Should I be worried?

[Oli77]

We lowered the water level during closing and I noticed the white deposit below.
It does not come of when brushing.
Is this under the water level too?
Should I be worried?
Calcium?

 

[ajw22]

Try posting your pics again.

Pour some muriatic acid on the white deposit and see if it fizzes and comes off which would show it is calcium.

Otherwise it can be the gelcoat fading.

Fiberglass Discoloration (Faded & Chalky) - My Story

The fiberglass construction and gelcoat is the same. True, wax will not last as long in a pool environment compared to a dry side of hull but it still helps protect. Restoration is the same as the chaulking comes from The same UV oxidation that damages boat fiberglass.

www.troublefreepool.com

Fiberglass Pool Owners - Survey (Results)

Fellow TFP fiberglass pool owner, TFP is always gathering data in an to increase its extensive knowledge base and analyze that information to provide members with the most accurate and reliable information possible. As such, we developed the following survey in an effort to capture...

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[Oli77]

Not sure what is going on the pic. Are you not seeing it?

I put a few drops of muriatic acid on it and it did not fizz. I applied it for a few seconds and then wash it off. Waiting for it to dry to see if it clears an area.

 

[Oli77]

 

[ajw22]

Not sure what is going on the pic. Are you not seeing it?

This is what I see...

 

[Rocket J Squirrel]

I see a perfectly fine photo.

 

[Oli77]

Do you see a pic above in post #4 now?

So the muriatic acid did not clear that spot now that it is dry.
If I scratch it with my fingernail, it goes away. And It is shinny underneath.

 

[ajw22]

Sounds like a scum line.

Try using a Magic Eraser on it.

Magic Eraser on Pools - Further Reading

www.troublefreepool.com

 

[Oli77]

The scum line is actually above (can't see it in pic, it is very faint) the white line about one inch. Not sure that is it. Going out there with a magic eraser....

 

[Oli77]

Magic eraser pretty hard on the spot gets it cleared up some, and that spot turns a bit more blue.
Same as the spot I cleared with my fingernail.

 

[Oli77]

Blue circle is the fingernail scratch test and the yellow is magic eraser rub.

 

[Oli77]

Not worried then.