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I have Red Stains in my Sinks and Other Fixtures -- Help!
Red stains are normally caused by iron
in the water. You must test to determine the amount and the type of iron
you have. Some types are: oxidized, soluble, colloidal, bacteria or organic-bound.
All are a problem! It only takes 0.3 ppm to stain clothes, fixtures, etc.
Oxidized
This type of iron is usually found in a
surface water supply. This is water that contains red particles when first
drawn from the tap. The easiest way to remove this type of iron is by
a fine mechanical filter. A cartridge type filter is usually not a good
solution, due to the rapid plugging of the element. Another method or
removal is by feeding a chemical into the water to cause the little particles
of iron to clump together, and then fall to the bottom of a holding tank,
where they can be flushed away.
Soluble
Soluble iron is called "clear water" iron.
After being drawn form the well and contacting the air, the iron oxidizes,
or "rusts", forming reddish brown particles in the water. Depending on
the amount of iron in the water, you may solve this problem with a water
conditioner, or a combination of softener and filter. You may use an iron
filter that recharges with chlorine or potassium permanganate, or feed
chemicals to oxidize the iron and then filter it with a mechanical filter.
You can sometimes hide the effects of soluble iron by adding chemicals
that, in effect, coat the iron in the water and prevent it from reaching
oxygen and oxidizing.
Colloidal
Colloidal iron is very small particles
of oxidized iron suspended in the water. They are usually bound together
with other substances. They resist agglomeration, ie, the combining together
of like substances forming larger, heavier, more filterable ones, due
to the static electrical charge they carry. This iron looks more like
a color than particles when held up in a clear glass, as they are so small.
Treatment is usually one of two: Feed chlorine to oxidize the organic
away from the iron, thus allowing agglomeration to occur, or, feeding
polymers that attract the static charge on the particles, forming larger
clumps of matter that is filterable.
Bacterial
Iron bacteria are living organisms that
feed on the iron found in the water, pipes, fittings, etc. They build
slime all along the water flow path. Occasionally, the slimy growths break
free, causing extremely discolored water. If a large slug breaks loose,
it can pass through to the point of use, plugging fixtures. These types
of bacteria are becoming more common throughout the United States. If
you suspect bacteria iron, look for a reddish or green slime buildup in
your toilet flush tank. To confirm your suspicions, gather a sample of
this slime and take it to your local health department, or water department
for observation under the microscope. This type of iron problem is very
hard to eliminate. You must kill the bacteria, usually by chlorination.
You must use high amounts of chlorine throughout your plumbing system
to kill all organisms. You may find it necessary to feed chlorine continuously
to prevent regrowth. A filter alone will not solve this problem.
Organic bound
When iron combines with tannins and other
organics, complexes are formed that cannot be removed by ion exchange
or oxidizing filters. This iron may be mistaken for colloidal iron. Test
for tannins; if they are present, it is most likely combined with the
iron. Low level amounts of this pest can be removed by use of a carbon
filter, which absorbs the complex. You must replace the carbon bed when
it becomes saturated. Higher amounts require feeding chlorine to oxidize
the organics to break apart from the iron and cause both to precipitate
into a filterable particle.
I Have Blue or Green Stains on
my Fixtures -- Help!
You either have copper in your water supply,
or you have copper pipes and corrosive water. Test for copper in your
water. Test the pH, total dissolved solids content and the oxygen content
of your water.
Copper
Copper can be removed by ion exchange,
ie, a water softener. The removal rate is about the same as it is for
iron.
Copper pipes and corrosive
water
If your pH is from 5 to 7, you may raise
it by passing the water through a sacrificial media. By sacrificing calcium
carbonate into the water, the corrosively will be reduced. If the pH is
below 5, you will need to feed chemicals into the water.
If the corrosively is caused by excess oxygen, the hot water will be much
more corrosive than the cold. Treatment is by feeding polyphosphate or
silicates to coat and protect the plumbing, or to aerate the water to
release the excess oxygen.
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