I have a rectangular tent that I'm planning to use as a mushroom fruiting chamber. It measures approximately 120 x 60 x 150 cm and has two duct fans installed--an intake fan near the top of the left side and an exhaust fan near the bottom of the right side. (Both fans are the same size and type.) I placed a cool air humidifier at the bottom left of the tent and was expecting the water vapor to flow towards the exhaust fan. Instead, it moves in the opposite direction--towards the intake fan and seemingly against the direction of air flow. This happens even when the exhaust fan is on the highest power setting and the intake fan is on the lowest setting. Only when I turn the intake fan off entirely does the vapor from the humidifier start moving in the direction of the exhaust fan.
What could be the explanation for this? Does it have something to do with the fact that water vapor is less dense than dry air and therefore travels toward the intake fan where the pressure is higher? (Appologies for the crude diagram).