The only electrodes that must be always stored in storage solutions and can be damaged if stored dry are the probes that use Polymer electrolyte, such as our probes for PH60S, SX811-SS and SX811-BS meters. These Probes are made with a different type of material and over time will be damaged if stored dry.
Our other regular glass bulb pH electrodes (like the ones for PH60 and PH20) use the storage solution to keep hydrated. Keeping them soaked in the 3M KCL storage solution is a recommended good practice. For our portable and benchtop pH meters, the pH electrodes come with a storage cap, which allows the elctrode to be soaked in KCL solution all the time when not in use. However, even stored dry, our pH electrodes per se will NOT get damaged. They just lose a bit sensitivity and accuracy temporarily. Users can always “revive” the sensor by soaking it in the KCL storage solutions (the longer the better). For lower accuracy meters like PH20, soaking 5-10 minutes in tap water will work just fine.
DO NOT soak or store any pH probes in pure water like distilled water, deionized water, or reverse osmosis water for it could cause damage to the pH electrode. Rinse the probes in pure water is a good practice, but never store them in pure water.
Other brands' storage solutions are NOT RECOMMENDED for use with Apera's pH sensors, since they may use different formulas and could cause potential permanent damage to Apera's pH sensors.