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HI98121 Waterproof ORP/pH/Temperature Tester

ORP/pH/Temperature Tester
  • The HI98121 is a reliable, waterproof tester that ensures quick and easy measurements of both pH and ORP.

    This accurate tester features 0.01 pH resolution with automatic two-point calibration and temperature compensation in a single, portable, pocket device. No more switching between meters for your routine measurements.

    ·       Waterproof 

    ·       Replaceable pH Electrode 

    ·       Automatic Two-Point pH Calibration 


    The HI98121 is a lightweight ergonomically designed tester. This tester is designed to float making it ideal for taking ORP measurements virtually anywhere. With the HI98121 it is possible to monitor both pH and ORP at the same time. The HI98121 is commonly used to monitor pH and chlorine for many applications including swimming, food sanitization, plating wastewater treatment, and cooling tower water treatment. 

    By definition pH is the measurement of the voltage generated by an electrochemical cell at zero current. The potential generated is proportional to the thermodynamic activity of the ion being measured.

    Similar to a pH measurement that quantifies the how acidic or alkaline solutions are, ORP (Oxidation Potential) measurements quantify the overall state of a solution as having the ability to oxidize or reduce a chemical species. Oxidizing and reducing reagents are used to participate in chemical reactions known as a redox reaction.

    An ORP meter must be chemically inert; it cannot be oxidized or reduced itself. It must also have the proper surface characteristics to promote rapid electron exchange, a property known as high exchange current density. Two noble metals have proven to work well for this purpose: pure platinum and pure gold are both used in the construction of ORP sensors.

    Features at-a-glance:

    ·       Waterproof

    ·       Automatic Temperature Compensation

    ·       HOLD feature

    ·       Simple to use

    ·       Economical


    pH Range

    -2.00 to 16.00 pH

    pH Resolution

    0.01 pH

    pH Accuracy

    ±0.05 pH

    ORP Range

    ±1000 mV

    ORP Resolution

    1 mV

    ORP Accuracy

    ±2 mV

    Temperature Range

    -5.0 to 60.0°C / 23.0 to 140.0°F

    Temperature Resolution

    0.1°C / 0.1°F

    Temperature Accuracy

    ±0.5°C /±1°F

    pH Calibration

    automatic, at one or two points with two sets of standard buffers (pH 4.01 / 7.01 / 10.01 or pH 4.01 / 6.86 / 9.18)

    Temperature Compensation

    automatic for pH readings

    Battery Type/Life

    1.5V (4) / approximately 250 hours of continuous use; auto-off after 8 minutes of non-use


    HI73127 replaceable pH electrode (included); fixed ORP sensor


    -5 to 50°C (23 to 122°F); RH max 100%


    163 x 40 x 26 mm (6.4 x 1.6 x 1.0’’)


    100 g (3.5 oz.)

    Ordering Information

    HI98121 (ORP/pH) is supplied with HI73127 pH electrode, HI73128 electrode removal tool, batteries and instructions.


    1 year (probe 6 months)