well, i started overlaying charts, and noticed that the dishwasher we started right before going to bed had hit its drying cycle during the spike, but the dishwasher is on a different floor than the co2 spike. the co2 spike was downstairs, but the dishwasher is upstairs.
well, co2 is heavier than o2..
but notice the two non-spiked lines. one is the bedroom, the other is my indoor fruiting tent.
with the whole house fan running, theres no surprise that the bedroom had fresh air