Aquameter
™
Series Instruction Manual
10401-00188 Rev M
15.6. Calibrating the Turbidity 1000 NTU Point
Remove the Probe from the calibration bottle, rinse thoroughly in fresh water (if using
RapidCal solution), shake off any excess and dry the outer sleeve with a soft cloth.
Gently invert,
do not shake
,
a bottle of
StablCal
®
Standard 1000 NTU Stabilised
Formazin Turbidity Standard
solution (manufactured by the
HACH Company
and
available from most lab supply companies) several times to thoroughly mix.
Formazin Turbidity Standard is hazardous to your health. Be sure to handle with care
and to read and comply with all health and safety advice.
Fill a 300mL Turbidity calibration bottle with the solution and drop the Probe in all the way.
Again, bang the Probe against the pad in the bottom of the bottle several times in order to
remove any air bubbles that may be clinging to the Turbidity electrodes.
Follow the procedure detailed above for Zero point calibration as far as step 6, then select
1000. Wait while the Meter stabilises and calibrates.
When the ‘Calibrating 100%’ screen (shown above) is displayed, press the
OK
key.
15.7. Verifying Turbidity 1000 NTU Point Calibration
Due to the fact that debris and air bubbles can adversely affect Turbidity calibration, it is
essential to verify calibration has been properly achieved. To do this, follow calibration with
this procedure.
1.
Remove the probe from the calibration bottle, shake it off, then reinsert. Bang
the probe to remove any air bubbles.
2.
Press the
ESC
key repeatedly to get back to the main screen.
3.
Wait until the temperature and TURB readings are stable, then check that the
TURB reading is between 990 NTU and 1010 NTU (this represents 1% of the
high scale).
4.
If the reading is outside these limits, recalibrate, this time leaving more time
for stabilisation.
If you can not successfully verify the TURB calibration after several attempts, replace the
1000 NTU Turbidity Standard. If the problem persists, strip the probe down as described
below under Lens Maintenance and thoroughly clean the Turbidity electrode lenses.
Turbidity calibration is now complete.
15.8. Errors During Calibration
If a problem occurs during calibration, an error message will be displayed. Refer to
in section 10 for error message handling.
15.9. Recognising the Turbidity Electrodes
The two Turbidity electrodes can be distinguished by their 4mm diameter polished lenses.
The Turbidity Receiver electrode is the shortest of the electrodes and its flat lens faces
towards the open end of the Probe. The Turbidity Transmitter electrode is directly opposite
the Receiver and has a dome shaped, side mounted lens that points towards the centre of
the Probe (see
Identifying The Individual Electrodes
in section 12).
© 2011 Aquaread Ltd.
www.aquaread.co.uk
Page 42 of 64
