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STAINING AND SCALING
All water contains some levels of minerals and metals.
When the minerals or metals are
dissolved and in suspension they are not visible. If they precipitate, or fall out of suspension,
staining or scaling can result.
Metals such as copper, iron or manganese in sufficient
quantities can all cause staining. Prior to treatment you must first determine the cause.
or bacteria can cause green, black, yellow, brown or pink discoloration.
deposits can generally be distinguished from mineral or metal staining by their response to
chemical treatments (sanitizer and algaecide) and in most cases can be removed with a
vigorous brushing (although they may grow back)
ee Algae for more information
worms and other organic material left in the pool can also cause staining.
This type of staining
will usually respond to a sanitizer and a follow up stain remover.
Ruling out the above, one can assume that the discoloration, throughout the water or in
deposits, is caused by metals or minerals that have oxidized or dissolved and have
precipitated (come out of solution).
Unbalanced pH, Alkalinity and the addition of sanitizers
are all possible causes for such precipitation.
High levels of metallic salts such as calcium or
magnesium in suspension may cause cloudy water, when they form hard white deposits or
crystals on the pool surface it is referred to as scaling.
Heavy metals like copper and iron will
cause discoloration or when deposited, staining.
Green usually indicates copper or iron, red
and brown –iron, black or brown -manganese.
As with all water problems, prevention is preferred to treatment.
The best way to prevent
staining is to have your pool water tested by your pool dealer PRIOR
to the addition of ANY
Often the original source water that you use to fill your pool may contain iron
or other metals or minerals that are not visible to the naked eye.
If a test reveals the presence
of metals or minerals in your water your pool dealer can recommend a treatment method, often
consisting of the addition of a sequestering or chelating agent.
These chemicals are used to
help bind the metals together so they will not precipitate.
Some pool water will require regular
additions of these chemicals, especially after the addition of make-up water.
Have your water
professionally tested for metal content at the beginning of every season.
Another key in
preventing precipitation is to follow the chemical guidelines for adjusting pH and alkalinity,
high, rapid fluctuations can cause precipitation.
Corrosion of metal equipment components
due to unbalanced pH and Alkalinity can also cause dissolved metals to precipitate in the
If staining or scaling does occur your pool dealer can recommend a stain and scale
remover for treatment.
Follow the steps below to help prevent staining and scaling:
Have your water professionally tested for metals- results should be 0 ppm.
ADD ANY CHEMICALS UNTIL THIS TEST IS PERFORMED*
Follow water balance guidelines for pH, Total Alkalinity, TDS and
Calcium Hardness. Add pH and Total Alkalinity adjusters following
the application directions closely.
add too much chemical
or make too rapid of an adjustment in a short period of time or
precipitation can result.
Routine maintenance doses of a sequestering or chelating
agent will help prevent staining and scaling- Strongly
recommended in plaster and fiberglass pool finishes.
Poor filtration or circulation will accelerate metal precipitation
Pool owners with plaster and fiberglass pool surfaces
need to be diligent in stain and scale prevention.
METALfree is a highly effective metal deactivation
agent that prevents staining and discoloration from
trace metals such as iron and copper. METALfree
also prevents scale build-up due to calcium and
. These trace metals and minerals
may already be in the pool water or in the fill water.
It should be used as part of a well designed weekly