Here are a few excuses for sudden drop in Chlorine levels that I have heard in the last couple of years. I am curious if anyone else has heard of these.

1: Gases from the septic tank have drifted over the pool and robbed you of all of your chlorine.

2: A farmer was applying anhydrous ammonia to a nearby corn field and some drifted over your pool and robbed you of all of your chlorine.

Confirm or deny?