Any idea what's going on here?

[ak29]

Pool filled with water on 1-17.

Pool maintained the TFP way from 2-7.

The deck was demolished end of April and then repoured at the end of May.

White stuff appears in some places but not in others.

Latest Test Result Summary:
FC: 11.0 (16 hours ago)
CC: 0.0 (16 hours ago)
pH: 7.7 (16 hours ago)
TA: 60 (4 days ago)
CH: 425 (16 days ago)
CYA: 80 (7 days ago)
SALT: 3600 (4 days ago)
TEMPERATURE: 92° (16 hours ago)
CSI: -0.18 (16 hours ago)

 

[wireform]

To me it seems water is seeping from behind somehow in that spot perhaps from the deck/coping and not related to the pool chemistry.

 

[Turbo1Ton]

Looks like efflorescence.

Efflorescence - Further Reading

www.troublefreepool.com

--Jeff

 

[ak29]

Looks like efflorescence.

Efflorescence - Further Reading

www.troublefreepool.com

--Jeff

Hmm, Efflorescence. Maybe. While it has been a long time since it has rained here, the sprinklers could make up for that by enveloping the pool in water. Thank you for the links; they were exciting and educational. If one assumes pools := bridges and buildings, I should see skyrocketing ph, but I'm not - new plaster + SwG explains a gallon of acid a month.
So far it is localized to small areas - it'll be interesting to see if it spreads.

 

[ak29]

To me it seems water is seeping from behind somehow in that spot perhaps from the deck/coping and not related to the pool chemistry.

That was my initial thought because it's only appearing in certain places. The demolition crew was very skilled but it was a demo job - stuff gets broken. And some tiles were broken and replaced, and cracks in the grout were fixed.