I had 50-60 ppm of CYA in the pool last year when closing; drained maybe 1/6 of the pool so was expecting to open with 50ppm. I've opened this year to 0. I double checked my method and my reagents with the 50ppm calibrated sample from tftestkits and it's definitely gone.
I'm going to use dichlor to raise the CYA level as I'm currently SLAMming with bleach, but dichlor will work just as well and will also give me pretty instant CYA.
Any thoughts about this process? IIRC CYA isn't supposed to just "disappear" without draining all the water and starting again, so I guess something has used it up, but I've no idea what.
Any opinions on a better method to SLAM and increase CYA at the same time than dichlor?