Which device is used to measure NTU's (Nephelometric Turbidity Units)?

The device used to measure NTU's, or Nephelometric Turbidity Units, is a nephelometer. This instrument operates by passing a light beam through a sample of water and measuring the amount of light that is scattered by particles suspended in the water. The degree of scattering is indicative of the turbidity level, which is an important parameter in water quality testing.

Turbidity is a key indicator of the clarity of water and can affect the health of aquatic environments. It can also influence processes in water treatment systems, as higher turbidity levels may indicate the presence of pollutants, bacteria, or other harmful substances. Therefore, using a nephelometer provides precise and reliable measurements vital for ensuring water meets safety standards and is suitable for consumption or use.

In contrast, the other devices mentioned serve distinct purposes: a pH meter measures acidity or alkalinity, a conductivity meter assesses the ability of water to conduct electricity (which relates to ion concentration), and a hydrometer determines the specific gravity of liquids. Each of these instruments is crucial in their respective applications but does not measure turbidity.