Many temp probes are waterproof but not submersible, and after being submerged for a few weeks/months will start to give bad readings. You might want to make sure yours is submersible if going that route. For my keezer I taped the probe to a small water bottle full of water that I keep in the corner on the hump. For my ferm chamber I tape the probe to the fermenter of the most recently brewed beer and then tape a small folded up rag on top of it.
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