(1) Dissolve the pH buffer powder in 250ml of distilled water.
(2) Wash the electrode with distilled water and wipe it dry, then put it into the 6.86 solution, press and hold the CAL key for 5 seconds, the number displayed is 6.86 pH, and the calibration pH 6.86 is complete.
(3) Wash the electrode with distilled water and dry it. Then put it into the 4.01 solution, press and hold the CAL button for 5 seconds, then release it, press the CAL button to enter the 4.01 calibration mode, and wait for the screen to stop flashing to complete the calibration.
(4) Wash the electrode with distilled water and dry it. Then place it in the 9.18 solution, hold down the CAL button for 5 seconds, then release it, press the CAL button to enter the 9.18 calibration mode and wait for the screen to stop flashing to complete the process. calibration. Rinse the electrode with distilled water and dry it, then follow the steps above to calibrate other products.