Also started the pot air injection pump and tent humidifier today. Shooting for 60%RH zone. Just got the little humidifier. It is only about 6 inchs square and it uses a 20 oz plastic bottle for a reservoir. Seems perfect for my tent and is working great. The destructions say to only use 20 oz size, but I'm going to try using a 2 liter bottle. I am sure it will work but will be top heavy and easily upset. I think by pushing it into corner of my tent it will work fine with 2 liter bottle.