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6
System Mode
6.0 Analysing Samples
The Pooltest 25 provides simple, accurate and
reliable analysis of key pool, spa and other
aquatic samples. Selecting the required parameter
and performing the test are supported through on-
screen prompts and comprehensive test
instructions.
The principle of photometric testing is based on the
absorption or scattering of a measured intensity
of incident light compared to the light intensity
reaching the detector array. The light intensity is
determined as Transmittance (%T) or Absorbance
(A) and compared to calibration tables stored within
the Pooltest 25. The stored calibration tables
convert %T or A to results in a variety of units
(mg/l, ppm etc.) as defined in Section 6.6.
Calibration tables are defined by Palintest based
on the measurement of reference standards using
Palintest reagents. To achieve the best quality
results there are a small number of care points:
1 Always use the provided light cap to prevent
ambient light affecting the results.
2 Ensure Sample and Blank cuvettes are clean, dry
and inserted correctly into the sample chamber,
using the allocated orientation mark to align.
3 Always blank the instrument with untreated
sample prior to analysis.
Additional guidance is provided in Appendix 1
Photometric Testing Hints and Tips
6.1 Selecting Test Parameters
The Pooltest 25 offers a number
of choices to select the parameter to test:
Test Number Entry - use the numeric keypad
to enter the unique Test Number to directly
access any programmed calibration.
Direct Entry - use the numeric keypad to
directly access the 10 most common tests with
a single key push.
Choose a Test - the full list of test parameters is
available by selecting Choose a Test and scrolling
using the up/down keys. When the desired parameter
is highlighted, press the OK key to access the
method. Tests are presented in Test Number order.
When the required test is selected the Pooltest 25
automatically selects the correct wavelength and sets
12
additional method parameters as required.
Test method protocols are defined in detail section 8,
including the reagents and accessories that may
be required.
When a test is selected, the Pooltest 25 will display
a number of screens and options to guide the
user through the testing process, as described in
the following pages.
6.2 Dilution Factor
If selected in the System menu, the initial screen will
request the defined Dilution Factor to apply to results.
If Dilution Factor is not active this screen will not
be shown.
Results shown on the final screen have automatically
been corrected for dilution prior to display.
Corrected results will also be stored in the log.
Note: if the System Lock is applied the Dilution
Factor functionality cannot be switched on or off
from the current status until the system is unlocked.
6.3 Blanking the Pooltest 25
Blanking the photometer is a key first step in
photometric analysis, effectively removing the
potential entrained sample colour and minor amounts
of turbidity from calculation of analytical results.
To blank the photometer, prepare a Blank cuvette
using untreated sample i.e. sample that has not
been reacted with any reagents. If the sample is
to be diluted or physically treated (filtered for
example) before analysis, use the same dilution/
treatment for the Blank cuvette.
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