Six plants With one 400w light.. Probably not enough in my personal opinion, but they will still grow. Yields won't be very impressive. Also why would you blow air into the carbon filter? The filter and fan is used for moving a specific CFM of air out of the room any use otherwise just doesn't make sense for what you payed for also not to mention you want constant movement of air out of the room. I would recommend using a different tube of ducting for your cooltube with a fan, most likely 6 inch...