OPERATIONAL GUIDE
OPERATIONAL GUIDE
OPERATIONAL GUIDE
OPERATIONAL GUIDE
OPERATIONAL GUIDE
MEASUREMENT PROCEDURE
• Turn the meter on by pressing ON/OFF.
• When the LCD displays "- - -", it is
ready.
• Fill a graduated beaker to the
50 mL mark with the sample.
• Add 0.5 mL of HI 93720A Calcium
indicator solution, then swirl to mix.
• Add 0.5 mL of HI 93720B Alkali
solution for Calcium, then swirl to
mix.
• Fill two cuvets up to 1.5 cm (¾")
below the rim with 10 mL of
sample each.
• Add 1 drop of HI 93720C EGTA
solution to one cuvet, replace the
cap and swirl the solution. This is
the blank.
• Place the blank into the
holder and ensure that the
notch on the cap is posi-
tioned securely into the
groove.
• Press ZERO and "SIP" will
appear on the display.
• Wait for a few seconds and the display
will show "-0.0-". Now the meter is
zeroed and ready for measurement.
A
B
1.5 cm
1.5 cm
ON
OFF
ZERO
• Remove the buffered blank and
insert the second cuvet into the
instrument, making sure that
the notch on the cap is posi-
tioned securely into the groove.
• Press READ DIRECT. “SIP” will appear during measurement.
• The instrument directly displays concentration in mg/L
(ppm) of calcium hardness, as CaCO
3
, on the Liquid
Crystal Display. To convert the result to mg/L Ca,
multiply the reading by 0.4.
Note:
the test will detect any calcium or magnesium
contamination in the mixing cylinders, measuring drop-
pers or sample cells. To test cleanliness, repeat the test
multiple times until you obtain consistent results.
SAMPLE DILUTION
This meter is designed to determine low levels of hardness,
typically found in water purification systems.
When testing some other sources of water, it is not uncom-
mon to come across levels of hardness that are greater than
the range of this meter.
This problem can be overcome through dilution. Dilutions
must be performed with hardness-free water or the readings
will be erroneous.
A dilution to reduce the level of hardness by a factor of one
hundred is performed as follows:
• Fill a 1 mL syringe with the sample.
• Place the syringe in a 50 mL beaker, making sure that
the beaker is clean and empty, and inject 0.5 mL into
the beaker.
• Fill the beaker up to the 50 mL mark with hardness-free
water.
Now, follow normal measurement procedure. The true value
of the sample is the reading obtained multiplied by a factor
of one hundred (the dilution factor).
For your reference, factors to convert readings in mg/L to
French degrees (FD), German degrees (DD) and English
degrees (ED) of hardness are as follows:
1 mg/L = 0.1 FD = 0.056 DD = 0.07 ED.
READ
TIMED
The instruction listed below should be carefully followed
during testing to ensure best accuracy.
• Do not touch the cuvet walls with hands.
• In order to maintain the same conditions during the
zeroing and the measuring phases, it is necessary to
close the cuvet to prevent any contamination.
• Do not let the test sample stand too long after reagent
is added or accuracy will be lost.
• Whenever the cuvet is placed into the measurement cell,
it must be completely free of fingerprints, oil or dirt.
Wipe it thoroughly with
HI 731318
or a lint-free cloth
prior to insertion.
• It is important that the sample does not contain any
debris. This would corrupt the readings.
• It is possible to take multiple readings in a row, but it
is recommended that a zero reading be taken for each
sample and that the same cuvet is used for zeroing and
measurement.
• It is important to discard the sample immediately after
the reading is taken because the glass might become
permanently stained.
• Shaking the cuvet can generate bubbles in the sample,
causing higher readings. To obtain accurate measure-
ments, remove such bubbles by swirling or by gently
tapping the vial.
• All the reaction times reported in this manual are
referred to 20°C (68°F). As a general rule of thumb,
they should be doubled at 10°C (50°F) and halved at
30°C (86°F).
TIPS FOR AN ACCURATE
TIPS FOR AN ACCURATE
TIPS FOR AN ACCURATE
TIPS FOR AN ACCURATE
TIPS FOR AN ACCURATE
MEASUREMENT
MEASUREMENT
MEASUREMENT
MEASUREMENT
MEASUREMENT
INTERFERENCES
Interference may be caused by excessive amounts of heavy
metals.
BATTERY REPLACEMENT
BATTERY REPLACEMENT
BATTERY REPLACEMENT
BATTERY REPLACEMENT
BATTERY REPLACEMENT
Battery replacement must only take place in a non-hazard-
ous area using a 9V alkaline battery.
Simply slide off the battery cover on the back of the meter.
Detach the battery from the terminals and attach a fresh
9V battery while paying attention to the correct polarity.
Replace the battery and the cover.
Recommendations for Users
Before using these products, make sure that they are entirely suitable for the environ-
ment in which they are used.
Operation of these instruments in residential area could cause unacceptable interferences
to radio and TV equipments, requiring the operator to take all necessary steps to correct
interferences.
Any variation introduced by the user to the supplied equipment may degrade the
instruments' EMC performance.
To avoid damages or burns, do not perform any measurement in microwave ovens.
ACCESSORIES
ACCESSORIES
ACCESSORIES
ACCESSORIES
ACCESSORIES
REAGENT SETS
HI 93720-01
Reagents for 100 tests
HI 93720-03
Reagents for 300 tests
OTHER ACCESSORIES
HI 710009
Blue rubber boot
HI 710010
Orange rubber boot
HI 721310
9V battery (10 pcs)
HI 731318
Tissue for wiping cuvets (4 pcs)
HI 731321
Glass cuvets (4 pcs)
HI 731325
Caps for cuvets (4 pcs)
HI 93703-50
Cuvets cleaning solution (230 mL).
CE DECLARATION
CE DECLARATION
CE DECLARATION
CE DECLARATION
CE DECLARATION
OF CONFORMITY
OF CONFORMITY
OF CONFORMITY
OF CONFORMITY
OF CONFORMITY
IST93720R1
06/98
PRINTED IN PORTUGAL