Water Quality Tester | Tap vs Bottled Water 

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TDS Water Quality Tester
HM Digital TDS-EZ Water Quality TDS Tester, 0-9990 ppm Measurement Range , 1 ppm Resolution, +/- 3% Readout Accuracy
Measurement Range: 0-9990 ppm. From 0-999 ppm, the resolution is in increments of 1ppm. From 1000 to 9990 ppm, the resolution is in increments of 10ppm, indicated by a blinking 'x10' image. Fun, translucent blue housing that's very strong and durable.
TDS-EZ meters are calibrated with a 342 ppm NaCl solution. Meters can be recalibrated with a mini-screwdriver. Includes a TDS chart sticker on the back of the meter that explains TDS values.