Use the two fingers to press the " ▲ Button " ( 3-5,
Fig 1 ) and " ▼ Button " ( 3-6, Fig. 1 ) at the
same time. Until Display will show the following screen
then release the both fingers.
PH
CAL
6)
Press the " ▲ Button " ( 3-5, Fig. 1 ) or " ▼ Button "
( 3-6, Fig. 1 ) once in sequence to select the following
screen.
a For pH 4.00 calibration
4.00
CAL
b For pH 7.00 calibration
7.00
CAL
c For pH 10.00 calibration
10.00
CAL
d Clear the existing calibration data
CLr
CAL
17