When and how to clean chemistry controller sensors is pretty straight forward. However, one very critical area seems to elude many operators, and that is how to store sensors when the pool is shut down for a period of time for maintenance.
It is critical that the sensors always remain hydrated or they will dry out and require you to purchase replacements, potentially a costly mistake.
The simplest way to accomplish this is to be sure to leave water in the flow cell chambers when you shut the circulation down, by isolating the flow cell with water visibly covering the sensors.
An additional safety step would be to set a reminder in a cell phone to check on the sensors daily to ensure that they are always hydrated.
A second option would be if you have the original containers the sensors arrived in, these should be watertight and an acceptable way to store the sensors, just be sure that there is enough water in the container to more than cover the tips.