About 2 weeks ago, our CYA was at 30. I added 1.8Kg of stabilizer (from Walmart) and according to the calculator it should have brought it up by 27.
Tested today and CYA is at 40. I had a similar problem last year where I would add stabilizer as per the calc but it never got to what I would think it would. No backwash done.
Why would this be?
Aside from losing stab when a pool is drained, how else would one lose it?