We too added the solar salt to our pool and posted the results under Rangeball's thread on this. It was solar salt at $3.27 for #40 - 3 bags. This was probably 2 weeks ago. We are almost thinking of one more bag.

The water DOES feel great, hair/skin/eyes all benefit. The heat retention theory is interesting and makes me wonder....our pool sits around 84-88 these days, but then its been 80s one week, 90s another, now 80s......nights in high 50s, low 60s (one or two exceptions that were higher)