Digital TDS Meter for Water Quality Testing - Accurate ppm Measurement for Drinking Water, Aquariums, and Hydroponics | Portable Tester for Home, Lab, and Outdoor Use

A TDS Meter indicates the  (TDS) of a , i.e. the concentration of dissolved solids in it. Since dissolved  solids such as  and  increase the  of a solution, a TDS meter measures the conductivity of the solution and estimates the TDS from that.

Dissolved organic solids such as sugar and microscopic solid particles such as colloids, do not significantly affect the conductivity of a solution so a TDS meter does not include them in its reading.