Use a nylon instead of a sock, allows for more water flow in and through the CYA. Cotton socks are often too thick. The point of the "sock" is to keep the CYA in one place while it slowly dissolves, not to impede the dissolution.
Hang the sock in front of a return in the larger pool volume, it works better that way. I use a 3/4" PVC pipe to tie the sock to and some decorative rocks on the other end to secure it in place.
Finally hot water dissolution can work but it doesn't really change the solubility a whole lot. If you're really need CYA fast, then use liquid CYA. It's more expensive but you'll get faster results with it.