User Manual

34 35
Reinsert the cuvette into the instrument.
Press Read to start the reading. The instrument displays the results in mg/L of free chlorine.
INTERFERENCES
Interference may be caused by: Bromine, Iodine, Ozone, Oxidized forms of Chromium and Manganese.
In case of water with hardness greater than 500 mg/L CaCO
3
, shake the sample for approximately
2 minutes after adding the powder reagent.
In case of water with alkalinity greater than 250 mg/L CaCO
3
or acidity greater than 150 mg/L CaCO
3
,
the color of the sample may develop only partially, or may rapidly fade. To resolve this, neutralize the
sample with diluted HCl or NaOH.
Free ChlorineFree Chlorine
Press the Zero key. The meter will show “-0.0-” when the meter is zeroed and ready for measurement.
Remove the cuvette.
Powder reagents procedure
Add the content of one packet of HI 93701 DPD reagent. Replace
the cap and shake gently for 20 seconds (or 2 minutes for
seawater analysis).
Reinsert the cuvette into the instrument.
Press Timer and the display will show the countdown prior to the measurement or, alternatively, wait
for 1 minute and press Read. When the timer ends the meter will perform the reading. The instrument
displays the results in mg/L of free chlorine.
Liquid reagents procedure
To an empty cuvette add 3 drops of HI 93701A-F DPD1
indicator and 3 drops of HI 93701B-F DPD1 buffer. Swirl
gently to mix, and immediately add 10 mL of unreacted
sample. Replace the cap and shake gently again.
x 3
x 3