Blueprint Controllers CO2 Generator NG 2-burnerThe Blueprint CO2 Generator For those who have a natural gas hook up, the CGNG 2 model is for you. It features 2 burners that generate 5. 4 cu ft hr of CO2. If you are using a propane tank or a propane source, get the CGLP 2 model. This also features 2 brass burners and can generate up to 5. 3 cu ft hr of CO2. If you have a smaller grow room, you are in luck. The second burner on each of these models is removable which will cut down on CO2 output as