- 6 -
6.4
Insert the probe into pH 7.00 buffer solution, make a quick stir, and hold still. When the reading is stabilized ( stays
on screen), short press to start 1
st
point calibration. After calibration is completed, the tester will return to
measurement mode. Icon will appear at the bottom left of the screen, indicating a successful 1
st
point pH calibration.
6.5
To calibrate 2nd point, use 4.00 pH buffer and repeat Step 6.3 to 6.4 (Do NOT turn off the tester after you finish pH 7
calibration). will display next to , indicating a successful 2-point pH calibration (low and middle points).
6.6
If necessary (target pH>8.00), calibrate 3rd point using 10.01 standard pH buffer and repeat Step 6.3 to 6.4, will
show up next to and , indicating a successful 3-point calibration (high, low, and middle points).
6.7
Notes about Calibration
1) The 1st point calibration must be 7.00 pH. Perform the 2nd and 3rd point calibrations (4.00, 10.01, 1.68, or 12.45)
immediately after the 1st point calibration is finished. Do NOT turn off the meter before you calibrate 2nd or 3rd
point. Otherwise, you will need to restart the calibration process with 7.00 pH first.
2) The pH 4.00 and 7.00 buffer solutions poured into the calibration vials can be used for up to 10 times as long as
they are not contaminated and the bottles are capped when not in use. pH 10.01 can only be used for up to 5
times as it will lose its accuracy much faster. After that, replace the buffer solutions in the calibration vials with
new ones to keep the accuracy. Keeping the freshness and cleanliness of calibration buffers is essential for
accurate pH measurement.
3) The tester can perform 1 to 3 points of automatic calibration and can recognize 5 types of pH standard solutions.
For details, please refer to the following table:
Calibration
USA Series
NIST Series
Indication icon
Recommended
1-pt
7.00 pH
6.86 pH
Accuracy ≥ 0.1 pH
2-pt
Option A
1st pt: 7.00 pH
2nd pt: 4.00 or 1.68 pH
Option A
1st pt: 6.86 pH
2nd pt: 4.01 or 1.68 pH
Range < 7.00 pH
Option B
1st pt: 7.00 pH
2nd pt: 10.01 or 12.45 pH
Option B
1st pt: 6.86 pH
2nd pt: 9.18 or 12.45 pH
Range >7.00 pH
3-pt
1st pt: 7.00 pH
2nd pt: 4.00 or 1.68 pH
3rd pt: 10.01 or 12.45 pH
1st pt: 6.86 pH
2nd pt: 4.01 or 1.68 pH
3rd pt: 9.18 pH or 12.45 pH
Range: 0 to 14.00 pH
