The perfect solution to store and hydrate your Bluelab pH products. It is extremely important to care for and store pH probes correctly. pH probes are sensitive glass instruments which age through normal use. The life and performance of pH probes is reduced heavily when they are stored dry. Bluelab pH Probe KCI Storage Solution is made specifically for use with Bluelab pH products. It is designed to increase response time and maximize the life of Bluelab pH pens and pH probes. For best results, use the KCI solution to store the pH pen/probe after use and hydrate monthly. Instructions are on the label of the bottle. Bluelab pH probe KCI Storage Solution is manufactured to high laboratory standards. Remember - keep your pH probe wet. Always. If it dries, it dies!.