radon manometer reading 4

https://myradonfaninstallationhaven.swiftnestly.com/posts/what-to-expect-during-a-radon-fan-installation

The radon manometer reading flickered uncertainly, settling near the threshold that always makes me pause. I tapped the glass twice—old habit—and noted the slight rise from last month. Not alarming yet, but enough that I’ll ventilate the basement before the kids sleep down there.