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Metals & staining...

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 “Verdigris” 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.

Prevent metal stains by using
BioGuard Pool Magnet or Jack's Magic Products (a sequestering agent) when filling the pool then adding a maintenance dosage monthly. Once you have treated metals stains or colored water, you must continually do this to prevent a recurrence. These 2 types of products only keep the dissolved metals from reacting with chlorine or other oxidizers, they DO NOT remove them. Metals cannot be chemically removed, they must be physically removed.


To REMOVE metals, use either BioGuard Sparkle-Up or CuLator. CuLator is an excellent product that easily traps & physically removes heavy metals such as Iron, Copper, Manganese, Silver, Cobalt, Nickel and Lead. Simply place the CuLator pouch in your skimmer or pump basket - depending on the product - and allow the CuLator to work.

If you have well-water, treat automatically immediately.

If you have municipal water, Pool Magnet won’t hurt.

If it’s too late & you already have staining:


1.   Get the water balanced.  Keep in mind that further discoloration COULD occur.  This is a temporary phenomena & will clear once the treat process is complete.

2.   For light staining of iron & copper, use BioGuard Pool Magnet at a rate of 1 qt. per 10,000 gallons of water.  BioGuard Pool Magnet works well on “fresh” stains.  Avoid shocking the pool for about 3 days.

3.   For heavy staining, Jack’s Magic Blue Stuff is an excellent product.  We like Jack’s Magic because you can have high or higher amounts of chlorine present (in excess of 10.0 ppm).  Click here for more information treating with Jack’s Magic products.

4.   Heavy metal staining on vinyl, fiberglass or acrylic steps can be treated with Jack’s Magic Step Stuff. 

5.   Save yourself time, money & effort using Jack’s Magic Stain ID Kit.  It really helps in identifying the exact metal that’s causing the stain.

Download & Print a FREE brochure about Metal Stains & Staining

Some of the information contained in this article is courtesy of the BioGuard® Chem PLUS 2003, 2004, H2Know 2016 Reference Guide.

If you still need help, here's how to reach us:

Telephone (during store hours): Shelton, CT  203-377-0100
Email: techhelp@parpool-spa.com

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Pool Stains & staining caused by metals.  Colored water.

MOST, but not all, staining on pool surfaces is 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.  These metals are already dissolved in the water.  Whether you use 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.