For storage of a period of weeks, rinse the electrode with distilled water and place the pH electrode in a soaker bottle filled with a solution consisting of equal parts 4M Potassium Chloride (KCl) and pH 4 buffer solution, which can be made from an SC-2321 buffer capsule, and (optionally) a few drops of pH buffer preservative (included in the SC-2321 pH buffer kit). KCl is a common salt which may be obtained from most chemical suppliers.
You can also purchase pH storage solution as SC-3507.
You may store the pH electrode indefinitely in that solution, but for long term storage, we recommend storing the electrode dry. Once the glass electrode membrane dries out it must be restored.
If the restoring procedure fails to improve the response of the electrode, it should be replaced with a new PS-2573 electrode.