» Equipment & Tools » PHB-21 Portable pH Meter: Multi-Reading, NIST Standard Buffers

PHB-21 Portable pH Meter: Multi-Reading, NIST Standard Buffers

February 5, 2026

The Metalsin PHB-21 is a rugged, handheld portable pH meter specifically engineered for demanding field and outdoor measurements. Whether you are conducting on-site testing for municipal potable water or monitoring treatment progress in wastewater and reclaimed water systems, the PHB-21 provides laboratory-grade reliability in a compact, mobile format.

PHB-21 portable pH meter.

The PHB-21 portable pH meter, furnished with a shock-absorbing silicone-rubber protection case, a wristband, and NIST buffers.

Versatile Multi-Reading Modes for Field Efficiency

To meet the diverse needs of field technicians, the PHB-21 features a sophisticated Multi-reading system that allows for both Auto-read and Continuous-read modes. In “Auto-read” mode, the meter provides a stable, finalized result once the electrode signal stabilizes, ensuring consistent data recording. Conversely, the “Continuous-read” mode is invaluable for monitoring real-time pH fluctuations in flowing streams or active treatment processes. This flexibility allows for rapid assessment of raw water intake or effluent discharge without sacrificing accuracy.

Precision Calibration with NIST Standard Recognition

Accuracy in the field depends on proper calibration, and the PHB-21 makes this process foolproof. It supports 1-3 points calibration with Automatic Recognition of NIST standard buffers (pH 4.01, 7.00, and 10.01). By automatically identifying the standard solution, the PHB-21 eliminates the risk of human error during setup. This ensures that your measurements are always traceable to international standards, providing the high-level data integrity required for regulatory environmental monitoring and industrial quality control.

Rugged Design and Intelligent Utility

The PHB-21 features an IP65 waterproof rating, making it the ideal choice for challenging outdoor environments where exposure to dust and water is common. The unit features a crisp 3.5-inch LCD display and an Auto-hold feature to lock in measurements. Precision is guaranteed by Automatic/Manual Temperature Compensation (ATC/MTC), correcting for outdoor thermal fluctuations. With a 200-set data capacity, Auto-power off to save battery, and a one-touch reset feature to restore factory defaults, the PHB-21 is the ultimate tool for reliable, long-term field measurement.

Technical Parameters & Operation Manual

pHRange-2.00 to 18.00 pH
Resolution0.01pH
Accuracy±0.01pH
Calibration PointsUp to 3
Auto RecognitionNIST buffers
mVRange-1999 to 1999 mV
Resolution1 mV
Accuracy±0.1%FS
TemperatureRange-5 to 110 ºC
UnitºC
Resolution0.1ºC
Accuracy±0.2ºC
MeasurementReadingAuto, Continuous
PromptsReading, Stable, Locked
Temp. CompensationATC, MTC
DataStorage200 results each
InputspH ElectrodeBNC(Q9)
Temp. Probe4-pin aviation connector
DisplayBacklightYes
Auto ShutdownEvery 300 sec.
IP RatingIP65
GeneralPowerRechargeable Lithium battery, AC Adapter, 100-240V AC input, DC5V output
Dimensions82×227×36
Weight0.41kg
*Click to download and view the operation manual for PHB-21 portable pH meter.

Model Numbers of Portable pH Meters
PHB-21PHB-31PHB51
*Click to view full series of pH meters supplied by Metalsin.

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