I've been constructing a grow room in a decent sized closet and have just recently measured its humidity to be around 35-40% -- far too low for the veg phase. I'm thinking of installing a powered humidifier to raise humidity; however, I am concerned about the closet's airflow negating the effect of the humidifier. I'm using a 424 CFM fan for exhaust, which generates an upward wind speed of about 8 in/sec, replacing all the air in the closet every 10 seconds. (I've calculated this rate of exhaust to be necessary for cooling of the closet, which will contain a 400 Watt lamp.) Is this something I should be concerned about? What's the best way for me to raise the humidity without jeopardizing my temps?