What is Turbidity?

Turbidity is a measurement of solid matter being suspended in water, rather than dissolved into it. If water is turbid it appears to be cloudy, so is a visual guide to water quality.

Aquaread Turbidity Sensor

Aquaread’s turbidity sensor is designed to give a measure of suspended particles in a sample of water. It achieves this by emitting infra-red light into the sample and measuring the incident light scattered at right angles from the particles in the sample.

This electrode employs a Nephelometric technique in accordance with ISO 7027, which uses Formazin as a reference standard. The Aquameter displays turbidity in Nephelometric Turbidity Units (NTU) which are nominally equivalent to Formazin Turbidity Units (FTU).


Key Features

  • Dense sapphire lenses are used on our turbidity sensor for their high clarity and scratch resistance.
  • Turbidity Measurement range: 0-3000 NTU.
  • 3-point calibration at 0, 20 and 1000NTU.
  • Internal temperature compensation.
  • Auto range scaling: 0-99.9 / 100-3000 NTU.
  • Simple to install on a wide range of Aquaprobes.
  • Easy calibration.

Our Turbidity can be installed on many of our probes, below are some examples. To see all of the probes that can house the turbidity sensor please visit the Products section.



Single parameter Aquaprobe, for use with any of our sensors.



Long-term deployment multi-parameter Aquaprobe.



The Aquasonde-2000 has 2 spare ports. They can house either 1x ISE sensor and 1x Optical sensor. Or it can house 2x ISE sensor.

Versatile sensor

The turbidity sensor can be used in the AP-LITE for a single parameter setup, where turbidity measurement is the only requirement. The sensor can also be used in all of our multiparameter Aquaprobes and Aquasondes where larger data acquisition is required.

Cost-effective solution with high performance

The turbidity sensor is designed and manufactured by Aquaread in the UK. We take every care to ensure the highest quality at an industry-leading price point.

Simple installation

Installing the turbidity sensor into an Aquaprobe is a very simple process. Simply unscrew the blanking plug from an appropriate aux socket, apply some silicon grease to the thread of the turbidity sensor (grease provided), and screw in the sensor. Full calibration is required after installation.

Simple calibration

Here at Aquaread, ease of use factors into each and every one of our products. This ethos extends to the calibration process.

Basic calibration for the sensor involves calibrating at both 0NTU and 1000NTU. Simply put the probe into the desired solution, select the correct calibration point from the calibration menu, and press OK. The Aquameter will do the rest, checking it’s in the correct solution and checking for stability prior to completing the calibration.

If your application requires high accuracy at the low end of the measurement scale, a 20NTU calibration point is also available.