We are offering tds meter. ideal for all water purification applications, wastewater regulation, aquaculture, hydroponics, and colloidal silver. Perfect for both consumer or commercial use. Carry one in your pocket or toolbox at all times! specifications tds range: 0 - 9990 ppm (mgl) temp. Range: 0 - 80 degrees celsius resolution: 1 ppm, 1 degree celsius (also available in 10 ppm) accuracy: +- 2% conversion factor: nacl (avg. 0.5) atc: built-in sensor for automatic temperature compensation of 1 to 50 degrees celsius (33 to 122 degrees fahrenheit)