Hanna Instruments HI 2222 User Manual

Page 10

TWO-POINT CALIBRATION

TWO-POINT CALIBRATION
For most applications it is recommended that pH 7.01 or 6.86 buffers be
used as the first calibration point and pH 3.00 (for acidic samples) or pH
9.18/10.01 (for alkaline samples) as the second calibration point.
Note: The pH 12.45 buffer is not for general measurement; use only if

the sample is very alkaline to avoid sodium error.

• Submerse the pH electrode and the temperature probe approximately

3 cm (1¼”) into a buffer solution and stir gently. The temperature
probe should be close to the pH electrode.

• Press the CAL key. “CAL” and “pH” tags will be on, and the

“CLEAR CAL if new electrode” tag will blink.

• Press the CLR key if you are using a new electrode or want to clear

the calibration history. The instrument will display the “donE”
message for a few seconds.

• Press the CAL key, or wait a few seconds to continue.

It is very important to clear the calibration history when a new electrode
is used because all error and warning messages that appear during
calibration depend on the calibration history.

Note: • The “CLEAR CAL if new electrode” will only appear if the

instrument has been previously calibrated.

• The “CAL”, “pH” and “BUFFER” tags will appear and the

“7.01” buffer will be displayed on the secondary LCD.

• Press the ARROW keys to select a different buffer value, if

necessary.

• The “ ” tag will blink until the reading has stabilized.

CLEAR CAL if new electrode

CAL