Here is a video on how to properly remove and reattach the sensor stick.
Removing the sensor stick
Unscrew the cap of the bottle.
Grab the stick close to the lid firmly in one hand while holding the bottle cap in the other hand.
Now in snapping motion remove the sensor from the bottle lid at an angle. It is a snug fit so you will have to use force and may feel like you are breaking it, but don’t worry it is durable. Also, please don’t try to pull it straight out as that may damage the seal on the sensor stick.