
13. Fill a cuvette with a few drops of
a water sample
14. Insert a
[DPD No. 1] tablet
directly from the foil into the
water sample and crush the
[DPD No. 1] tablet with a stirring
rod
15. Fill the cuvette up to the 10 ml
marking with the water sample
16. Close the cuvette using the cuv‐
ette lid
17. Mix the contents of the cuvette
by tipping it back and forth, until
the tablet has dissolved
18. Position the cuvette in the
sample chamber
ð
Observe the correct posi‐
tioning of the cuvette.
19. Press the key
[ZERO/TEST]
ð
[METHOD] flashes for
approximately 3 seconds.
The display value
[A] (sum
of free chlorine plus chlorine
dioxide) appears in the dis‐
play.
20. Remove the cuvette from the
sample chamber
21. Insert a
[DPD No. 3] tablet
directly from the foil into the
same water sample and crush
the
[DPD No. 3] tablet with a
stirring rod
22. Close the cuvette using the cuv‐
ette lid
23. Mix the contents of the cuvette
by tipping it back and forth, until
the tablet has dissolved
24. Position the cuvette in the
sample chamber
ð
Observe the correct posi‐
tioning of the cuvette.
25. Switch the countdown on, see
function on’ on page 13. To do
this, press the
[!] and
[ZERO/TEST] key
ð
Wait for the 2 minutes reac‐
tion time to elapse
26. The METHOD symbol flashes
for approximately 3 seconds
ð
The display value
[C] (sum
of free chlorine plus com‐
bined chlorine plus chlorine
dioxide) appears in the dis‐
play.
27. Calculation:
n
Chlorine dioxide (mg/l) =
display value
[G] x 1.9
n
Free chlorine (mg/l) = dis‐
play value
[A] minus display
value
[G]
n
Combined chlorine (mg/l) =
display value
[C] minus dis‐
play value
[A]
Analysis methods
27