Calibration 1. Turn on pH meter 2. Immerse the electrode in pH 6.86 standard buffer solution. (under the temperature of 25°C) 3 Press the "CAL" button. Wait until the display digital is 6.86pH. Then complete pH 6.86 calibration 4 Clean the electrode with distilled water and dry it with filter paper. Immerse the electrode in pH 4.00 standard buffer solution, 5 Press "CAL" button. Wait until the digital is 4.00 pH Complete the pH 4.00 point calibration. 6 Clean electrode and dry it, put pH meter into pH 9.18 standard buffer solution. Check if reading is correct between 9.17-9.19 pH.