We are working on the pool. Getting ready to install the CircuPool SI 45 Plus. I have noticed CircuPool requires salt to be 99% pure. I've been looking at salt where ever I am shopping this weekend. Sam's has Morton salt, it says it is for swimming pools with salt water systems($5.76/40 lb bag). Leslie's (I was there trying to get a new gasket for the pool light) has salt for pools($9.86/50 lb bag) WOW. I've looked over both bags and can't find purity information on either one. We asked the guy at Leslie's, if the supplier ever states the purity level and he said NO. Is this salt they are selling really good or bad? I don't know where to check next. Where else can a person buy half a pallet of salt? What do you guys out there do?