METTLER TOLEDO offers two different types of turbidity sensor.
Forward scattered light/absorption: Turbidity sensors with this technology (e.g. METTLER TOLEDO's InPro 8300 RAMS series) are designed for applications with low to medium turbidity levels. Color measurement (yellowness) is also available in the InPro 8300 RAMS. These are common for phase separation applications.
Backscattered light: These turbidity sensors (e.g. METTLER TOLEDO's InPro 8050, InPro 8100 and InPro 8200) are designed for samples with a high particle concentration of up to 250 g/l suspended solids. Depending on the application, the METTLER TOLEDO in-line turbidity sensors are available in both stainless steel and a polysulfone body for pharmaceutical and wastewater use respectively.