Hanna Instruments HI 99121 User Manual

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"7.01" (or "6.86") - "OK 1", and an audible signal is produced.
After 1 second, the meter automatically returns to the normal
measuring mode.

Note: It is always recommended to carry out a two-point calibra-

tion for better accuracy.

• For a two-point calibration, place the probe in pH 7.01 (or pH

6.86) buffer. After the calibration point has been accepted,
the “pH 4.01 USE” message appears. The message is held
for 12 seconds, unless a valid buffer is recognized. If no valid
buffer is recognized, then the WRNG message is shown. If a
valid buffer (pH 4.01, pH 10.01 or pH 9.18) is detected, then
the meter completes the calibration procedure. When the
buffer is accepted, the LCD shows the accepted value with
the “OK 2” message on the secondary display. The meter
then returns to the normal measuring mode.

Note: When the calibration is completed, the CAL tag is turned on.
To quit calibration and to reset to the default values
• After entering the calibration mode and before the first point is ac-

cepted, it is possible to quit the procedure and return to the last
calibration data by pressing ON/OFF/MODE. The secondary LCD
displays ESC for 1 sec. and the meter returns to normal mode.

• To reset to the default values and clear a previous calibration,

press the SET/HOLD button after entering the calibration mode
and before the first point is accepted.
The secondary LCD displays CLR for 1 sec, the meter resets to the
default calibration and the “CAL” tag on the LCD disappears.

Setup mode allows to select the temperature unit and the pH buffer
set. To enter the Setup mode, press & hold ON/OFF/MODE until
CAL on the secondary display is replaced by TEMP and the
current temperature unit (E.g. TEMP °C). Then:
• for °C/°F selection, use the SET/HOLD button. After the tem-

perature unit has been selected, press ON/OFF/MODE to
enter the buffer set selection mode; press ON/OFF/MODE
twice to return to the normal measuring mode.

• to change the calibration buffer set, after setting the tempera-

ture unit, the meter will show the current buffer set: “pH 7.01
BUFF” (for 4.01/7.01/10.01) or “pH 6.86 BUFF” (for 4.01/
6.86/9.18). Change the set with the SET/HOLD button, then
press ON/OFF/MODE to return to normal mode.

The meter displays the remaining battery percentage when
turned on. When the level is below 5%, the

- +

symbol on the

bottom left of the LCD blinks to indicate a low battery condition.
If the battery level is low enough to cause erroneous readings,
the Battery Error Prevention System (BEPS) turns the meter off.
Unscrew the 4 screws located on the back of the meter and
carefully replace the 3 AA batteries located in the battery com-
partment, while paying attention to their polarity. Reattach the
back making sure that the gasket is in place and tighten the 4
screws to ensure a watertight seal.

METER SETUP

BATTERY REPLACEMENT

ELECTRODE CLEANING

A frequent cleaning of the pH electrode is strongly recommended to
ensure correct calibration and reliable readings.

Hanna Instruments has developed a complete series of cleaning
solutions dedicated to specific applications and kind of dirty that has
to be removed from the electrode.

In soil measurements you can choose between two different solu-
tions accordingly to the type of tested soil:

• HI 700663 is indicated for inorganic soil deposits (as minerals,

limestone, adsorbed clays)

• HI 700664 is specific for organic soil deposits (humus)

If cleaning is performed frequently, soak the electrode in the specific
solution for a few minutes.

If the electrode has not be cleaned for a while, for a complete
removal of soil deposits, proceed as follows:
• wipe the electrode body (not bulb) with paper or soft tissue
• rub the reference with abrasive paper
• immerse into cleaning solution for at least 15 minutes.