I am not sure what this is

[pittsfield]

Hi,

I am not sure what these blackish lines showing up on the tiles in my pool and how to treat/prevent them.

They only seem to be showing up along the grout spacing between the tiles.

Is this black algae?

My PH, Acl, and chlorine levels are pretty balanced so I am not sure what is making them appear. This is an indoor pool. I do use a solar cover at all times unless i am using it.

Thanks for your help!

 

[aeh0603]

In the pictures the lines look more of a blue/teal color than black. Does it come off when you scrub it?

Can you scrape any off with your fingernail and smear it on a white towel/napkin? If you can and it smears green it's likely algae.

Due to the blue/teal color though, I'm wondering if it could be copper staining? Do you use any products in your pool that contain copper like algaecides, chlorox products with the words blue or Blu in the name, etc?

 

[pittsfield]

Hi!

I cannot smear it off with a towel or napkin. It injected itself into the grout and I cannot seem to scrape it off.
As a matter of fact I do use Clorox 6-1 XtraBlue Shock. They do appear to have blueish tint to them. It seems to work good for my pool...do you think thats the cause of the problem and I should stop using it?

Is this not Algae then? And if not, how would you recommend me getting rid of these without removing water?

Thank you so much for your help.

In the pictures the lines look more of a blue/teal color than black. Does it come off when you scrub it?

Can you scrape any off with your fingernail and smear it on a white towel/napkin? If you can and it smears green it's likely algae.

Due to the blue/teal color though, I'm wondering if it could be copper staining? Do you use any products in your pool that contain copper like algaecides, chlorox products with the words blue or Blu in the name, etc?

 

[aeh0603]

Yes, based on your description I suspect it's copper staining. Do you have any dry acid? If so, try putting some dry acid in a sock and rubbing it on the stain (it should lift a copper stain).

I also recommend you discontinue the use of copper containing products.

I don't have direct experience with removing copper stains, so hopefully someone else will be by with advice on that (@kimkats can you help tag someone who knows more about copper stains?). In the mean time you can probably find out more by searching the forum.

 

[kimkats]

I will put in a call to @Swampwoman and see if she is around. She knows all about this mess.