Combined Chlorine - eXact Micro 20 Instruction Manual

Combined Chlorine test procedure
This procedure is only valid when ran as a continuation of the eXact
CL (DPD–1 Free Chlorine). Test procedure located on the previous page.
8
6 9
10
NOTE: Standard Method (4500–Cl G, procedure for total chlorine) requires the reading to be made after 2 minutes
from the time the KI is added. For compliance testing, you must time the 2 minutes and then make your measurement.
Interfering Substance
Acidity
Alkalinity
Bromine and Bromamines, Br
Chlorine Dioxide, ClO
Copper, Cu
2+
Iodine, I
2
Manganese, oxidized (Mn
or Chromium, oxidized (Cr
Monochloramines (NH2Cl)
(applies to DPD-1 only)
Ozone, O
3
Peroxides
pH
*For best accuracy, when testing outdoors in sunlight, place cap over cell cover
REMOVE STRIP
Remove 1 eXact
from the bottle before beginning the test. Set the strip in a dry,
convenient place and recap the bottle immediately.
DIP STRIP & PRESS READ
Dip the eXact
immediately press
timer. During this time, move the strip in a gentle back and
forth motion (approx. 2 strokes per second). Remove and
discard the strip after '1' on the display disappears*. The
cursor will move across the display while the meter prepares
to measure the sample. Record the value displayed and this
value is automatically stored in the CL MENU, the result will
be saved in the app's 'HISTORY'.
(
NOTE: The Iodide added with DPD–3 will, in the presence of
Combined Chlorine or Chloramines, convert into Iodine).
PRESS READ AGAIN
Press again and the meter will count down and display the next reading. If
this reading matches the previous result, then record this as the Total Chlorine
result. This value is automatically stored in the CL MENU. After testing is
completed, rinse CELL immediately. Record the highest value the meter
displayed as your Total Chlorine result.
Interfering Levels and Treatments
If sample has acidity above 150mg/L CaCO3 test may not develop
full color. Neutralize to pH 6.0 to 7.0 with 0.5N Sodium hydroxide.
If sample has alkalinity above 200mg/L CaCO3 test may not
develop full color. Neutralize to pH 6.0 to 7.0 with 0.5N Sulfuric acid.
Color similar to free chlorine reaction at all levels.
2
Color similar to free chlorine reaction at all levels.
2
Color development is reduced above 10 ppm (mg/L).
Color similar to free chlorine reaction at all levels.
, Mn ) See AWWA procedure 4500-CL F, 1(d) for removal of interferences.
4+ 7+
)
6+
Monochloramine interferences are known to occur in free chlorine
DPD methods. This interference is dependent on temperature and
monochloramine concentration.
Color similar to free chlorine reaction at all levels.
Interference is possible.
Typical pH samples of potable water with a pH of 6.0 to 9.0 are
OK. If outside this range adjust to pH 6.0 to 7.0 using acid
(0.5N Sulfuric acid) or base (0.5N Sodium hydroxide).
Strip Micro CL (DPD–3), Part No. 486638
®
strip micro (DPD–3) into the CELL, and
®
This will start a 20 second countdown
Strip Micro
®
19