YSI 900 Chlorine Colorimeter - Manual (Page 10)

10
Methods
!
Zero
Test
Zero
Test
CL 10
Tablet Powder
CL 10
Tablet Powder
0.0.0
Tablet Powder
CL 10
Tablet Powder
RESULT
Tablet Powder
RESULT
Tablet Powder
Chlorine Hr with DpD tablet: 0.1 – 10 mg/l
a) Free Chlorine
Fill a clean vial (24 mm Ø) with
10 ml of the water sample and perform zero
calibration (see “Operation”).
Remove the vial from the sample chamber and
empty it, leaving a few drops
remaining in the vial.
Add
one DpD no. 1 Hr tablet straight from the foil to the water sample and crush
the tablet using a clean stirring rod.
Add the water sample to the 10 ml mark.
Close the vial tightly with the cap and swirl gently several times until the tablet is
dissolved.
Place the vial in the sample chamber making sure that the marks are aligned.
Press the [ZERO/TEST] key.
The method symbol flashes for approx. 3 seconds.
The result is shown in the display in mg/l free Chlorine.
b) total Chlorine
Add one DpD no. 3 Hr tablet straight from the foil to the same water sample and
crush the tablet using a clean stirring rod.
Close the vial tightly with the cap and swirl gently several times until the tablet is
dissolved.
Place the vial in the sample chamber making sure that the marks are aligned.
Wait for a reaction period of 2 minutes.
(Countdown can be activated, see page 7)
The method symbol flashes for approx. 3 seconds.
The result is shown in the display in mg/l total Chlorine.
c) Combined Chlorine
combined Chlorine = total Chlorine – free Chlorine
Tolerances:
0 – 2 mg/l: ± 0.1 mg/l
> 2 – 4 mg/l: ± 0.3 mg/l
> 4 – 8 mg/l: ± 0.4 mg/l
> 8 – 10 mg/l: ± 0.5 mg/l