Turbidity is the measure of the intensity of light transmitted through a liquid sample. Due to the presence of suspended matter, such as clay particles, microscopic organisms, organic matter, and colloidal particles, water can become turbid. Hence, turbidity is a physical property that indicates the concentration of scattering particles in water and consequenly is an important water quality parameter. It is measured optically as a light-scattering property of water. Field meters use the nephelometric method to measure turbidity and read it in nephelometric turbidity units (NTUs), or alternatively in FNU and FTU (Formazin Nephelometric Units and Formazin Turbidity Unit, respectively). Hach's newest instruments provide reliable and accurate results that give you the confidence you expect from your turbidity measurements. Hach has engineered a breakthrough lab turbidity meter TU52 for drinking water and other clean water applications, and TL23 for high turbidity range applications.