The Hanna Instruments TDS 1 is a 0 to 999 ppm (mg/L) TDS Tester for water conditioning. Water contains a variety of minerals and salts such as carbonates, bicarbonates, chlorides and nitrate. The Hanna Instruments TDS1 is the parameter that measures the total sum of all of these compounds. + The Hanna Instruments TDS 1 is a simple and affordable tester for TDS measurements. Due to its internal sensor, TDS measurements are automatically compensated for temperature variations. Calibration can be performed in one point with a trimmer. + The Hanna Instruments TDS 1 is supplied with a cap that protects the probe when it is not in use. Batteries can be easily replaced. Light and small, Hanna Instruments TDS 1 is an ideal pocket meter to perform quick TDS measurements.