GroLine Electrode Storage Solution (500 mL) HI70300 50 T76 Insert the new Model 21005 MW802BOX Insert the new Model 21005 filter cartridge into the housing The battery icon will blink to let you know it is time to change the battery so you never miss a measurement The GroLine storage solution is specifically formulated to minimize microbial growth and to prevent any diffusion osmotic effects from storing a probe in a solution with the highly concentrated inner reference electrolyte Placing the electrode in a small glass filled with storage solution or replacing the solution in the protective cap is a suitable way to store the electrode