Although co2 (MolWt 48) is heavier than air (MolWt ~ 30), that doen'sn imply that it will sink to the bottom. Oxygen in our air is lighter (MolWt = 32) doesn't sink to lower levels and leave lighter nitrogen (MolWt = 28) higher up. That's because gases mix themselves. Measure co2 anyplace in the tent if the air is well circulated. Or measure top and bottom, then average. Bear in mind that if your tent is vented, co2 does little good.
im in a sealed room and thank you for the info! i currently measure it just a few feet off the ground
