The SmartGarden3 turbidity sensor can measure the turbidity of the water (the number of suspended particles).
We seal the sensor before you receive it so you can use it under the water in the Hydroponics kit immediately.
Here is the assembly manual for adding this to the SmartGarden3 Hydroponics System.
Hydroponics Turbidity and pH Sensor Assembly Manual
The optical sensor of this module can measure the density of turbid water and the concentration of extraneous matter using the refraction of wavelength between photo transistor and diode. By using an optical transistor and optical diodes, an optical sensor measures the amount of light coming from the source of the light to the light receiver, in order to calculate turbidity of water.