
13
Sample cells (Note 2)
•Take care when handling sample cells to prevent them from becoming scratched.
•Wipe off dirt from sample cells beforehand.
•Use the same sample cell for zero-point calibration and measurement.
•If the outside of a sample cell is wet, thoroughly wipe off moisture on the cell.
•Before storing sample cells, clean them with deionized water after use. (Note 3)
Measurement
•When adding powder reagent to the test water to color it, be sure to perform
measurement promptly, as the color darkens with time.
Note 1: If the temperature of the test water deviates considerably from 20 °C, perform user calibration. The
correct concentration cannot be displayed without performing user calibration.
Note 2: The body of sample cells is made of polyethylene terephthalate (PET) and their caps are made of
polypropylene (PP). If you leave a coloring reagent in a sample cell for a long time (one day or longer),
the cell may become stained. Clean the sample cells as soon as possible after measurements are
finished.
Note 3: Residual chlorine remaining in the sample cell might cause measurement error. Thoroughly clean the
cell before storage. If it is difficult to obtain deionized water, clean the cell thoroughly with tap water
before storage, and clean it with test water a few times before measurement.
The cell should be used in a temperature range between -20 °C and +50 °C. When using a drier after
cleaning it, do not dry at a temperature over 50 °C or the sample cell may get deformed.
Causes preventing normal measurement values from being
obtained and corrective actions
Problem Cause Corrective Action
Measurement
values are
slightly low.
Water from an
infrequently used
hydrant was measured.
Take a new sample and measure again after flushing
water through the hydrant for a while.
Water left for a while
after sampling was
measured.
The concentration might have changed due to
evaporation of chlorine. Sample the water again.
Your hand came into
contact with the test
water.
Free residual chlorine might have been used up.
Sample the water again.
Apparatus used was
dirty.
Thoroughly rinse and clean the apparatus to use with
test water.
The chlorine
concentration was too
high.
When test water of chlorine concentration of 15 mg/L
or higher is colored using a powder reagent, the
water turns colorless or a light reddish purple and 0 or
a value lower than the actual value is displayed for
the measurement value. In this case, dilute the test
water with purified water before measurement.
This product cannot measure chlorine concentrations
of 2.00 mg/L or higher. To measure test water
containing chlorine of 2.00 mg/L of or more, please
use the AQ-202P (Residual Chlorine
(High-Concentration), polyethylene terephthalate
(PET) sample cell body) sold separately.
The test water contains
coexistent substances
that affect measurement.
Remove coexistent substances that affect
measurement. In particular, measurement values
become slightly low if the test water contains nitrite
ions or ferrous ions.
Continued on the next page