User Manual

5
4.1.6 To calibrate 2
nd
point, use 4.00 pH buffer and repeat Step 5.1.3 to 5.1.5 (Do NOT turn off the tester
after you finish pH 7 calibration). will display next to , indicating a successful 2-point
calibration (low and middle points).
4.1.7 If necessary (target pH>8.00), calibrate 3rd point using 10.01 standard pH buffer and repeat Step
5.1.3 to 5.1.5, will show up next to and , indicating a successful 3-point calibration
(high, low, and middle points).
4.2 Notes about Calibration
a) The 1
st
point calibration must be 7.00 pH. Perform the 2
nd
and 3
rd
point calibrations (4.00, 10.01, 1.68,
or 12.45) immediately after the 1
st
point calibration is finished. Do NOT turn off the meter before you
calibrate 2
nd
or 3
rd
point. Otherwise, you will need to restart the calibration process with 7.00 pH first.
b) 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.
c) 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 requirement
≥ 0.1 pH
2-pt
Option A
1
st
pt: 7.00 pH
2
nd
pt: 4.00 pH or
1.68 pH
Option A
1
st
pt: 6.86 pH
2
nd
pt: 4.01 pH or
1.68 pH
Range < 7.00 pH
Option B
1
st
pt: 7.00 pH
2
nd
pt: 10.01 pH or
12.45 pH
Option B
1
st
pt: 6.86 pH
2
nd
pt: 9.18 pH or
12.45 pH
Range >7.00 pH
3-pt
1
st
pt: 7.00 pH
2
nd
pt: 4.00 or 1.68 pH
3
rd
pt: 10.01 or 12.45 pH
1
st
pt: 6.86 pH
2
nd
pt: 4.01 or 1.68 pH
3
rd
pt: 9.18 pH or 12.45 pH
Range: 0 to 14.00 pH