Is it all the same wherever you buy it? Walmart didn't have large qty's of solid CYA at the store, but found Blue Wave brand online at walmart.com thru Wayfair. Amazon also has the same product, and the one online review says it is junk. http://www.amazon.com/Swim-Time-7-lb...=cm_cr_pr_pb_i
Any reason not to save a few bucks and get this, compared to buying from the pool store?