Pool Stains & staining caused by metals.
MOST, not all, staining on pool surfaces are preventable.
The problem is most people don’t realize they
have metals in their water. Even trace amounts of these
metals (iron, copper, manganese, cobalt, silver) can
cause staining. In fact there’s enough copper
in ONE penny to completely stain an average sized swimming
pool! Obviously, the conditions have to be right. This
is where prevention & good, proper pool care come
into play.
Here’s what happens: metals come into your pool
whenever fresh, make-up water is added. They’re
dissolved in the water. Whether it’s municipal
water or well water, metals can be present. As the metals
accumulate, the greater the chance that they will eventually
come out of solution. Once out of solution, they make
the water cloudy or worse, they “plate out”
on the pool’s surfaces & stain. Metals can
come out of solution through a variety of ways. But
there’s 2 that typically happen.
When a pool is shocked whether with chlorine or a non-chlorine
oxidizer, the shock oxidizes everything in the water,
including metals. Oxidized metals become “rust”
in the case of iron or “Verdi gris” in the
case of copper.
In the second way, metals come out of solution or are
left “exposed” when the pH, Total Alkalinity
and/or Calcium Hardness are left unchecked & allowed
to go low (pH below 7.2, Total Alkalinity below 80 ppm
[non-Pristine Blue pools], Calcium Hardness below 100
ppm). The water becomes aggressive & the metals
are more susceptible to oxidation. In many cases, pool-owners
don’t properly test their water & more likely
rely on the “look” of the water (the water’s
clear, everything must be alright). This is typically
the case with blonde hair turning green – low
pH helps bring copper out of solution & “plates”
it out on the person’s hair! Then people blame
the chlorine! It’s the copper in the water.
When it comes to testing, remember that you can only
test for metals when they are in solution. Once oxidized,
the metals come out of solution & cannot be tested.
That’s why once a metal stain has occurred, the
metal test will NOT show any metals present.
Here’s how to prevent metal stains:
Keep the water balanced. pH 7.4 – 7.6; Total
Alkalinity 125 – 150 ppm (vinyl pools), 80 –
125 ppm (plaster / gunite pools) (Please note that these
TA values ARE NOT applicable in Pristine Blue treated
pools where the TA is to be maintained at no higher
than 80 ppm); Calcium Hardness 200 – 250 ppm (vinyl
pools), 225 – 275 ppm (plaster / gunite pools).
In other words, have your water professionally tested
at opening, mid-season & at closing (at least) –
make sure they do a copper & iron test.
If you still need help, here's how to reach
us:
Telephone: 02 9729 3964
Email: thatpoolguy@bigpond.com
Alternatively you can complete our
online
form or
brochure
request.
