Circular brown stains on in-ground Gunite pool - photos

[reefpool]

 

[reefpool]

Hi everyone! please see above the photos with one deep in the pool and one on the stairs. My ugly feet are included as a size reference, these stains are all circular and about 1.25” diameter. They are all just a circle outline. There are more in the deep end, two are much worse. Any ideas? All chemistry is spot on (chlorine is 2.5-3.5, pH 7.7-7.9, alk 100). I’m not sure how long the stains are there now because we have stains come and go and I’m just realizing these are not able to be wiped off. Thanks so much for any help!!

 

[CrystalRiver]

Crush up a vitamin C tablet and put it on the stain. See if it lifts. If so, it's iron.

 

[reefpool]

Thanks, will grab some tablets and do that. Any idea where this might be coming from? Odd the circles. I can grab an iron test to see if I can get a read on the water. I think there is a rusting fitting at the pump. I just can’t think why these would all be circular! ??

 

[reefpool]

I did Jacks magic test kits and the sulfamic acid (#2) works immediately. The #1 didn’t do anything at all. From this info and the photos do you think this is copper staining? I know the prior owners used the chlorine tabs. I have been here a year and only use liquid chlorine, muriatic acid and baking soda to balance the pool. Should I get a copper test kit or is this level likely to be low. I’ve got a lot of water and zero interest in draining. I have a brand new Raypak heater- old one was removed before we came in.

thanks for advice!

 

[ajw22]

Do you only have those four circles?

If so, ignore it. The treatment will be worse than the disease.

Bring your pool water into a pool store and have them test it for copper. Thank them for the test and don't buy anything.

 

[YippeeSkippy]

We've seem small stains like that from those covered hair elastics and such.

 

[reefpool]

Thanks, everyone. Do you think it’s worth buying sulfamic acid crystals and diving to scrub these off? Will that do any harm? That stuff took the stain out in just a couple wipes. I definitely am not treating the water body.

btw a hair band is totally possible. Maybe it started on the front step, fell in to the bottom and then was drug around in the deep end by Polaris before being removed and never realized hahaha. There are maybe 10 of these stains, mostly at the deepest part of the pool.

 

[ajw22]

Sulfamic acid is used to lift copper stain and will mess up your FC and CC testing for a while. I would not use it unless you have a widespread problem. Read...

Acid - Further Reading

www.troublefreepool.com

 

[reefpool]

Sulfamic acid is used to lift copper stain and will mess up your FC and CC testing for a while. I would not use it unless you have a widespread problem. Read...

Acid - Further Reading

www.troublefreepool.com

Thanks. In what quantity, approximately, would this do harm? If I can just use a handful of crystals to spot clean with no impact then it’s a no brainer, but if even small quantities do harm I’ll pass on cleaning. Thanks!

 

[ajw22]

Thanks. In what quantity, approximately, would this do harm? If I can just use a handful of crystals to spot clean with no impact then it’s a no brainer, but if even small quantities do harm I’ll pass on cleaning. Thanks!

Let's see if @JoyfulNoise knows how much sulfamic acid would cause CC problems in your 50,000 gallon pool.

 

[JoyfulNoise]

Did vitamin C (ascorbic acid) not work?