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Stains On The Pool Surface

Items Needed To Test Pool Surface Stains:

  • Chlorine Puck (vinyl pool only)
  • Sock (vinyl pool only)
  • Liquid Muriatic Acid (Hydrochloric Acid) or Acid Magic (Muriatic Acid Replacement)
  • Non-Chlorine Shock (Potassium Monopersulfate)
  • PVC Tube (long enough to easily reach from the surface of the pool water to the location of the stains on the pool surface under the water)
  • Borax (May Be Needed)
  • Baking Soda (May Be Needed)
(Phosphates have to be eliminated for stain removal efforts to work.  Use a phosphate remover to get the phosphates as low as possible as part of the effort to remove stains.)

If there are any stains, discolorations, or markings anywhere on the pool surface, the stains need to be tested to determine how to remove them.  (If the pool is NOT vinyl you can skip the chlorine test).  The most likely product to affect the stain will be the non-chlorine shock, so starting there is a safe bet.

Follow these steps to find out what removes the stains:

Chlorine Test

1)  Put a chlorine puck inside of a sock and place the puck in direct contact with the stain.  

2)  See what happens.  Also, notice what happens when the chlorine is removed.  If the stain went away, did it return after the chlorine was removed?

Results:  If the stains went away with the chlorine, and maybe even returned when the chlorine was removed, the problem is organic.  If this is the case you should contact us  to get instructions on how to get rid of it.

Liquid Acid Test

1)  Submerge a piece of pvc pipe so that the other end is close to an area of staining.  

2)  Pour liquid acid down the pipe so the acid is applied directly to an area of stain.  

3)  Notice whether the stain reacts, and how it reacts.

Results:  If the stain reacted to the liquid acid, by going away,  The stain is a metal.  

To Remove Stain:

1)  Lower the copper level to .3 ppm or less.

2)  Add liquid acid to the pool (in a bucket mix water and acid, putting water in the bucket first, then the acid - quantities aren't important but you want more water than acid).  A total of 2-3 gallons will be used.

3)  Walk the acid/water solution around the pool, adding it to the pool water until the stain is gone.

5)  If the stain completely disappears with the acid then use Borax at 4lbs per day to raise the pH back to 6.6 - 7.0.  

6)  If there is still some staining after 3 days of having a lower pH, then use baking soda to raise the pH back to 6.6.  it is important to not let the pH rise above 7.2 or the stains will reoccur.

Non-Chlorine Shock Test

1)  Thoroughly rinse the pvc tube between any tests to make sure the products don't mix.

2)  Submerge the pvc pips so it is close to an area of staining.  

3)  Pour non-chlorine shock down the tube to apply it directly to the stain.

4)  Notice whether the stain reacts, and how it reacts.

Results:If the stain is removed with the non-chlorine shock, the stain is a metal.  

To Remove Stain:

1)  Using 5 lbs per 20,000 gallons of pool water non-chlorine shock (potassium monopersulfate), apply daily until stain is gone.

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