ORP standard solutions allow you to test the precision of ORP electrodes. For example, by immersing the electrode in HI 7020 solution, you should read within the 200 to 275 mV range (@20°C/68°F).
If the reading is outside the indicated interval, clean and condition your ORP electrode in HANNA® pretreatment solution. Use HI 7092 for oxidizing or HI 7091 for reducing pretreatment.
Item Number: 139623
Manufacturer: Hanna Instruments
Manufacturer's Part Number: HI 7021M