One button (SHIFT) switch the 4 display modes: TDS - ppm & °C, EC - µs/cm & °C, TDS - ppm & °F, EC - µs/cm & °F. - TDS: 0 - 9999ppm (Parts per million). - Conductivity (EC): 0 - 9999µs/cm. a. Dissolve pH buffer powder in 250ml of distilled water.
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