A few reasons. Your intake should be at the bottom because heat rises and if your intake is at the bottom your intake temp will be lower, the root zone of your plant will thank you for the lower temperature. if your intake is at the bottom and the vent is up top you will refresh the air inside your grow more efficiently.Oh okay is there a reason to why on the bottom
You'll also be drawing the fresh cool air through the canopy to the topOh okay is there a reason to why on the bottom