Just starting anybody might know what these stains are?

[JanHan]

I posted my first readings the other day and am in the process of trying to get my levels right. But I was wondering if anybody might have suggestions on what these black stains are? My water hardness is out of control and know some is scaling but is the black stain mold? It is only above the waterline where water flows into pool from rocks. No mold in pool. Not sure if I should wait to even address it until I get my CYA and chlorine under control. Thanks


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[PAGirl]

Have you tried spraying it with diluted bleach and letting it sit abit?

 

[pooldv]

I have never seen anything like that. No idea what it is. I agree, try bleach and a brush first. Then try some diluted muriatic acid, start with a 3 or 4 to 1 dilution. Go stronger from there if it doesn't work. Always add acid to water when diluting.

 

[JanHan]

Thanks! I'll try some bleach first and go from there


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