Concrete - White Patches

[cj32991]

I had exposed aggregate concrete poured around my swimming pool. After a swim in the magnesium pool and my son jumping in the water, some water ended up on the concrete more than around 36 hours after it was poured.

As pictured. The aggregate concrete appears stained. The concrete is yet to be cut and acid washed. Should I be concerned and what is the cause of this staining? I tried to hose it off to no avail.

Thanks

 

[1poolman1]

What is the pH and alkalinity of the water in the pool? Looks to be a fiberglass or glass-lined shell. The pH in those can drop (become acidic) quickly depending on the type of chlorine used and the alkalinity has to be watched more carefully than in a plaster pool. The water may be aggressive and actually "acid washed" those portions of the deck.