DO NOT store your pH electrode in distilled or deionised water as this will cause ions to leach out of the glass membrane and reference electrolyte, causing a slow and sluggish response. DO NOT store your pH electrode in distilled or deionised water as this will cause ions to leach out of the glass membrane and reference electrolyte, causing a slow and sluggish response. It is a solution prepared with reagent grade chemicals that that can be used to ensure optimum performance of Electrode.The life electrode is not infinite. read more