Protea Survey Instruments offers a wide range of PH Tester products!

PH Tester Product Image for Protea Botswana

GroLine pH/EC/TDS Combo Tester


GroLine pH/EC/TDS Combo Tester

The HI98131 GroLine Combo offers high accuracy pH, EC (electrical 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

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:

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.