Soda Blasting Tile

[SmittyGESB]

Ok, Folks, I'm new to the forum. I have been a pool owner for in upwards of 10 years. i started a soda blasting business 2 years ago. I added tile cleaning to my business last year. i have a pool that I blasted with baking soda and the pH wasn't balanced for 2 weeks. now there is a white substance that looks and behaves like D.E. on the bottom of the pool. The home owners think that it is my soda. The pool pH is a little basic at 7.8 total alkalinity is 90 the CYA is 80 and the Calcium hardness is low at 70. the pool is around 25,000 gallons. So whats happened is there pool guy came out and cleaned the filter and stated that there was a hard substance caked on the filter. when I observed this substance after it had dried it looked similar to a paint chip but was easily crushed into a fine powder. The bottom of the pool is still covered with this sediment, you can easily brush it off but the water just turns cloudy and then the white sediment settles right back on the bottom. Anyone with information please help.
Thank you JonMark

 

[JohnT]

Soda is added to pools all the time for chemistry adjustments. It is water soluble.

But what were you cleaning off the tile if their CH is so low? If this is a plaster pool with tile, they need to maintain a reasonable CH level to protect their plaster.

 

[SmittyGESB]

I was blasting Ca build up off of the tile.

 

[JohnT]

I was blasting Ca build up off of the tile.

I'd think it far more likely that it is the calcium. See if it dissolves in muriatic acid.

They are going to damage their pool with CH at only 70ppm.

 

[SmittyGESB]

Ok, I will see if it dissolves in muratic acid! I have been going out to the residence once a day,brushing and testing the water! I added one treatment of Ca to the pool (25lbs) in attempts to raise the Ca hardness. I added acid to the pool to to bring the pH which was at 8 ,down to 7.4 ish.
What would have caused this chalky appearance to appear 2wks after I blasted the tile?
Thanks
JonMark