3
Photometer 7500 BT
22
Where alternative units of expression for results
are available the
▲▼
symbols will be displayed
next to the current result units. Use the up/down
arrows to change the units of expression as
required. Values are modified automatically.
Results stored in the log will be in the units
selected on screen, changing the chemical species
will add an entry to the log showing the updated
result and species parameter selected.
Follow-on Tests
A number of photometric methods have additional
optional methods that can be applied, known as
Follow-on Tests e.g. Phot 008 Total Chlorine follows
Phot 007 Free Chlorine. Follow-on methods are
usually either based on further reagent addition to
the sample just measured for sequential parameters
or used to correct for potential/known interferences.
Follow-on tests are clearly defined in the Palintest
Phot Book and, if available, are accessed via the
Follow-on
option located at the right hand side
of the options.
To access the Follow-on test, highlight Follow-on
and press OK. The next method is automatically
loaded and operated in the usual manner.
NOTE:
if no viable result is produced during the first
stage of a sequential test method, the
Follow-on
option will be automatically removed.
For correction methods, the data log will store
the corrected result automatically along with all
other results in the sequence.
All Follow-on methods have unique allocated Phot
Numbers but not all can be directly accessed.
Follow-on methods that cannot be directly
accessed are not listed in the
Choose a Test
list
for Hotkey Entry but will be available following
a viable result in the initial test stage.
3.6 7500 Test Methods
Fluoride
Range:
0-1.5mg/l (ppm) F
Colour change:
Colourless - Red/Yellow
1
Fill test cuvette with sample to the 10ml mark.
2
Add
one Fluoride No 1
tablet,
crush and mix to dissolve.
3
Add
one Fluoride No 2
tablet,
crush and mix to dissolve.
4 Stand for 5 minutes
.
5
Take photometer reading.
Chlorine-Free
Range:
0-5.00mg/l (ppm) Cl
2
Colour change:
Colourless - Purple/Red
1
Rinse test cuvette with sample leaving
two or three drops in the tube.
2
Add
one DPD 1
tablet, crush tablet and then
fill the test tube with sample to the 10ml mark.
Mix to dissolve tablet fully and ensure no
particles remain.
3 Take photometer reading immediately
.
The result may drift on standing.
4
Retain test solution if the Total Chlorine
Follow-On Test is required.
