Two issues have cropped up recently with the Pool Temperature Monitor. The first one is related to my code. There have been two instances where it stopped sending updates to Adafruit IO but continues to work if reset. We are pretty sure the first time this happened my parents house lost internet overnight and obviously my code did not handle it well. I plan on pulling it out this week to try and fix that issue.
The second problem is related to moisture. The last time it stopped working I pulled it out and noticed condensation collecting on the top of the screw cap. There was also some additional liquid at the bottom which has slightly rusted the BB's. My parents said the last time my kids were swimming my son pulled it underwater so that may be the initial source of the moisture or it may just be naturally happening.
I used thread sealant that is really old so I also plan on cleaning it up and applying some fresh sealant. Some people have suggested adding a solar panel but waterproofing was the main reason I did not try this approach. There is obviously a way to do it well but I did not want that additional complexity.