About Horiba
Founded around 74 years ago, Horiba has grown into a multinational company that produces a comprehensive collection of scientific equipment that includes environmental measuring equipment and scientific analysers.

Figure 1 Horiba U-50 Series Water Quality Tester
Introduction to the U-50 Series
Horiba manufacture water quality meters that vary from inexpensive pocket meters to professional meters designed for field or laboratory use. As part of the professional, field-use range, the U-50 series measure 11 crucial water quality parameters using a single sensor head. The U-50 series is overflowing with features that make testing groundwater and surface water as straightforward as possible.
The series is comprised of seven instrument types and a total of twenty instrument and cable variations. The impressive assortment of options can appear overwhelming. To help find the best U-50 for your application, our scientists prepared a complete overview of the features and specifications of the series.
U-50 Series Key Features

Figure 2 Multiple parameters measured
via a single sensor head.
- Multiple Sensors: Multiple sensors within a single, rugged sensor head allow for seamless measurement of 11 parameters simultaneously.
- Easy to Read, Backlit LCD: All 11 parameters are listed on the screen simultaneously.
- One-Hand Operation: The U-50 series digital control unit can be held in one hand for straightforward operation.
- Rugged: The handheld unit features a shock-resistant cover designed to withstand rough treatment in the field. The sensor head is constructed using chemical resistant materials.
- Waterproof: When the sensor cable is fitted, the U-50 series is rated to JIS level 7. Meaning water shall not enter the enclosure when it's immersed under defined conditions (immersion-resistant).
- On-screen Icons: On-screen icons such as battery power, GPS, USB and probe unit connectivity ensure ease of use.
- Automatic Calibration: An easy auto-calibration feature provides hassle free calibration of pH, conductivity, dissolved oxygen, depth and turbidity.
- User-Selectable Display Units: Selectable measurement units allow users to report data easily without manually converting data to desired units.
- Minimal Maintenance: Minimum dissolved oxygen sensor maintenance thanks to the screw-on type membrane cap.
- Replaceable Electrodes: The pH and ORP electrodes can be replaced individually – at a fraction of the price of a new sensor.
- Auto-Hold: The handheld unit features automatic hold, freezing average data values on the screen for easy verification and more time to transcribe data.
- Data Management: The unit features a USB connection for easy data transfer to a PC (USB sold separately with included software).
- GPS: GPS enabled units record latitude, longitude and other important location data with individual measurements – this is especially useful for environmental surveys.
U-50 Series Model Specifications
|
U-51 |
U-52 |
U-52G |
U-53 |
U-53G |
U-54 |
U-54G |
Cable Lengths |
|||||||
pH |
✔️ |
✔️ |
✔️ |
✔️ |
✔️ |
✔️ |
✔️ |
ORP |
✔️ |
✔️ |
✔️ |
✔️ |
✔️ |
✔️ |
✔️ |
Dissolved Oxygen |
✔️ |
✔️ |
✔️ |
✔️ |
✔️ |
✔️ |
✔️ |
Conductivity |
✔️ |
✔️ |
✔️ |
✔️ |
✔️ |
✔️ |
✔️ |
Salinity |
✔️ |
✔️ |
✔️ |
✔️ |
✔️ |
✔️ |
✔️ |
TDS |
✔️ |
✔️ |
✔️ |
✔️ |
✔️ |
✔️ |
✔️ |
Seawater Specific Gravity |
✔️ |
✔️ |
✔️ |
✔️ |
✔️ |
✔️ |
✔️ |
Temperature |
✔️ |
✔️ |
✔️ |
✔️ |
✔️ |
✔️ |
✔️ |
Turbidity (LCD) |
❌ |
✔️ |
✔️ |
❌ |
❌ |
✔️ |
✔️ |
Turbidity (Tungsten lamp) |
❌ |
❌ |
❌ |
✔️ |
✔️ |
❌ |
❌ |
Water Depth |
❌ |
❌ |
✔️ |
✔️ |
✔️ |
✔️* |
✔️* |
GPS (12 channel parallel) |
❌ |
❌ |
✔️ |
❌ |
✔️ |
❌ |
✔️ |
*Water depth only available for 10m and 30m models |
Table 1 Horiba U-50 Series Model Specifications
