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When accessing the test method the Pooltest 25
will request the user to Insert Blank.
Insert the Blank cuvette and press OK.
The Pooltest 25 will determine the absorbance
due to the sample colour at all wavelengths
simultaneously and store in temporary memory
for use in analysis.
Upon successful blanking the Pooltest 25 will
automatically move to the Insert sample stage of
the analytical method.
If the sample is too highly coloured to support
effective blanking and subsequent analysis the error
message "Error 9 is caused by the blank cuvette being
too dark. Check the correct cuvette is being used".
Analysing Samples
Ensure the blank cuvette is being used, not the
sample plus reagent cuvette. Sample colour can
be reduced by dilution with clean water; the
dilution selected should take account of the
expected concentration of parameter under test.
Blank results are stored in the temporary memory
of the Pooltest 25 and will be used for all
subsequent tests until:
• The instrument is powered down (temporary
memory is lost/deleted)
• A new Blank reading is taken - this option is
available on accessing any subsequent test at
the base of the screen. Repeat the blanking
process if the sample changes significantly
or a new sample is under test
• Some tests use a reversed blanking process
where a coloured blank cuvette may be required.
When changing between standard tests and
'reverse blank' test, a new blank will be
requested by the Pooltest 25.
If the blank value generated in this step is not
detectable an error message will be displayed
"Error 7 is caused by too much ambient light. Try
using the light cover provided with the instrument".
See Appendix 1 Photometric Testing Hints and
Tips for more advice regarding effective blanking.
6.4 Reading Results with
the Pooltest 25
Assuming a suitable blank has been recorded,
the next step of the photometric analysis process
is to carry out the reading step.
Prepare a Sample cuvette following the method
instructions provided in Chapter 8.
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