Help! MagicJack’s O2 safe shock creates brown stain

[QPSUtah]

I was using the stain identification kit to identify some discoloration in a pool. It’s a turquoise green, most likely copper, but wanted to use the test to confirm. First time using the test.
Pool parameters were very close to recommended levels.

Upon putting in the shock, it immediately created a brown stained area that isn’t brushing away.

See pic. Any suggestions?

 

[JoyfulNoise]

Probably iron or copper precipitation. Hit it with vitamin C - if it disappears its iron, if it gets darker and brown/black then its copper.

 

[JamesW]

Looks like copper and silver.

Does the customer have an ionizer or a metals treatment cartridge?

 

[QPSUtah]

Looks like copper and silver.

Does the customer have an ionizer or a metals treatment cartridge?

No. They just bought the house. I found an empty container of Clorox Xtra Blue on the side of the house. I’m guessing that is where the copper came from.

 

[QPSUtah]

Probably iron or copper precipitation. Hit it with vitamin C - if it disappears its iron, if it gets darker and brown/black then its copper.

Good idea. I’ll try vitamin C. Two of the other test spots turned dark gray from the iron test mix. However, sprinkling some granular chlorine seemed to take get rid of the dark gray staining in short order.

Sprinkling some granular on the brown oxidizing spots also lessened it, but didn’t fully eliminate it.

I mentioned below, pretty sure it’s copper due to the color and also found empty container of Clorox xtra blue which contains copper as an algaecide I believe.

 

[JoyfulNoise]

Vitamin C gives the clearest difference between iron and copper. Iron redissolves leaving no trace and copper oxidizes further getting darker brown. Granular shocks can be acidic which can lift both types of staining thus leading to little difference between the two. This is why TFP suggests using a small poultice of crushed vitamin C tablets to help with stain ID. No need to buy expensive ascorbic acid powder if you’re just going to check a spot.

 

[JamesW]

Silver stains can turn a purplish color before clearing.

Silver stains are usually brown like in the picture below.

Iron is also brown, but it is a different brown from silver.

Iron tends to have an orange component.

Turquoise is is usually copper.