What is used to measure total dissolved solids and temperature?

The Ultrameter is specifically designed to measure various water quality parameters, including total dissolved solids (TDS) and temperature. This device utilizes conductivity to quantify the concentration of dissolved solids in a solution, providing accurate readings essential for water quality assessments.

In contrast, the other instruments serve different functions: a thermometer measures temperature alone, a voltmeter assesses electrical potential difference but is not equipped for water quality parameters, and a multimeter can measure multiple electrical quantities but typically does not measure TDS directly. Therefore, the Ultrameter's specialized capabilities make it the appropriate choice for this particular measurement task.