Professional-grade pH and temperature testing in a compact, waterproof pocket design. The Hanna HI98128 pHep®5 delivers laboratory-accurate measurements with 0.01 pH resolution and ±0.05 pH accuracy, featuring automatic calibration, temperature compensation, and a replaceable electrode system that extends the life of your tester for years.
Key Features & Benefits
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High precision 0.01 pH resolution – Professional accuracy of ±0.05 pH for reliable results
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Waterproof & floats – IP67 rated, designed to float if dropped in water
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Replaceable electrode – HI73127 cartridge design with extractable cloth junction extends tester life
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Auto calibration – One, two, or three-point automatic calibration with dual buffer sets
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Temperature compensation – Automatic ATC displays pH and temperature (°C or °F) simultaneously
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Extended pH range – Measures from -2.00 to 16.00 pH for versatile applications
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Long battery life – Up to 300 hours continuous use with 4 AAA batteries
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Portable & durable – Pocket-sized design perfect for field testing and on-the-go measurements
Why Choose the pHep®5?
The HI98128 pHep®5 combines advanced features typically found in expensive portable instrumentation with the convenience and affordability of a pocket tester. The innovative replaceable electrode design features a stainless steel round connector with no pins to align or break, making electrode replacement quick and foolproof. The extractable cloth junction can be renewed by simply pulling out ⅛" of material, clearing any clogging and restoring response time without replacing the entire electrode.
Advanced Features for Confident Testing
Waterproof Design
- IP67 waterproof rating protects against water immersion
- Designed to float if accidentally dropped in a tank or water body
- Ideal for wet environments, field testing, and marine applications
Expanded pH Range
- Measures from -2.00 to 16.00 pH – handles extreme acidic and alkaline solutions
- Perfect for diverse applications from aquariums to industrial testing
Automatic Temperature Compensation (ATC)
- All pH readings automatically compensated for temperature variations
- Simultaneous display of pH and temperature in °C or °F
- Temperature range: -5.0 to 60.0°C (23.0 to 140.0°F)
- Temperature accuracy: ±0.5°C / ±1°F
Stability Indicator
- On-screen clock icon disappears when reading achieves stability
- Ensures accurate, reliable measurements every time
HOLD Button
- Freezes reading on display for easy recording and documentation
- Perfect for logging measurements in challenging environments
BEPS (Battery Error Prevention System)
- Automatically shuts off if battery power is insufficient for accurate measurement
- Prevents false readings due to low battery
Auto-Off Function
- Automatically powers down after 8 minutes of non-use
- Maximizes battery life and prevents accidental drain
Flexible Calibration Options
The pHep®5 offers automatic one, two, or three-point calibration with two selectable buffer sets for maximum flexibility:
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Buffer Set 1: pH 4.01, 7.01, 10.01
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Buffer Set 2: pH 4.01, 6.86, 9.18
Choose the buffer set that best matches your testing requirements and application.
Replaceable Electrode System
The HI73127 pH electrode features an innovative cartridge design with a stainless steel round connector – no fragile pins to align or break. The extractable cloth junction allows you to renew the junction by simply pulling out ⅛" of material, clearing clogs and restoring fast response time. This extends electrode life significantly, reducing long-term costs.
Complete Kit - Ready to Test
Your HI98128 pHep®5 arrives with everything needed for immediate testing:
- HI73127 replaceable pH electrode
- HI73128 electrode removal tool
- pH 4.01 buffer solution sachets (2 × 20 mL)
- pH 7.01 buffer solution sachets (2 × 20 mL)
- HI700601 electrode cleaning solution sachet (20 mL)
- HI70300N storage solution sachet (20 mL)
- 1.5V AAA batteries (4 pcs.)
- Instrument quality certificate
- Instruction manual
Technical Specifications
| Specification |
Detail |
| SKU |
HI98128 |
| pH Range |
-2.00 to 16.00 pH |
| pH Resolution |
0.01 pH |
| pH Accuracy (@25°C/77°F) |
±0.05 pH |
| pH Calibration |
Automatic, at one, two, or three points with two sets of standard buffers (pH 4.01/7.01/10.01 or pH 4.01/6.86/9.18) |
| pH Temperature Compensation |
Automatic (ATC) |
| Temperature Range |
-5.0 to 60.0°C / 23.0 to 140.0°F |
| Temperature Resolution |
0.1°C / 0.1°F |
| Temperature Accuracy |
±0.5°C / ±1°F |
| pH Electrode |
HI73127 replaceable pH electrode with extractable cloth junction |
| Automatic Shut-Off |
Auto-off after 8 minutes of non-use |
| Battery Type / Life |
1.5V AAA (4) / Approximately 300 hours of continuous use |
| Environment |
-5 to 50°C (23 to 122°F); RH max 100% |
| Waterproof Rating |
IP67 (waterproof and floats) |
| Dimensions |
163 × 40 × 26 mm (6.4 × 1.6 × 1.0") |
| Weight |
100 g (3.5 oz.) |
Applications
- Aquariums and aquaculture
- Hydroponics and agriculture
- Water quality testing
- Swimming pools and spas
- Laboratory and educational use
- Food and beverage production
- Environmental monitoring
- Marine and reef keeping
- Wastewater treatment
Why Hanna Instruments?
Hanna Instruments is a world leader in analytical instrumentation, trusted by professionals in over 140 countries. The pHep®5 represents decades of innovation in portable pH testing, combining professional accuracy with user-friendly operation and exceptional value.
