LaMotte HARDNESS IN WATER 1606 - Manual (Page 5)

WATER HARDNESS: METHOD II
1.
Fill the test tube (0608) to the 10 mL line with sample water.
2. Use the pipet (0363) to add one drop of *Hardness Soap Reagent
(4768).
3. Cap and shake vigorously to form a lather. If sufficient lather does not
form, proceed to Step 4. If sufficient lather forms, proceed to Step 5.
NOTE: The lather should completely cover the surface of the solution
when the vial is laid in a horizontal position, and should last for five
(5) minutes.
4. Continue adding *Hardness Soap Solution (4768) drop by drop,
shaking and checking lather formation after each drop, until lather
forms and last 5 minutes. Count the total number of drops added.
NOTE: Be sure to include the drop added in Step 3.
5. Use the following chart to determine the sample hardness.
# OF DEGREE
DROPS OF HARDNESS RANGE
1-5 soft 20-100 ppm
6-10 hard 120-200 ppm
more than 10 very hard over 200 ppm
NOTE: Each drop of Hardness Soap Solution is equal to 20 ppm hardness.
The abbreviation “ppm” stands for parts per million; one ppm is equal to
one particle of substance in a million particles of solution.
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HARDNESS IN WATER
Hardness is one of the common factors tested in water of all types and uses,
from environmental testing to drinking water to water used in industrial
processes. Defined as the amount of calcium and magnesium found in the
water, very high or low hardness levels can ruin expensive equipment, or
make water unsuitable for aquatic life.
Calcium and magnesium are elements found in many rocks, both above
and below the ground. As water passes over these rocks, the calcium and
magnesium slowly dissolve into the water. The amount of calcium and
magnesium dissolved into the water is dependent upon the hardness of the
rock. Rocks which dissolve easily and contain large amounts of calcium or
magnesium, such as sandstone and limestone, release more calcium, and
this water is referred to as “hard.” Conversely, water which passes through
rocks containing little or no calcium or magnesium, receives less of these
elements and is considered “soft.”
The type of rock is not the only factor which determines the hardness of
the water; pH is also important. Water that is acidic, or has a low pH, will
cause more calcium and magnesium to dissolve from the rock than water
with a high pH. Water which has been treated for home or industrial use
may be returned to the natural water supply with a different hardness level
than it originally had.
Water hardness is important to everyone, both homeowners and members
of industry. As soft water contacts surfaces containing calcium or
magnesium, such as plaster pool walls, it will remove these elements from
the surface. This is referred to as etching. Conversely, hard water will leave
calcium and magnesium deposits in pipes, boilers and equipment,
potentially causing clogs. These deposits are known as scale. In the home,
hard water reduces soap’s ability to lather, and may leave a film on clean
dishes and clothes.
Water can be treated to make it harder or softer. Calcium or magnesium,
often in the form of calcium chloride can be added to a water supply to
raise the hardness level. Water which is too hard can be treated using a
water softener, which removes calcium and magnesium so the water is
softer for use.
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