Review on TDS water quality tester - TDS water hardness meter (portable digital salt meter for water analysis) by Dorota Szymanik (Dor ᠌

As I understand it, the main parameter measured by this device is the amount of suspension per unit volume. But if you are not blind, then it is already visible. This is not an accurate device at all. For example, you add a bag of tea to a glass of water from a well (you already know that there is clean and drinkable water) and lo and behold, the device shows that you can’t drink it. In short, this is a questionable device.