Is this Algae or metal staining, or what? (pictures attached)

[edavis6678]

After joining this great forum a week or so ago I'm beginning to find that all of the advice I've been given on my pool in the past by various folks is full of ****...So, i bring another question that maybe someone here can help answer. Can anyone tell me if the stains on the bottom of my pool are "Algae" (some kind or another), or are they "metal" staining absorbed by the poorly mixed plaster as what I was previously told. (and that a re-plaster would be the answer to fix that)

I'm in the process of currently lowering my CYA (working on a partial or full drain), so I can properly sanitize with lower FC and wanted to know if i should be looking at re-plastering, or just looking at doing a SLAM to get rid of this. (if it's algae)

Picture of Steps



Deep end side



Shallow end of pool



Full shot of pool



Thanks in advance for reading!

 

[Richard320]

That first picture looks like plaster delaminating to the right of the stains. To fix that, you're looking at a replaster.

To ID the stains, set a cheap Vitamin C tablet on one of the brown stains for ten minutes or so, then remove it. If you have a white spot where it was, it's metals.

If the stained areas feel raised and rough, it's Calcium scale thanks to hard water, high evaporation, and high pH not kept in check.

 

[edavis6678]

If the stained areas feel raised and rough, it's Calcium scale thanks to hard water, high evaporation, and high pH not kept in check.

I'm pretty sure it's raised and rough. My calcium levels are through the roof so this doesn't surprise me...if I lower the total calcium level (with a partial or full drain) will these go away or can you recommend a treatment option?

Also..why are they brown? I thought calcium would be white

 

[Richard320]

An acid wash or a no drain acid wash or a drain and sandblast will get rid of the Calcium scale. Any of those options will weaken your plaster.

Then there was this. I didn't do this, I'm just posting the link.

The brown is probably from dirt or rust or decayed-leaf-tea that was in the water when the stuff started sticking. Impurities embed within crystals easily. Even with sparkling clear water, Calcium scale is sort of a tannish-grey color, not gleaming white like movie-star teeth.