Which device is used to measure total dissolved solids in the water?

A TDS meter is specifically designed to measure total dissolved solids in water, which consists of inorganic salts and small amounts of organic matter. This instrument typically operates by measuring the conductivity of the water, which correlates with the concentration of dissolved solids. Since dissolved solids conduct electricity, the TDS meter uses this principle to provide a reading of how much dissolved material is in the water.

While a conductivity meter can also be used to determine the level of total dissolved solids, it is important to note that the TDS meter is calibrated to provide a direct measure of TDS, often expressed in parts per million (ppm) or milligrams per liter (mg/L). This makes it a more straightforward option for specific TDS measurements compared to a broader conductivity meter.

The other devices mentioned perform different functions. A pH meter measures the acidity or alkalinity of a solution, and a salinity meter specifically measures the salt concentration in water, which does not equate directly to total dissolved solids. Therefore, a TDS meter is the most appropriate and direct tool for assessing total dissolved solids in water.