 x 7ft grow tent indoors. All the air vent have been duct-taped off for an air-tighter seal. I run a Sunblaze T5 4'x8 lamp fluorescent fixture in vegetative, and a 600w HPS (6" air-cooled SunSystems Blazer reflector) during flower.
Currently, temperature is not an issue. I pull in cold winter air for my intake. My intake fan runs at 160cfm. It might run a bit slower, because it's a duct booster fan that I have put a small screen on the intake side to keep dust and bugs out. It runs for 24 hours.
My exhaust fan is a 190cfm inline model with a 4"x12" carbon filter attached to it. I'm assuming it doesn't really pull out 190cfm. The fan is manufactured by MTN Gearsmith. It runs for 24 hours.
What gives? Is there a timer that I can hook up both my intake and exhaust to, that will turn them on for 1 minute, every 5 minutes? Is that even the cause of the low humidity? Or are there other factors I'm not considering.