i am using cya granules and have tried the sock method but i swear its still a 50/50! i had a cya of 21ppm it said to add 2lbs of cya up so i put 2lbs in a sock and put it in the skimmer basket came back a week later on my route and the cya is the same level! and the sock was empty but i did this at another pool and it worked just fine anyone know why?? might switch to liquid cya even though it cost more it seems more consistent and amazon had 4 gallons for $80 right now