GroLine pH/EC/TDS Combo Tester HI98131

In stock

The HI98131 is a slim, lightweight, and waterproof pocket tester that measures pH, conductivity (EC), TDS (ppm), and temperature. Simple, two-button meter operation and advanced features, including a selectable EC to TDS conversion factor (0.5 - 500 ppm and 0.7 - 700 ppm). for your essential testing.

  • All measurements in a single, hassle-free tester.
  • Quick Cal solutions to calibrate pH and conductivity all at once with a single solution.
  • Perfect for hydroponics, greenhouse, and agriculture use.

The HI98131 GroLine pH and TDS water tester feature a large multi-level LCD that displays both pH, EC or TDS and temperature readings simultaneously. The pH readings are displayed with a 0.01 resolution and with an accuracy of +/-0.05 pH, while the EC and TDS readings are displayed with a 0.01 mS/cm and 10 ppm (mg/L) resolution and 2% full-scale accuracy. The EC range of the HI98131 is from 0.01 to 6.00 mS/cm and TDS is from 0 to 3000 ppm using a 0.5 conversion factor. The HI98131 also offers the option to use a 0.7 (700 ppm) EC to TDS conversion factor. An exposed temperature sensor allows for rapid temperature compensated measurements of EC and TDS. The LCD screen has indicators for calibration status and stability. The battery percent level is displayed at start up alerting the user to the remaining battery power that is available. The HI98131 is a versatile pocket meter designed for hydroponics, greenhouse and agriculture applications.






Simplified one-button calibration

One or two-point pH calibration is automatic to a pre-programmed buffer set (4.01, 7.01 and 10.01) or single point pH and EC calibration with the Hanna Quick Cal calibration solution. To perform a quick cal calibration, simply press and hold the left power/mode button while in measurement mode for three seconds and let go to enter calibration mode. Once both pH and EC are calibrated "CAL OK" is displayed and the meter returns to measurement mode.

HI73127 Replaceable pH electrode

The HI99131 TDS water tester is supplied with the HI73127 replaceable pH electrode. This electrode features an extractable junction that can be pulled 1/8" out to clear any clogging that results in drifting and erratic readings.




3 sensors in a single meter

  • pH electrode with extractable junction
  • Amperometric EC/TDS sensor
  • Exposed temperature probe for faster EC/TDS readings
  • Designed to withstand the humidity of a growing environment

Wide pH Range

  • pH range is from 0.00 to 14.00 pH


Selectable EC to TDS conversion factor

  • Choice of either a 0.5 or 0.7 conversion factor
    0.5 (500 CF) conversion factor is for an EC reading of 1000 μS/cm = 500 ppm
    0.7 (700 CF) conversion factor is for an EC reading of 1000 μS/cm = 700 ppm


Automatic Temperature Compensation

  • All readings are compensated for variations in temperature
    Temperature displayed in °C or °F along with pH, EC or TDS reading


Stability 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 shut off if there is not enough power to get an accurate measurement


Low Battery Indicator

  • When the level is below 5%, the battery symbol on the LCD blinks to indicate a low battery condition.



  • Selectable time before meter will automatically shut off to conserve battery life. Options are after 8 minutes, 60 minutes, or disabled.


Battery % level at startup





Specification Name Detail
sku HI98131
pH Range 0.00 to 14.00 pH
pH Resolution 0.01 pH
pH Accuracy (@25°C/77°F) ±0.10 pH
pH Calibration automatic, one or two-point calibration (using pH 4.01, 7.01, 10.01 buffers); one point calibration using HI50036 Quick Cal pH and EC one-point calibration solution
Temperature Range 0.0 to 60.0 °C (32.0 to 140.0 °F)
Temperature Resolution 0.1 °C (0.1 °F)
Temperature Accuracy (@25°C/77°F) ±0.5 °C (±1.0 °F)
EC Range 0.00 to 6.00 mS/cm
EC Resolution 0.01 mS/cm
EC Accuracy (@25°C/77°F) ±2% F.S.
EC Calibration automatic, one-point at 1.41 mS/cm or 5.00 mS/cm; one point calibration using Quick Cal pH and EC one-point calibration solution
TDS Range 0 to 3000 ppm (0.5 CF); 0 to 3999 ppm (0.7 CF)
TDS Resolution 10 ppm (mg/L)
TDS Accuracy (@25°C/77°F) ±2% F.S.
TDS Conversion Factor 0.5 (500 ppm) or 0.7 (700 ppm
Temperature Compensation pH: automatic; EC: automatic, with β= 1.9%/°C
Power Supply 1.5V batteries (4 pcs.)
Power Consumption approximately 100 hours of continuous use
Environment 0 to 50 °C (32 to 122 °F); RH max. 100%
Dimensions 163 x 40 x 26 mm (6.4 x 1.6 x 1.0”)
Weight 95 g (3.4 oz)
Ordering Information HI98131 is supplied with HI73127 pH electrode, HI73128 electrode removal tool, batteries (4), instructions and quality certificate.
Warranty This meter is warranted for a period of one year against defects in workmanship and materials when used for their intended purpose and maintained according to instructions. The electrode is warranted for a period of six months.