Turbidity Meter, Turbidimeter - TurbSense®

The turbidity meter from Pi is the world’s only probe based turbidity meter with a resolution of 0.001NTU. It achieves this through its patented technology that complies with international standard ISO 7027 at the same time that it sets the standard in stability and low maintenance. The patent relates to the measurement of the emitted light as well as the received light allowing the TurbSense® turbidimeter to vary the light output. Doing this allows for the mathematical correction for zero, zero drift, aging optics and fouling windows. The TurbSense® self-calibrates every time it takes a reading and therefore it is only necessary to check the calibration every several months.

TurbSense® Turbidimeter Capabilities

Ranging from 0.01 NTU to 1000 NTU with a resolution in the 0-10 NTU range of 0.001, the TurbSense® online turbidity meter provides:

  • Excellent resolution
  • Single point calibration
  • The simplicity of a probe
  • Great value for money
  • Long term reliability
  • Autoclean capability

TurbSense® Turbidimeter 3D Model

If you have any questions or would like to find out more about TurbSense® get in touch with one of our technical experts.

Focus On

Focus Ons are a series of short articles distributed by email providing technical information regarding instrumentation, process measurement in potable, waste, process and pool waters. If you would like to join the mailing list, please contact us.


Turbidity uses nephelometric turbidity units (NTU) and is a measurement of the ‘cloudiness’ of a water sample. Suspended solids describes the mass of solid particles suspended in a given volume of water and is most commonly expressed in mg/l. The two measurements are related, but the conversion between them will depend upon the properties of the suspended material.

TurbSense® can be calibrated in two ways. Firstly, a separate device (commonly a hand held, portable turbidimeter) can be used to analyze the same sample as the TurbSense® and this value can be used to perform the calibration. Secondly, the sensor can be placed into a sample of known turbidity (such as a 25 NTU standard solution), and the TurbSense® system can calibrate itself based on this. Because of the unique way in which the sensor performs the calibration, only a single standard is required and a zero point calibration isn’t needed (patentented feature).

Compared to glass or quartz, sapphire is much tougher and resistant to scratches. Additionally, because it is much stronger the window can be thinner, which improves the quality of optical transmission.

50°C or 120°F. This is because the electronics inside the TurbSense® will start to degrade in temperatures higher than that.

Yes, but there are factors end users should consider because the reliable operation of the sensor depends upon a powerful light source and sensitive optics. Reflections from walls and bends in pipes can cause problems in accuracy, so the turbidity of the process stream, the diameter of the pipe and the material used will need to be taken into account.

Larger diameter pipes and those made of less reflective materials are better; additionally, the higher the turbidity the more likely pipe insertion will be effective. At >200NTU, putting a TurbSense® into a pipe shouldn’t be a problem.

Many users who purchase TurbSense® use our Autoclean option to ensure optimum performance; pressurized water cleans the sensor head on a user designed schedule which greatly reduces maintenance times. Ideally the sensor should not be placed in direct sunlight as this can affect the reliability of the sensor.
The specially designed flow chamber provides the ideal environment for the TurbSense®. It removes entrained bubbles, is sealed against ambient light and its black polypropylene construction eliminates internal reflections. It also allows the sensor to be incorporated into a sample line along with other sensors. For more details please refer to the Technical Note Bubbles in Turbidity Measurements.


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