... that you drink. The higher the TDS levels in the water, the greater the probability of harmful ... 0-9990ppm. From 0-999ppm, the resolution is in increments of 1ppm. From 1,000 to 9,990ppm ... , the resolution is in increments of 10ppm, indicated by a blinking 'x10' ... - 9990ppm (mg/L) Accuracy: +/- 2% ATC: Built-in sensor for Automatic Temperature Compensation of 1 to 50 degrees Celsius ...