ST-731 Inline Turbidity Sensor (0–10NTU)

A Turbidimeter with a Condensed Range.

A robust turbidimeter that measures for NTU at a range of 0–10. Connect the sensor to our MA-WB Bluetooth® Adapter to monitor, configure, calibrate and share your collected data on the uPyxis® app!

CE Mark



The ST-731 is an inline turbidimeter designed for a wide range of turbidity monitoring in various applications. Each device is configured with a specific scale for NTU detection, ranging from 1–10NTU. This sensor is more robust and tolerant to fouling, rendering alternative turbidity sensors inferior due to particulate and air bubble challenges. The ST-731 also offers desired resolution and accuracy in high turbidity applications commonly using suspended solid meters.

Typical Applications

  • Industrial Process Water
  • Fresh, Brackish, Sea Water
  • Cooling Water
  • Raw, Influent Water
  • Wastewater Effluent
  • Surface Water
  • Storm Water



Item ST-731
Part Number 53505
Range 0-10NTU
Resolution 0.05NTU
Accuracy ±2% of Reading
Method Nephelometric Turbidity Units (NTU)
Light Source White LED
Power Supply 22-26VDC, Power Consumption – 1W
Outputs Isolated 4-20mA Analog
Isolated RS-485 Modbus Digital
Dimension 6.8in (172.7mm) L, 1.44in (36.6mm) D
Weight 170g (0.37lbs)
Installation ST-001 Inline Tee with 3/4in FNPT with Union Socket & Thread Adapters
Material UPVC
Pressure 100psi (6.9Bar)
Temperature Operation: 40-120 °F (4-49 °C)
Storage: 20-150 °F (-6-66 °C)
Cable Length 1.5m 7-Pin Bulkhead with Adapter
1.5m 7-Pin Flying Lead with Adapter
Calibration Two Point Calibration against Formazin Standard Solutions
Rating IP66
Regulation CE / RoHS
Compliance US-EPA

Support Documents

ST-730 Series User Manual V1.37

ST-730 Series Data Sheet



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