Treating black algae

The white cloud might be paint, but the scratch test seems to indicate that it is not paint.

I would say that it is undetermined at this point.

In any case, a full SLAM is probably required.

The surface is in poor condition in any case, so it will be a challenge to maintain.
 
To me, it looks like paint, but I can't tell for sure without actually being there.

Maybe get a local professional expert to check for you to advise you about the surface.

Check the permits issued to your property address to see when the pool was built.

Ask the old owners when the pool was built and what work has been done to the pool including if the pool was painted or replastered or maybe refinished in fiberglass.
 
Ok, I have set up someone to come look at it. Can you advise me on the full SLAM? We shocked the pool up to 20 Monday night and we have been adding chlorine to maintain it at 15-20 since then. Should I jump it back up to 20? This morning test showed 13.5, I have not added any more chlorine yet.
 
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I did.
IF this is black algae, no need to follow SLAM. So IF you pass an OCLT, then just follow the Black Algae document I linked to early in the thread.
 
Here is what the article says.

The article says that you can maintain "Up to" SLAM levels.

Different people will have different opinions about how aggressive you want to be in treating the black algae.

You can choose how aggressive you want to be in treating your case depending on what you feel best about.

Black algae can be embedded into the plaster very deeply and it can be difficult to deal with especially if the plaster is in poor condition where the black algae can get deeper into the plaster.

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It partly depends on how bad the black algae is, your patience and how the black algae responds to the treatment.

If you use elevated but non-SLAM levels and the black algae is noticeably removed in a day or so, then that is fine.

However, if the black algae is not responding quickly enough for you, you can go up to SLAM levels to try to get a better and faster response.

Aggressive brushing helps.

In any case, black algae is actually a toxic black bacteria like toxic black mold that is nasty and very difficult to eradicate.
 

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Run the pump continuously per SLAM protocol?
I would.

Also, break down the filter and give it a good cleaning so that it is working at peak efficiency.
Also do I consider the grey to be staining or still signs of algae?
I can't tell exactly what you have from the pictures.

It might be a combination of black algae and maybe some type of stains from metals or other things.

It is difficult to tell from looking at pictures and not being able to see it in person.

Let's see what your local professional says.

When are they scheduled for?
 
To me, the darker areas look like places with missing paint.

You might have white paint over a darker plaster.

So, any missing paint will expose the plaster and it will look different.

Can you feel any texture difference between the white areas and the darker areas?

Any sort of missing paint or pitting will harbor black algae as it is more porous and it helps protect the algae from brushing.

Pitted areas are also more likely to become stained or retain dirt.

Until you can definitively determine if it is paint, or not, it will be difficult to give you a better diagnosis.

Follow the Black Algae protocol as outlined in the article.
 
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