Hanna Instruments HI98107 pHep® – Waterproof pocket pH meter for everyday water testing
The Hanna Instruments HI98107 pHep® is a compact, waterproof pocket pH meter designed to measure the acidity or alkalinity of liquids. It provides a practical solution for routine water testing in agriculture, horticulture, laboratories, aquaculture, swimming pools and general quality control. Its portable design and simple two-button operation make it suitable for beginners and experienced users who need quick pH measurements in the field or laboratory.
The meter measures pH values from 0.0 to 14.0, covering the conventional pH scale. A value below 7 indicates an acidic solution, a value of 7 indicates neutrality at the reference temperature, and a value above 7 indicates an alkaline solution. The HI98107 displays measurements with a resolution of 0.1 pH and an accuracy of ±0.1 pH at 25°C. These specifications make it suitable for routine water testing when measurements to two decimal places are not required.
How the HI98107 measures pH
The HI98107 uses an integrated pH electrode to detect the activity of hydrogen ions in a liquid. The resulting electrical signal is converted into a pH value and displayed on the LCD screen. Because the electrode is integrated into the meter, there is no need to connect a separate external probe.
An integrated temperature sensor measures the sample temperature, allowing the meter to apply automatic temperature compensation (ATC). This function adjusts the electrode's response to temperature variations. However, automatic temperature compensation does not convert the pH of every sample to its value at a reference temperature, as the actual pH of a solution can also change with temperature.
Main features and practical benefits
| Feature | Function and practical application |
| Measuring range of 0.0–14.0 pH | Suitable for routine testing of acidic, neutral and alkaline liquids. |
| 0.1 pH resolution | Displays measurement results in increments of one tenth of a pH unit. |
| ±0.1 pH accuracy | Indicates the expected measurement deviation under specified conditions. |
| Automatic temperature compensation | Adjusts the electrode response according to temperature variations. |
| Automatic calibration | Supports calibration at one or two points using suitable standard buffer solutions. |
| Integrated temperature sensor | Measures sample temperature without requiring a separate temperature probe. |
| Stability indicator | Helps identify when a measurement has stabilised sufficiently to be read. |
| Two-button operation | Provides straightforward access to power and calibration functions. |
| Renewable cloth junction | Allows a fresh section of the cloth junction to be exposed when contamination or blockage affects electrode performance. |
| Waterproof pocket design | Supports routine use in wet environments within the manufacturer's specified operating limits. |
Specifications
- Brand: Hanna Instruments
- Product model: HI98107
- Product series: pHep®
- Instrument type: Portable digital pH meter
- pH measuring range: 0.0 to 14.0 pH
- pH resolution: 0.1 pH
- pH accuracy at 25°C: ±0.1 pH
- Calibration: Automatic, one or two points
- Calibration buffers: pH 4.01, 7.01 and 10.01
- Temperature measuring range: 0.0 to 50.0°C
- Temperature resolution: 0.1°C / 0.1°F
- Temperature accuracy at 25°C: ±0.5°C / ±1.0°F
- Temperature compensation: Automatic, 0 to 50°C
- Power supply: CR2032 3V lithium coin-cell battery
- Battery life: Approximately 800 hours of continuous use
- Automatic shut-off: Selectable 8 minutes, 60 minutes or disabled
- Operating temperature: 0 to 50°C
- Maximum relative humidity: 100%
- Dimensions: 160 × 40 × 17 mm
- Weight: Approximately 65–75 g
- Electrode design: Integrated pH electrode with renewable cloth junction
- Operation: Two-button control
- Temperature sensor: Integrated
- Waterproof design: Yes
- Compatible accessories: Suitable pH calibration buffers and electrode cleaning solutions for the HI98107
Electrode compatibility and replacement
The HI98107 uses an integrated electrode rather than a conventional replaceable probe. This distinction is important when selecting accessories and planning long-term maintenance.
The meter features a renewable cloth junction, which can help extend electrode service life when the junction becomes contaminated or obstructed. According to the manufacturer's instructions, the cloth junction can be carefully extended to expose a fresh section. This may help restore the performance of the reference junction, but it does not replace the entire electrode.
The Hanna Instruments HI73127 is a replacement electrode for specifically compatible Hanna Instruments pocket testers, including models such as the HI98127 and HI98128. It should not be assumed to fit the HI98107, which has an integrated electrode design.
For product catalogue purposes, the following distinctions are important:
- HI98107: Complete pH meter with an integrated electrode.
- HI73127: Replacement electrode for specifically compatible Hanna Instruments pocket testers; not a confirmed replacement for the HI98107.
- pH calibration buffers: Solutions used to calibrate the meter and establish reliable reference points.
- Electrode cleaning solution: Used to remove residues that may affect electrode performance.
- Electrode storage solution: Used when recommended for the particular electrode design, following the manufacturer's instructions.
Suitable applications
The HI98107 is suitable for routine pH measurements in several environments:
- Agriculture and horticulture: Checking the pH of irrigation water and other suitable aqueous samples.
- Aquaculture and fish farming: Monitoring water conditions as part of a broader water quality management programme.
- Swimming pools and spas: Checking water pH as part of routine maintenance.
- Laboratories and quality control: Performing basic pH checks on suitable liquid samples.
- Environmental monitoring: Taking field measurements of freshwater samples.
- Food-related applications: Measuring suitable liquid samples when the required accuracy and electrode design meet the application's requirements.
The HI98107 is intended for general-purpose pH measurements. Viscous, oily, heavily contaminated or chemically aggressive samples may require a different electrode design. Its 0.1 pH resolution also makes it less suitable for applications requiring fine pH differentiation.
Calibration, operation and maintenance
Calibration should be performed using fresh, suitable buffer solutions. For routine measurements, pH 7.01 can serve as one calibration point, while pH 4.01 or pH 10.01 can provide a second point, depending on the expected sample range.
Samples should be measured according to the manufacturer's instructions, and readings should be recorded once they have stabilised. After use, the electrode should be cleaned as appropriate and stored according to the instructions supplied with the instrument. Prolonged storage in unsuitable liquids or allowing the sensing area to dry out can affect measurement performance.
The HI98107 is supplied with the following items according to the manufacturer's ordering information:
- Protective cap
- CR2032 battery
- One pH 4.01 buffer solution sachet
- Two pH 7.01 buffer solution sachets
- Electrode cleaning solution sachet
- Instruction manual
- Instrument quality certificate
Important considerations before use
The HI98107 is designed for routine pH testing rather than high-resolution analytical work. Its 0.1 pH resolution should be considered when selecting a meter for applications with strict measurement tolerances. Automatic temperature compensation helps account for temperature-related changes in electrode response but does not eliminate temperature effects on the sample itself.
Although the instrument is described as waterproof, the precise conditions for immersion and exposure should be checked in the relevant manual. Waterproof construction should not automatically be interpreted as suitability for prolonged underwater operation or every chemical environment.
For applications requiring a replaceable electrode, a resolution of 0.01 pH, or a specialised sensing tip, another Hanna Instruments model may be more appropriate.
