Chematest 30
General Information
A-96.730.101 / 151118
7
2.3. Notes on Individual Methods
2.3.1
Free chlorine
When free chlorine is determined in the presence of cyanuric acid,
two forms of chlorine are measured: free chlorine and chlorine
bound to cyanuric acid. To determine the disinfection capacity of
the water, the concentration of cyanuric acid must also be mea
-
sured and the result of the chlorine determination must be correct
-
ed as follows:
2.3.2
Combined chlorine
The method catalogue of the Chematest 30 contains two options
for measuring combined chlorine: with one cuvette or with two cu
-
vettes. Apart from the fact that one or two cuvettes are used, the
two methods are identical.
Measuring with only one cuvette is faster and requires less re
-
agents. However, some standards require measurement with two
cuvettes. The selection of the method should be based on the site-
specific requirements.
2.3.3
Ozone
Ozone decomposes in a very short time and is usually only present
in traces. It is essential to rinse the cuvette three times with the
ozone-containing water before taking the sample. After sampling,
carry out the further steps as quickly as possible, but work meticu
-
lously.
Cyanuric acid
20 mg/l
30 mg/l
50 mg/l
70 mg/l
Contribution of free
chlorine to the mea
-
sured value
50%
43%
26%
19%
