HI98131 GroLine Waterproof Combo Tester and Related Products


For a limited time: 

Add 11+ HI98131 testers to your cart and get 1 free, the credit will apply at checkout.  Add 22+ units to get 2 free, etc. 

HI98131 looks a lot like the "black combo pen" you may be familiar with.  We improved that black combo tester and made this GroLine version.  What did we improve? 

  • We cleaned up the menu and made it so that only the 500 or 700 TDS/ppm scales could be chosen.  The black combo tester allowed customers to select custom TDS scales which is not needed for growers and caused them confusion. 
  • We removed the ability to adjust the temperature beta compensation settings because growers didn't need this and it also caused them confusion. 
  • We added the ability to use QuickCal combo solution making the meter quicker and easier to calibrate. 
  • We added calibration and cleaning solutions, initial solutions are now included with the new version of the meter. 
  • We greatly improved its packaging so it looks good on your store's shelf. 

While the black combo tester is a well known Hanna "flagship" product, the new improved HI98131 white GroLine combo tester is much better for growers to use and retailers to stock.  

  • HI98131 Combo Tester is waterproof and measures pH/EC/PPM/Temp.  This pocket sized tester does everything that the HI9814 Combo Meter can do.  

    • All measurements in a single, hassle-free tester.
    • Quick Cal combo solution calibrates pH and conductivity all at once with a single solution.
    • Easily replaceable pH electrode  
    • Simplified menu compared to the past black combo pen (HI98129)
    • Features at-a-glance

      • 3 sensors in a single meter

      pH electrode with extractable junction

      Amperometric EC/TDS sensor

      Exposed temperature probe for faster EC/TDS readings

      • Waterproof

      Designed to withstand the harsh grow room environments. 

      • 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 1.00 mS/cm = 500 ppm
      0.7 (700 CF) conversion factor is for an EC reading of 1.00 mS/cm = 700 ppm
      • Automatic Temperature Compensation
      All readings are compensated for variations in temperature
      Temperature displayed in oC or oF 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
      • Battery % level at startup
      • Low Battery Indicator
      When the level is below 5%, the  battery symbol on the LCD blinks to indicate a low battery condition.
      • Auto-off - Selectable time before meter will automatically shuts off to conserve battery life. Options are after 8 minutes, 60 minutes , or disabled.

      pH Range

      0.00 to 14.00 pH

      pH Resolution

      0.01 pH

      pH Accuracy

      ±0.1 pH

      pH Calibration

      automatic, at one or two points using standard buffers (pH 4.01, 7.01,10.01); one point calibration using quick calibration solution

      Conductivity Range

      0.00 to 6.00 mS/cm

      Conductivity Resolution

      0.01 mS/cm

      Conductivity Accuracy

      ±2% F.S.

      TDS Range

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

      TDS Resolution

      10 ppm (mg/L)

      TDS Accuracy

      ±2% F.S.

      Temperature Range

      0.0 to 60.0°C / 32.0 to 140.0°F

      Temperature Resolution

      0.1°C / 0.1°F

      Temperature Accuracy

      ±0.5°C /±1°F

      Temperature Compensation

      pH: automatic; EC/TDS: automatic with β set at 1.9%/°C

      EC/TDS Calibration

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

      TDS Conversion Factor

      0.5 (500 ppm) or 0.7 (700 ppm)

      Battery Type/Life

      1.5V (4) / approx. 100 hours of continuous use, auto-off after 8 minutes of non-use


      after 8 minutes, 60 minutes, disabled


      0 to 50°C (32 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

      HI98131 is supplied with HI73127 pH electrode, HI73128 electrode removal tool, batteries (4), instructions and quality certificate.