Hanna Instruments HI98127 pHep®4 – Waterproof Digital Meter for pH and Temperature Measurements
The Hanna Instruments HI98127 is a waterproof digital meter designed to determine the pH and temperature of liquids. It is part of the pHep®4 product line and is designed to perform measurements of water and other liquids. The meter provides a convenient combination of portability, automatic calibration, automatic temperature compensation and a replaceable pH electrode.
The pH number shows whether the solution is acidic or basic. A pH less than 7 is indicative of an acidic solution, 7 pH is neutral at 25°C, and a pH above 7 indicates a basic solution. Control of pH is required in cases where the change in the chemical composition of the water can affect its suitability for its intended application, such as irrigation, hydroponics, aquariums, swimming pools and water purification.
The HI98127 provides pH measurements in the range of −2.0 to 16.0 pH, with a resolution of 0.1 pH and an accuracy of ±0.1 pH. Temperature is measured within the range of −5.0 to 60.0°C, with a resolution of 0.1°C and an accuracy of ±0.5°C at 20°C. Both values are displayed simultaneously on the LCD screen.
How the pHep®4 Works
The Hanna Instruments HI98127 uses a replaceable electronic pH electrode to measure the activity of hydrogen ions in the liquid. Such activity generates an electrical current which is translated into pH readings by the tester. Due to temperature dependence of the electrode's performance, the tester also has a temperature sensor.
The automatic temperature compensation (ATC) accounts for the effects of temperature on the electrode's performance. In this way, it allows increasing the accuracy of measurements of samples with different temperatures. However, ATC does not transform the pH of the sample into a value at some other temperature, nor does it eliminate any chemical changes in pH caused by the temperature.
Before conducting any measurements, the meter must be calibrated using the standard pH buffer solutions. Calibration involves comparing the meter's response of the electrode with known values of pH. The HI98127 allows automatic one-point or two-point calibration with the help of standard buffer sets of pH 4.01, 7.01 and 10.01 or pH 4.01, 6.86 and 9.18.
Features and Benefits of Hanna Instruments HI98127 pHep®4
- Waterproof housing – makes the tester suitable for work in wet environment; designed to float in case of accidental drop in water.
- Replaceable pH electrode – allows separate replacement of the electrode in case of wear or damage without replacement of the entire tester.
- Automatic calibration – simplifies calibration with the help of compatible standard buffer solutions.
- Automatic temperature compensation – allows compensating for the temperature influence on the electrode performance.
- LCD dual level display – displays both the pH and temperature simultaneously.
- Stability indication – shows when the measurement has been stabilized.
- HOLD function – freezes the displayed value of measurement to simplify the process of result record.
- Battery status indicators – shows the battery percentage during startup, battery status during operation.
- Automatic shut off – prolongs battery life when the tester is not in use.
Specifications of Hanna Instruments HI98127 pHep®4
- Brand: Hanna Instruments
- Model: HI98127
- Product line: pHep®4
- Parameters: pH and temperature
- Measuring range pH: −2.0 to 16.0 pH
- pH resolution: 0.1 pH
- pH accuracy: ±0.1 pH
- Measuring range Temperature: −5.0 to 60.0°C
- Temperature resolution: 0.1°C
- Temperature accuracy: ±0.5°C at 20°C
- Calibration: Automatic, one point or two points
- Temperature compensation: Automatic
- Electrode: Replaceable HI73127 pH electrode
- Power source: 4 × 1.5 V batteries
- Battery life: Up to 300 hours of continuous use
- Dimensions: 163 × 40 × 26 mm
- Weight: Approximately 100 g
- Environment of operation: From −5 to 50°C; relative humidity not exceeding 100%
Applications of Hanna Instruments HI98127 pHep®4
The HI98127 can be used in a wide range of locations requiring routine pH and temperature measurements.
- Agriculture and horticulture – measuring pH of the irrigation water and nutrient solutions for supporting water quality management.
- Hydroponic systems – determination of the acidity of nutrient solutions used in soilless cultivation.
- Aquariums and fish farms – measuring of water parameters as a part of the routine water quality control.
- Swimming pools – determination of the pH of the water during routine maintenance.
- Laboratories – carrying out routine measurements of liquid samples.
- Water purification – checking pH during water quality analysis and treatment process.
The tester can measure pH and temperature only. It does not measure electric conductivity (EC), total dissolved solids (TDS) or any particular nutrient content of water. For this purpose, additional meters are required.
Calibration, Operation and Maintenance of Hanna Instruments HI98127 pHep®4
Correct calibration and maintenance of the electrode are essential for getting accurate results. The following guidelines describe the procedure of routine operation.
- Preparing the sample – collection of a representative liquid sample in a clean vessel, if needed.
- Calibration – using new, compatible pH buffers solutions and performing the calibration according to the manufacturer's recommendations. The two-points calibration can increase the accuracy of the measurements in the relevant range of pH.
- Rinsing of the electrode – rinsing the electrode with clean water between measurements to prevent contamination.
- Measurements – immersing the electrode into the sample and waiting for the measurement to stabilize.
- Cleaning and storage of the electrode – using an electrode cleaning solution if needed and storing the electrode in the appropriate storage solution. It is not recommended to dry the electrode except when explicitly indicated by the manufacturer.
The HI98127 uses a replaceable HI73127 electrode cartridge with an expandable cloth junction. In case of the contamination of the junction, the cloth can be expanded to reveal a clean surface. The electrode can be removed by means of the HI73128 electrode removal tool.
Accessories Included with Hanna Instruments HI98127
According to the product information of the manufacturer, Hanna Instruments HI98127 package includes the following items:
- HI73127 replaceable pH electrode
- HI73128 electrode removal tool
- pH 4.01 calibration buffer sachets
- pH 7.01 calibration buffer sachets
- Electrode cleaning solution sachet
- Electrode storage solution sachet
- Batteries
- Instruction manual
Differences Between Hanna Instruments HI98127 and HI98107
Hanna Instruments HI98127 pHep®4 and Hanna Instruments HI98107 pHep® are portable pH testers providing measurements of both pH and temperature. Both the models provide a pH resolution of 0.1 and an accuracy of ±0.1 pH. The main differences lie in measuring ranges, physical dimensions, electrode design, batteries and the battery life.
Main differences
- pH measuring range: HI98127 measures from −2.0 to 16.0 pH, HI98107 measures from 0.0 to 14.0 pH.
- Temperature range: The HI98127 has a measurement range of −5.0 to 60.0°C, the HI98107 can measure temperatures from 0.0 to 50.0°C.
- Electrode design: The HI98127 has a replaceable HI73127 electrode cartridge. The HI98107 has a renewable cloth junction.
- Battery: HI98127 works on four 1.5 V batteries, HI98107 uses a CR2032 3 V lithium battery.
- Battery life: HI98127 has a battery life of approximately 300 hours of continuous use, HI98107 provides 800 hours of continuous use.
- Dimensions and weight: HI98127 has a dimension of 163 × 40 × 26 mm and weight of approximately 100 g, HI98107 has dimensions of 160 × 40 × 17 mm and weighs approximately 75 g.
- Waterproof design: Both models provide waterproofing.
Choosing Between Hanna Instruments HI98127 and HI98107
The Hanna Instruments HI98107 is lighter and thinner, having a longer claimed battery life. Its pH range of 0.0–14.0 is suitable for most of the routine water tests.
The Hanna Instruments HI98127 provides a wider pH range, a broader temperature range and a replaceable electrode cartridge. Such properties may be helpful when measurements outside the ranges provided by HI98107 are needed or the possibility of a separate replacement of the electrode is preferable.
