User Guide

For greatest accuracy, frequent calibration of the instrument is
recommended. The instrument should be recalibrated for pH:
a) Whenever the electrode is replaced.
b) At least once a month.
c) After testing aggressive chemicals.
d) Where extreme accuracy is required.
e) Whenever the CAL-CHECK test fails (HI 9813-6 only).
PREPARATION
Pour small quantities of pH 7.01 (HI 7007) or pH 4.01 (HI 7004) or
pH 10.01 (HI 7010) solution into a clean beaker.
To obtain accurate readings, use pH 7.01 (HI 7007) if you are going
to measure neutral or close to neutral samples, pH 4.01 (HI 7004) if
you are going to measure acidic samples or pH 10.01 (HI 7010) for
alkaline measurements.
If you need to calibrate to NBS standards, use pH 6.86 (HI 7006)
instead of pH 7.01 and pH 9.18 (HI 7009) instead of pH 10.01.
PROCEDURE
• Connect the probe and switch the meter on, then press the "pH"
key to display pH measurement.
• Remove the protective cap from the probe, rinse and immerse it
in the buffer and stir gently. Wait a couple of minutes for the
reading to stabilize.
• Take the temperature of the buffer solution,
e.g. 10.0°C, as follow:
for HI 9813, with a ChecktempC (or another
accurate thermometer);
for HI 9813-5 and HI 9813-6, select the
°C mode and read the displayed value.
• Adjust the pH calibration knob until the LCD
shows the pH value at the above tempera-
ture (see the pH versus temperature chart).
• The pH calibration is now complete.
pH CALIBRATION