22
INTERFERENCES
Interference may be caused by:
Alkalinity: above 1,000 mg/L CaCO
3
if present as bicarbonate (HCO
3
sample pH <
8.3); above 25 mg/L CaCO
3
if present as carbonate (CO
3
2‑
, sample pH > 9.0). In
both cases, it will not reliably develop the full amount of color or it may rapidly fade
(negative error). To resolve this, neutralize the sample with diluted HCl.
Acidity: above 150 mg/L CaCO
3
. May not reliably develop the full amount of color or
it may rapidly fade (negative error). To resolve this, neutralize the sample with diluted
NaOH.
Hardness: 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. Bromine (Br
2
),
Ozone (O
3
) and Chlorine dioxide (ClO
2
): positive error.
• Press the
Read
key and the display will show a 2 minute 30 second countdown
prior to the measurement. To skip the timer press
Read
twice
.
When the timer ends
the meter will perform the reading. The instrument displays the results in
mg/L of
chlorine (Cl
2
)
.
TO
TAL CHLORINE HR
