What is This White Stuff?

[Bcorig]

I began my own Taylor pool analysis in September of this year. The latest numbers are pH 8, Talk 90, FCl 7 TCL 7 CYA 70 Salt 3000, Ca Hardness 440.
For the past three weeks I have noticed the accumulation of a White deposit on the brick snub. According to PoolMath it's balanced .
I have noticed that, since using the Taylor kit my Acid Demand has decreased by about 50% from when I was using Leslies' analyzer.
Any ideas?

 

[Texas Splash]

Interesting that the red brick coping is fairly thick, but also appears to be porous. Perhaps it's efflorescence that is being pulled upward through the brick and you are seeing the residual effects. Quite a bit of it in the grout as well. Have you tried to collect some of that white residue to place in a pile and pour a small amount of muriatic acid (or vinegar) on it to see if it fizzles?

Also see:

Efflorescence - Further Reading

www.troublefreepool.com

 

[JoyfulNoise]

If those bricks were not sealed and/or an appropriate waterproofing membrane wasn’t applied between them and the shotcrete wall, then that efflorescence will continue for a long time. Brick work needs to be sealed against moisture penetration as bricks are porous. Any water that gets on their surface will absorb minerals from within the brick and then deposit those minerals onto the surface as soon as the moisture dries.

TL;DR - It’s efflorescence.