U-50 Series General Specifications
|
U-51 |
U-52 |
U-52G |
U-53 |
U-53G |
U-54 |
U-54G |
|
pH
|
Measurement Principle |
Glass electrode method |
||||||
Range |
pH0 to 14 |
|||||||
Resolution |
0.01pH |
|||||||
Repeatability |
±0.05pH |
|||||||
Accuracy |
±0.1pH |
|||||||
Oxidation-Reduction Potential (ORP) |
Measurement Principle |
Platinum electrode method |
||||||
Range |
-2000 mV to +2000 mV |
|||||||
Resolution |
1 mV |
|||||||
Repeatability |
±5 mV |
|||||||
Accuracy |
±15 mV |
|||||||
Dissolved Oxygen (DO)
|
Measurement Principle |
Polarographic method |
||||||
Range |
0 to 50.0 mg/L |
|||||||
Resolution |
0.01 mg/L |
|||||||
Repeatability |
±0.1 mg/L |
|||||||
Accuracy |
0 to 20 mg/L: ±0.2 mg/L 20 to 50 mg/L: ±0.5 mg/L |
|||||||
Conductivity (COND)
|
Measurement Principle |
4 AC electrode method |
||||||
Range |
0 to 10 S/m (0 to 100 mS/cm) |
|||||||
Resolution |
0.000 to 0.999 mS/cm: 0.001 mS/cm 1.00 to 9.99 mS/cm: 0.01 mS/cm 10.0 to 99.9 mS/cm: 0.1 mS/cm 0.0 to 99.9 mS/m: 0.1 mS/m 0.100 to 0.999 S/m: 0.001 S/m 1.00 to 9.99 S/m : 0.01 S/m |
|||||||
Repeatability |
±0.05% F.S. |
|||||||
Accuracy |
Approx ±1% F.S. (Median of two-point calibration) |
|||||||
Salinity |
Measurement Principle |
Conductivity conversion |
||||||
Range |
0 to 70 PPT (permillage) |
|||||||
Resolution |
0.1 PPT |
|||||||
Repeatability |
±1 PPT |
|||||||
Accuracy |
±3 PPT |
|||||||
Total Dissolved Solids (TDS)
|
Measurement Principle |
Conductivity conversion |
||||||
Range |
0 to 100 g/L |
|||||||
Resolution |
0.1% F.S. |
|||||||
Repeatability |
±2 g/L |
|||||||
Accuracy |
±5 g/L |
|||||||
Seawater Specific Gravity |
Measurement Principle |
Conductivity conversion |
||||||
Range |
0 to 50σt |
|||||||
Resolution |
0.1σt |
|||||||
Repeatability |
±2σt |
|||||||
Accuracy |
±5σt |
|||||||
Temperature |
Measurement Principle |
Thermistor method |
||||||
Range |
-10 to 55℃ |
|||||||
Resolution |
0.01°C |
|||||||
Repeatability |
±0.10℃ (at calibration point) |
|||||||
Accuracy |
JIS class B platinum thermometer sensor (±0.3+0.005 | t |) |
|||||||
Turbidity (TURB) |
Measurement Principle |
❌ |
LED light source and 30°scattering method |
Tungsten lamp source and 90°scattering method |
LED light source and 90°scattering method |
|||
Range |
❌ |
0 to 800 NTU |
0 to 1000 NTU |
0 to 1000 NTU |
||||
Resolution |
❌ |
0 to 99.9 NTU: 0.1 NTU 100 to 800 NTU: 1 NTU |
0 to 9.99 NTU: 0.01 NTU 10 to 99.9 NTU: 0.1 NTU 100 to 1000 NTU: 1 NTU |
0 to 0.99 NTU: 0.01 NTU 1 to 99.9 NTU: 0.1 NTU 100 to 1000 NTU: 1 NTU |
||||
Repeatability |
❌ |
*±5% (Reading) or ± 0.5 NTU, whichever is greater |
±3% (Reading) or ±0.1 NTU, whichever is greater |
±5% (Reading) or ± 0.5 NTU, whichever is greater |
||||
Accuracy |
❌ |
±5% (Reading) or ±1 NTU, whichever is greater |
0 to 10 NTU: ±0.5 NTU 10 to 1000 NTU: 3% (Reading) or ±1 NTU, whichever is greater |
±5% (Reading) or ±1 NTU, whichever is greater |
||||
Water Depth |
Measurement Principle |
❌ |
❌ |
Pressure method |
Pressure method, only 10m and 30m product |
|||
Range |
❌ |
❌ |
0 to 30 m |
|||||
Resolution |
❌ |
❌ |
0.05 m |
|||||
Repeatability |
❌ |
❌ |
±1% F.S |
|||||
Accuracy |
❌ |
❌ |
±0.3 m |
|||||
* Accuracy is measured by calibrating 4 points for turbidity and electrical conductivity and 2 points for all other measurements against a standard solution |
Table 2 Horiba U-50 Series General Specifications
U-50 Series Applications
The U-50 series are robust and thrive in fieldwork ground and surface water testing applications. Examples of use include;
- Measurement at drainage ditches
- Tests from wharves or marine vessels
- Measurement in marshes
- Surface water environmental surveys in oceans, lakes and rivers; and
- Groundwater analysis from an intake.
