36
• Remove the cuvet.
• Add the content of one packet
of HI 93701 DPD reagent. Re-
place the cap and shake gently
for 20 seconds (or 2 minutes in
case of seawater analysis).
• Wait for a minute to allow the
undissolved reagent to precipitate
and reinsert the cuvet into the
instrument.
• Press READ DIRECT and the display will show “SIP” during
measurement.
• The instrument directly displays concentration in mg/L of free
chlorine on the Liquid Crystal Display.
INTERFERENCES
Interference may be caused by: Bromine, Iodine, Ozone, Oxidized
forms of Chromium and Manganese.
Alkalinity above 250 mg/L or acidity above 150 mg/L will not
reliably develop the full amount of color or it may rapidly fade. To
resolve this, neutralize the sample with diluted HCl or NaOH.
In case of water with hardness greater than 1000 mg/L CaCO
3
,
shake the sample for approximately 1 minute after adding the
powder reagent.
Free Chlorine HR
