water hardness measurement

  • Thread starter Juan De los Santos
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Thread Starter

Juan De los Santos

I need to measure the hardness of water to be used in a printing machine.
Does anybody know an equipment that can do the measurement on line?


Juan De los Santos

Arnold Dillon

You can measure conductivity on line to get a relative indication of
hardness. This measurement is somewhat temperature sensitive so the water
temp. should be within something like a 20 deg. F range.

Arnold Dillon
I.C. Thomasson Associates
Hi All

While it is probably true that you can get a relative indication of hardness
by measuring conductivity, if there is any change in the water chemistry the
relationship gets blown out to the sky. Total hardness is a measure of the
amount of Calcium and Magnesium ions in the water. Sometimes calcium
hardness is reported separately from magnesium hardness and their sum as
CaCO3 is reported as Total hardness.
Conductivity is affected by all the ions (e.g. sodium, potassium, chloride,
sulphate etc.) in solution in the water and different ions affect the
conductivity differently. The higher the concentration of dissolved salts
the higher the conductivity. An ultra pure water has a low conductivity or
if you like a very high resistance.

Unless you have a water with a fixed water chemistry I would be reluctant to
use conductivity as a method of measurement of hardness.

I get the impression that the measurement of hardness is not required on a
continuous basis, but needs to be checked to make sure no deposition occurs
in the printing equipment. In your position I would take a sample to a
chemical lab for analysis using titration.

I believe HACH make an inexpensive Colorimeter which measures hardness.This
way you could measure hardness on a daily basis.

Hope the above is of some assistance

Arthur Tua
Tua Engineering Ltd. MALTA
T (+356) 313817, 949 1286
F (+356) 319058
e-mail: [email protected]
web site: www.tuaeng.com