Turbidity can be estimated with equipment such as the spectrophotometer and colorimeter, which can measure the decrease in transmitted light due to blockage generated by particles. However, these measurements are not considered valid by international regulatory bodies because they do not meet the accepted definition of turbidity, and they always propose the use of the turbidity meter.
A turbidity meter is designed for field or laboratory measurements, as well as for uninterrupted monitoring through the setting of an alarm that is activated when unsafe turbidity levels are reached. Turbidimeter setup is an essential element for good turbidity measurement performance. The turbidity unit used by turbidity meters is the NTU (nephelometric turbidity unit), and they usually have a measurement range from 0 to 2000 NTU in the most sophisticated instruments. The latest technology for turbidity measurement uses a laser to measure light scattering at 90° and 360° around the sample, offering high optical accuracy, fast results and increased equipment reliability.