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Note: The 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.
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).
The conversion 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 = 0.0556 DD = 0.07 ED.
INTERFERENCES
Interference may be caused by excessive amounts of heavy metals.
Hardness Ca
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