what do you think the max co2 ambient level 'could be 'just with a door/window open /closed ......without a co2 add.....non sealed room....
plenty of flow.....w/exhaust fan suckin it thru....?
w/circ fan also.......
basement w/grow room within it....good clean fresh mountain air......guess i really need some type of metering $........to really know eggs ackley