Metal Stains? New Gunite Pool

bbdude

Gold Supporter
Jul 20, 2017
294
Buffalo, NY
Pool Size
28000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
Hi All - Pool is just a couple years old but we have some discoloration/black stains showing up. Predominately around transitions (eg wall to bottom).

Are these metal stains? My kit can’t test for metals but in May Leslie’s pool store showed no metals.

Any ideas? Thanks in advance for the help!

IMG_6204.jpeg
 
Hi All - I had time to use Jack’s Magic and a chlorine puck to see if they’d remove the stains.

Unfortunately, there was no noticeable improvement. Since the stains are in water 6 feet deep or more, it was hard to apply the test, but I believe I did it correctly. I’m unsure if the stains were supposed to disappear or just lighten?

I had the water tested—no significant iron or copper, and all my chemical levels are good. The stain isn’t raised or rough to the touch either.

Any other ideas? The stains are mostly at the base of the deep end walls and where the pool transitions to the deep end. Otherwise, no other staining.
 
Just wondering ... is there a chance iron stains can be present even though iron isn't showing on a water test?
Yes.

Iron will only show on water tests if it is in solution.

Iron that has deposited on pool surfaces will not show in water tests.
 
Yes.

Iron will only show on water tests if it is in solution.

Iron that has deposited on pool surfaces will not show in water tests.

Thanks! Since I didn’t get clear results with Jack’s Magic … just bought some Vitamin C so hoping to confirm my suspicions this week.
 
Vitamin C worked! It’s iron!

Closing this Friday so will focus on fixing it this spring. Sounds like AA is easier to do in spring anyway since water will be cold. Only thing that’s not clear is the filter piece of AA. It says I should remove the filters from the large egg thing?

Still not sure where the iron came from because water test didn’t show iron. I’ll have to test my fill water for iron just to eliminate it as a source, but I’m on municipal water so I doubt it.
 
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