The Bluelab BLU1008 pH Probe KCI storage solution is made specifically for Bluelab pH products. It is manufactured to increase response time and maximize the life of Bluelab pH pens and pH probes. Use this KCI solution to store the pH probe after use and hydrate monthly. Instructions are on the label of the bottle. For best results and longevity, keep your pH probe wet. If it dries, it dies.