Hanna HI98127 & HI98128 Waterproof Pen-Style pH Meters

Overview

The Hanna HI98127 and HI98128 are compact, rugged pen-style pH meters engineered for reliable field and benchtop measurements across diverse environments—from quality control in food processing facilities and municipal water sampling to educational labs and agricultural soil testing. These instruments operate on the fundamental principle of potentiometric pH measurement: a glass pH electrode generates a millivolt signal proportional to hydrogen ion activity in solution, referenced against a stable internal Ag/AgCl reference system. Integrated automatic temperature compensation (ATC) ensures thermally corrected readings without manual input, critical for accuracy when measuring samples at non-standard temperatures (–5 to 50 °C). Unlike basic pocket testers, the HI98127/128 feature replaceable electrodes—extending service life and enabling recalibration verification—while maintaining true portability and operational simplicity.

Key Features

• IP67-rated waterproof housing certified for immersion up to 1 meter for 30 minutes, suitable for wet-lab, outdoor, or industrial washdown environments.
• Large backlit LCD with dedicated stability indicator (icon-based) and clear numeric display for rapid visual confirmation of measurement readiness.
• Two-button interface (ON/OFF and CAL/READ) minimizes operational error; no menu navigation required for routine use.
• Automatic buffer recognition during calibration eliminates manual selection—supports standard two-point calibration using pH 4.01/7.01 or 7.01/10.01 buffers.
• Replaceable electrode module with built-in temperature sensor enables consistent ATC performance and simplifies maintenance without instrument replacement.
• BEPS (Battery Error Prevention System) actively monitors battery voltage and displays low-power warning before measurement drift occurs—ensuring data integrity throughout battery life.
• Configurable auto-off timer (default 8 minutes) conserves battery while supporting extended field deployment without compromising measurement continuity.

Sample Compatibility & Compliance

The HI98127 and HI98128 are validated for aqueous solutions within the specified pH range (–2.0 to 16.0), including buffered standards, drinking water, wastewater effluents, hydroponic nutrient solutions, and mild acidic or alkaline process streams. Electrode design accommodates samples with moderate turbidity or low conductivity (>200 µS/cm); for low-ionic-strength samples (e.g., deionized water), optional HI70300 pH storage solution and frequent calibration are recommended. While not certified for hazardous area use, the meters meet CE marking requirements for electromagnetic compatibility (EMC Directive 2014/30/EU) and low-voltage safety (LVD Directive 2014/35/EU). Their design supports traceable calibration records aligned with ISO/IEC 17025 clause 7.7 (sampling and measurement uncertainty considerations) and facilitates audit-ready documentation under GLP and GMP frameworks where portable pH verification is required.

Software & Data Management

These pen-style meters operate as standalone field instruments with no onboard data logging or PC connectivity. All calibration events, measurement values, and temperature readings are displayed in real time but not stored internally. This architecture prioritizes robustness, battery longevity, and regulatory simplicity—eliminating concerns related to electronic record retention, 21 CFR Part 11 compliance, or software validation. Users maintain full control over data integrity by recording measurements manually or via external devices (e.g., calibrated logbooks, LIMS-integrated mobile apps, or barcode-scanned field tablets). Calibration certificates for included buffers (HI7004, HI7007, HI7010) are available upon request to support metrological traceability to NIST-traceable standards.

Applications

• Field monitoring of surface water, groundwater, and wastewater pH per EPA Method 150.1 and ASTM D1293.
• Routine QC checks in beverage production, dairy processing, and brewing operations where rapid pH verification between batches is essential.
• Educational demonstrations of acid-base chemistry and electrode response kinetics in undergraduate chemistry laboratories.
• Agricultural extension services assessing soil extract pH (saturated paste or 1:1 water extracts) prior to lime or fertilizer application.
• Maintenance of aquaculture systems, hydroponic reservoirs, and swimming pool chemical balance protocols.
• Verification of cleaning-in-place (CIP) rinse water neutrality in pharmaceutical manufacturing environments.

FAQ

What is the difference between the HI98127 and HI98128 models?
The HI98127 includes a single replaceable pH electrode (HI1285-5), while the HI98128 ships with two electrodes (HI1285-5 + spare), offering extended operational readiness for high-frequency field use.
Can these meters measure pH in non-aqueous or high-alcohol solutions?
No—they are optimized for aqueous media. Non-aqueous solvents may cause reference junction clogging or glass membrane dehydration, leading to drift and inaccurate readings.
Is calibration verification possible without standard buffers?
No. Two-point calibration using certified pH standards is mandatory for traceable accuracy; deviation from ±0.1 pH tolerance requires electrode cleaning or replacement.
How often should the electrode be replaced?
Under normal use (≤10 measurements/day), the HI1285-5 electrode typically lasts 12–18 months; performance degradation is indicated by slow response, unstable readings, or failure to calibrate within specification.
Does the meter support custom calibration points?
No—only automatic recognition of factory-defined buffer sets (pH 4.01/7.01 or 7.01/10.01) is implemented to ensure repeatability and reduce user error.