315-75 Sodium Mono ION Selective ElectrodeION Selective Electrode for testing food, wine, swimming pools etc. About Sodium Mono ION Selective Electrode This electrode requires a separate reference electrode. Ideal for applications where greater accuracy is required (especially when ION levels are low). Applications Food Wine Swimming pools Aquaculture Aquariums Sea water Clinical analysis Specifications Dimensions: 120 x 12mm Concentration Range: Sat, 10 8M Lower Limits (ppm): 1ppb Ref.