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SKU HI98131 Category Tag

GroLine pH/EC/TDS Combo Tester HI98131

HI 98131 simultaneously measures pH, conductivity, total dissolved solids (TDS) and temperature. Easy to use, fast and accurate, it is ideal for routine crop surveys. With exchangeable pH electrode.

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The HI98131 GroLine Combo offers high accuracy pH, EC (conductivity), TDS

(total dissolved solids), and temperature measurements in a rugged, waterproof casing that floats.

The GroLine Combo features a replaceable pH electrode with extendable cloth junction as well as an EC/TDS graphite electrode.

The renewable cloth junction provides an extended electrode life and the replaceable pH cartridge means that this tester does not need to be thrown away when the pH sensor is exhausted.

The EC/TDS conversion factor is user-selectable, as well as the temperature compensation coefficient (β).


  • Waterproof
    • Designed to withstand the humidity of a growing environment
  • Automatic one-point calibration using our Quick Cal solution
  • Automatic Temperature Compensation
    • All readings are compensated for variations in temperature
    • Temperature displayed in °C or °F along with pH reading
  • Measurement instability indicator
    • Meter displays a clock tag that will disappear when the reading has achieved stability
  • HOLD button
    • Freezes reading on the display to allow recording of measurement
  • BEPS (Battery Error Prevention System)
    • Meter will automatically shuts off if there is not enough power to get an accurate measurement
  • Battery % level at startup
  • Low Battery Indicator
  • Auto-off
    • Automatically shuts off after 8 or 60 minutes of non-use to maximize battery life
Calibrate pH and EC with one solution

Calibrate pH and EC with one solution

Calibration of both pH and EC can be performed using our Quick Cal calibration solution

HI98131 Pocket Clip

Pocket Clip

A pocket clip is featured on the back of the the GroLine Combo

HI98131 Supplied complete

Supplied complete

Supplied with all the tools necessary to start performing tests

High accuracy EC/TDS graphite probe

High accuracy EC/TDS graphite probe

The graphite conductivity probe provides greater accuracy because it cannot be contaminated by salt deposits in the solution.The exposed temperature sensor provides fast response times and guarantees highly accurate temperature compensated readings.

Replaceable pH electrode cartridge

Replaceable pH electrode cartridge

The Combo features an easy-to-replace pH electrode.The sturdy, snap-in connector means there are no pins to bend or break.

Extendable cloth junction

Simply pull out 3 mm (1/8”) and cut when the cloth junction becomes dirty to improve response time and stability.




0.00 to 14.00 pH


0.01 pH


±0.1 pH


automatic, one or two-point calibration (using pH 4.01, 7.01, 10.01 buffers); one-point calibration using HI5036 or HI50036 Quick Cal calibration solution

Temperature Compensation




0.00 to 6.00 mS/cm


0.01 mS/cm


±2% F.S.


automatic, one-point at 1.41 mS/cm or 5.00 mS/cm; one-point calibration using Quick Cal calibration solution

Temperature Compensation

automatic, with β = 1.9%/°C



0 to 3000 ppm (500 CF); 0 to 3999 ppm (700 CF)


10 ppm (mg/L)


±2% F.S.

Conversion Factor

0.5 (500 ppm) or 0.7 (700 ppm)



0.0 to 60.0°C / 32.0 to 140.0°F


0.1°C / 0.1°F


±0.5°C /±1°F

Additional Specifications

pH Electrode

HI73127 (replaceable; included)


0 to 50°C (32 to 122°F); RH max 100%

Battery Type / Life

1.5V (4) / approx.100 hours of continuous use; auto-off after 8 min or 60 min of non-use; can be disabled

Dimensions / Weight

163 x 40 x 26 mm (6.4 x 1.6 x 1.0’’) / 100 g (3.5 oz.)

Ordering information

HI98131 (GroLine Combo) is supplied with HI73127 pH electrode, electrode removal tool, Quick Cal calibration solution sachets (4), electrode cleaning solution sachet, batteries, storage cap, quality certificate and instruction manual.

Additional Informations

Additional information


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