Hanna Instruments HI 9321 - Manual (Page 10)

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In order to take accurate pH measurements, make sure that the
instrument has been calibrated before use (see page 12).
For more accurate results, it is recommended that the electrode is
rinsed thoroughly with a liberal amount of the sample to be
measured.
The pH reading is directly affected by temperature. In order for the
meter to measure the pH accurately, temperature must be taken into
consideration. A perfect equilibrium between the pH electrode and the
sample can take up to 15 minutes.
To use the Automatic Temperature Compensation feature, sub-
merge the HI 7669/2W temperature probe into the sample as close
to the electrode as possible and wait for a couple of minutes.
If the temperature of the sample is known or tests are always
performed at the same temperature you can simply manually
compensate for it. For this purpose the temperature probe must be
disconnected.
The display will then show the default tem-
perature of 25°C or the last recorded
temperature reading with the "°C" symbol
blinking.
Note the temperature of the sample using a
ChecktempC or an accurate reference ther-
mometer.
The temperature can now be adjusted with
the
↑↑↑↑↑
°C and
↓↓↓↓↓
°C keys.
If the temperature probe is connected to the
meter, the secondary LCD will display the
measured temperature and the "°C" indicator
will not blink. In this case, pressing
↑↑↑↑↑
°C or
↓↓↓↓↓
°C will not alter the temperature reading.
If measurements are taken in different samples successively, it is
recommended that the electrode (and the temperature probe) be
rinsed thoroughly with deionized, distilled or in the absence of both,
tap water and then blot dry between each measurement.
°C
°C
pH
°C
°C °C