Does unused CYA "expire" or "go bad" ???
I have ~ 7,000 gal Intex AGP so last year I bought bucket of CYA @ Leslie's pool store. I added to pool, levels came up, all was happy in the world of my pool.
This year, I set up pool, add water, bleach to get CL in, turn on SWG, add muriatic acid to get PH right, add CYA. Wait a week to test, fill entire tube and it's clear. Hmmm... add a bit more wait a few days test. Still clear. I tried *gasp* test strip, it show 0-20 (or whatever the low is). Hmmmm... take sample to pool store - they say it's ~ 20 ppm. OK, I'll just add a bit more - do that and test again. Still clear in CYA tube test.
So my only thought is that the granular stuff has gone bad... any other explanation? All other tests have been good. I'm going through a bit more cl than I did last year, but I'm guessing that's due to CYA.
** testing with TF-100