White substance on pool siding

[SumoSimo]

Hi all. I'm a new pool owner, and I'm observing white substance on the side of my pool. I'm not quite sure what it is, but I'm guessing it's calcium scaling?

I have attached pictures. Many thanks.

 

[ajw22]

The white stuff is efflorescence…

What is Efflorescence & How to Remove Efflorescence? | NMP

Efflorescence is a crystalline deposit of salts. Typically found on porous materials that are exposed to moisture. Learn how to prevent and remove it.

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