I was told by the local store that granular will harm my SWG and should switch to liquid which is quite expensive. So starting last year, I used the liquid and the cya level doesn't seem to stay. Some of the reviews from Amazon also said it doesn't do much. I used to add granular cya up to level once a year during the opening season and forget about it until the following year without any problem. Now I found a much cheaper place to buy the liquid (instead of the rip off price at the local stores) but don't know if I should switch back to granular. The only advantage for the liquid I see is just how easy to pour into the pool. I usually have to wait for the following week to retest the water anyway to instant dissolve doesn't benefit me.
Is there any truth to the harm to the SWG by using granular and does liquid cya work as well as granular?