What the Hanna Combo Meter Reads, and How Closely
Four values off one pen. pH runs 0.00 to 14.00 at ±0.05, and conductivity 0 to 3999 µS/cm. TDS reads 0 to 2000 ppm, with temperature from -5 to 60 °C. Every reading is temperature compensated on its own. The pH electrode is a replaceable HI73127 cartridge with an extendable cloth junction. The conductivity electrode is graphite, which resists the salt build-up that kills a budget pen. It is waterproof, and it floats.
Living With a pH and EC Meter That Floats
Calibrate the pH side against standard buffers, one point or two, and the conductivity side against a single standard. The meter expects that standard at 1413 µS/cm or 1382 mg/L, which is worth knowing before you reach for whichever bottle is nearest. The conversion factor is adjustable from 0.45 to 1.00, and the beta coefficient from 0 to 2.4% per °C. Both can be set to match the scale your feed chart uses. Four cells give roughly a hundred hours, and it powers down after eight idle minutes. The ceiling is worth checking first. Low range is in the name, and the conductivity limit covers most working feed solutions but not a concentrated stock tank.
Key Features
- Four readings, one pen: pH, conductivity, TDS and temperature, without swapping instruments mid-check.
- Replaceable pH cartridge: The HI73127 swaps out, so a spent electrode does not mean a new meter.
- Graphite EC electrode: Resists the salt and residue build-up that shortens the life of a budget pen.
- Automatic temperature compensation: pH and EC both corrected, so a cold reservoir does not skew the number.
- Waterproof, and it floats: Which is the feature you appreciate exactly once, in a full reservoir.
- Adjustable conversion factor: 0.45 to 1.00, so it can be matched to the ppm scale your feed chart uses.
- About 100 hours on four cells: With automatic shutdown after eight idle minutes.
- Low range by design: The conductivity limit suits working solutions, not concentrated stock tanks.
Technical Specifications
| Specification | Value |
|---|---|
| Brand | Hanna Instruments |
| Part Number | HI98129 |
| Type | Combo pH, conductivity, TDS and temperature tester |
| pH Range | 0.00 to 14.00 pH |
| pH Resolution | 0.01 pH |
| pH Accuracy | ±0.05 pH at 25 °C |
| pH Calibration | Automatic, one or two point, standard buffers |
| EC Range | 0 to 3999 µS/cm |
| EC Resolution | 1 µS/cm |
| EC Accuracy | ±2% of full scale |
| TDS Range | 0 to 2000 mg/L, ppm |
| TDS Resolution | 1 mg/L |
| EC and TDS Calibration | Automatic, one point at 1413 µS/cm or 1382 mg/L |
| Temperature Range | -5.0 to 60.0 °C, 23.0 to 140.0 °F |
| Temperature Accuracy | ±0.5 °C |
| Temperature Compensation | Automatic on all readings |
| Conversion Factor | Adjustable, 0.45 to 1.00 |
| Beta Coefficient | Adjustable, 0.0 to 2.4% per °C |
| pH Electrode | HI73127, replaceable, extendable cloth junction |
| EC Electrode | Graphite |
| Battery | 4 x 1.5V, about 100 hours continuous |
| Auto Shutoff | After 8 minutes of non-use |
| Housing | Waterproof, floats |
| Dimensions | 163 x 40 x 26 mm, 6.4 x 1.6 x 1.0 in |
| Weight | 100 g, 3.5 oz |
| In the Box | Meter, electrode, buffers, storage and cleaning solution, conductivity standard, removal tool, batteries, certificate and manual |