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.
Soluable
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 aeriate the water
to release the excess oxygen.
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