I agree. With my control, I can clearly see when there are too many "breathers" in the house producing excess C02 - like wen we have a gathering or a party. For instance, if we have people show up around 5pm, PH can go from 8.1 to as low as 7.9 (or lower) in a matter of an hour. So far I have not experienced any ill effects when it happens, but the first few times I observed it, it freaked me out. In contrast, in the cooler months (sub 79 deg :-/) I can see it rise pretty quickly when I open a window.