TDS meter is a convenient digital tool to check water quality. TDS = Total Dissolved Solids, which is any salt, metal or mineral in water. With the push of a button, the TDS meter can tell you the water purity level, which will be displayed on the screen in ppm (parts per million). Widely be used for all water quality testing, water purification, aquaculture, hydroponics, colloidal silver, water treatment and more. It’s a must-have handy tool for household, laboratory & other places, testing for tap water, aquarium water, filtered water, well water, refrigerated water, etc.