60
61
Hardness Ca
Note
:
This test will detect any calcium contamination in the beaker, measuring syringes or sample cells. To
test cleanliness, repeat the test multiple times until you obtain consistent results.
Note
:
For better accuracy wash glassware with HCl 6N.
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 uncommon 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.
INTERFERENCES
Interference may be caused by excessive amounts of heavy metals.
Hardness Ca
• Add 1 drop of HI 93720C-0 EGTA solution to one cuvette (# 1), replace the cap and
invert the cuvette several times to mix. This is the blank.
• Place the blank (# 1) into the holder and close the lid.
• Press ZERO key. The meter will show “-0.0-” when the
meter is zeroed and ready for measurement.
• Remove the blank and insert the second cuvette (# 2)
into the instrument.
• Press READ to start the reading. The instrument dis-
plays concentration in mg/L of calcium hardness, as
CaCO
3
.
• Press the
or
to access the second level of functions.
• Press the
Chem Frm
functional key to convert the result in mg/L of Calcium (Ca).
# 1
# 2
# 1
• Press the
Unit
functional key to change the current measurement unit. The results can be converted to
French degrees (°f), German degrees (°dH) and English degrees (°E).
• Press the
or
to go back to the measurement screen.
