White Stuff pile in hot tub?

[SkiBikeGolf]

I drained half my pool and added 8,000 gallons to refill. I cleaned my Filter, added DE, and have gotten my chemistry close to where TFP recommends:

FC: 9.5
pH: 7.5
TA: 150
CH: 450
CYA: 90
CSI: 0.30

Just yesterday, I noticed an accumulation of "white stuff" in my hot tub. It is no DE. Any idea what it might be?

 

[YippeeSkippy]

Can you pick it up? If so let it dry on a paper plate, then add a drop of acid on it. If it bubbles and fizzes its calcium. If you can't pick it up and it blows away I'd think dead algae.

Maddie

 

[SkiBikeGolf]

Maddie,

Thanks for the suggestion: I gathered some of the white stuff, let it dry and placed on a paper plate.

I added 3 separate drops of muratic acid to the white stuff and saw NO bubbling or fizzling.

chemgeek, do you have any suggestions for identifying the white stuff.

Show below is my test as suggested by Maddie

 

[mknauss]

Looks alot like stabilizer granules.

 

[SkiBikeGolf]

Hmmm, if they are stabilizer granules, I wonder if I could add them to tap water and then test for the presence of CYA?