Conclusion
When it comes to water quality, the list of parameters the U-50 series does not measure is probably shorter than the list it does! The U-50 series, with its 11 critical water quality parameters, a single sensor head, intuitive software and optional PC connectivity, offers the ultimate selection of field water quality assessment tools.
For more information on the Horiba U-50 series, speak with an Instrument Choice Scientist! Call 1300 737 871 or email customer-service@instrumentchoice.com.au.
Appendix
U-50 Series Meters
U-51
- Horiba U-51 MultiParameter Water Quality Meter (2m cable) Product code: IC-U51-2M-X
- Horiba U-51 MultiParameter Water Quality Meter (10m cable) Product code: IC-U51-10M-X
U-52
- Horiba U-52 MultiParameter Water Quality Meter (2m cable) Product code: IC-U52-2M-X
- Horiba U-52 MultiParameter Water Quality Meter (10m cable) Product code: IC-U52-10M-X
- Horiba U-52 MultiParameter Water Quality Meter (30m cable) Product code: IC-U52-30M-X
U-52G
- Horiba U-52G Multiparameter Water Quality Meter with GPS (2m cable) Product code: IC-U52G-2M-X
- Horiba U-52G Multiparameter Water Quality Meter with GPS (10m cable) Product code: IC-U52G-10M-X
- Horiba U-52G Multiparameter Water Quality Meter with GPS (30m cable) Product code: IC-U52G-30M
U-53
- Horiba U-53 MultiParameter Water Quality Meter (2m cable) Product code: IC-U53-2M-X
- Horiba U-53 MultiParameter Water Quality Meter (10m cable) Product code: IC-U53-10M-X
- Horiba U-53 MultiParameter Water Quality Meter (30m cable) Product code: IC-U53-30M
U-53G
- Horiba U-53G Multiparameter Water Quality Meter with GPS (2m cable) Product code: IC-U53G-2M-X
- Horiba U-53G Multiparameter Water Quality Meter with GPS (10m cable) Product code: IC-U53G-10M-X
- Horiba U-53G Multiparameter Water Quality Meter with GPS (30m cable) Product code: IC-U53G-30M-X
U-54
- Horiba U-54 MultiParameter Water Quality Meter (2m cable, no depth sensor) Product code: IC-U54-2M-X
- Horiba U-54 MultiParameter Water Quality Meter (10m cable) Product code: IC-U54-10M-X
- Horiba U-54 MultiParameter Water Quality Meter (30m cable) Product code: IC-U54-30M-X
U-54G
- Horiba U-54G Multiparameter Water Quality Meter with GPS (2m cable, no depth sensor) Product code: IC-U54G-2M-X
- Horiba U-54G Multiparameter Water Quality Meter with GPS (10m cable) Product code: IC-U54G-10M-X
- Horiba U-54G Multiparameter Water Quality Meter with GPS (30m cable) Product code: IC-U54G-30M-X
U-50 Series Accessories
- USB Cable and Software for U-50 series Product code: IC3200174823
- Probe Guard For U50 series - IC3200167002
- Flow Cell for U-50 - IC3200156570
- Turbidity Sponge Brush - IC3200169531
- pH glass electrode #7112 - IC7112
- pH reference electrode #7210 IC-7210
- pH Liquid Junction Cap - IC3200043587
- pH filling solution #330 - IC330
- ORP electrode #7313 - IC7313
- D.O. Sensor #7543 - IC7543
- DO membrane cap, 3 pieces - IC3200170194
- D.O. filling solution #306, pack 50ml - IC3200170938
- Heavy Duty Carry Case - Medium - IC383407
- Heavy Duty Carry Case - Large - IC3200174772