Black stains on all White PLASTIC/PVC surfaces

[mystar60]

I am getting a black stain on the 3 discharge jets, 2 wide mouth skimmers, and now the 2 screened returns in the deep end.

My readings for the pool are:

Fc - 9
pH - 7.8
TA - 70
CH - ~100
CYA - 65
Salt - 3200

I noticed this last season and it was very mild compared to this season.
I don't know what could be causing this or how to address this issue.
A friend advised I have the SWG cell cleaned but I doubt that would do it.

Any advice would be appreciated .

Thank you

Kevin

 

[Richard320]

Welcome!

Have you ever used any algaecides or mineral systems in your pool? Metals are the most likely cause. Find some Vitamin C tablets and set one on the black spot for about fifteen minutes and see if it leaves a white spot.

 

[mystar60]

Ok I will do that and let you know.

Thank you

 

[mystar60]

I placed the Vitamin C tablet on the skimmer and it did leave a white spot.
I usually had the pool opened by the company that installed it 2 years ago. Every opening I believe they did put a Algaecide and a water Clarifier in. I know this because they always left me the empty containers. This is the first year I opened it myself and did not use ANY chemicals upon opening. I turned on the pump for 3 days strait and turned the SWG to Super Chlorinate.
Did I over look something?

 

[Loudonno]

Some algaecides contain copper, maybe thats the problem.

 

[mystar60]

It could be.

So far the Vitamin C helped clean the stains when I rubbed it on the stained surfaces. The stains have not returned yet, maybe too soon to notice.
I just need to determine the correct approach to this issue"$$$"

I have just read this article - pool-school/metal%20stains

Which leads to this Solution: ascorbic-treatment-to-rid-pool-of-metal-stains-t2298.html