Portable TDS Meter

This rugged and easy to use TDS meter has a range of 0-5000 ppm (parts per million), and operates on a single 9-volt battery. A small well holds the water sample, about 5mL. Lacking an analog or a digital display, the measurement is made by holding a button down and adjusting a dial along a graduated scale until an LED illuminates. A switch on the base changes between three range multipliers: 1, 0.1, and .01, in effect, making the meter’s effective ranges 0-5000, 0-500, and 0-50, respectively.