Hanna Instruments HI 98121 pH, and OPR tester combines a convenient way to measure both your pH and ORP. the Hi 98121 is one of the handiest hot tub accessories as it also features a built in thermometer, constantly dispalying the temperature on the dual level LCD. The Hi 98121 also features the ease of using common batteries with a display of battery life percentage remaining, making the Hanna Instruments 98121 one of the best hot tub supplies you can buy.
Product (ID #: HI 98121)

Make sure to keep your HI 98121 fully stocked with extra:
HI7004P - pH 4.01 buffer solution @ 25°C-20 ml sachet (25 pcs)
HI7007P - pH 7.01buffer solution @ 25°C- 20 ml sachet (25 pcs)
HI70010P - pH 10.01 buffer solution @ 25°C- 20 ml sachet (25 pcs)
HI70300M - Storage solution for pH /ORP electrodes, 0.23 L
HI73127 - Spare electrode for HI98127 & HI98128