I have the typical above ground spa. I couldn't find anything on the forum, so here you go.
1) Can I convert to usiung salt water for my spa?
2) Is there any special equipment?
3) Would you recommend it? Advantages and Disadvantages.

Available for cool swimming pool water.....don't know of any that work on hot spa water.

I see three available through spa net. they are costly. Anyone had any luck with them.
if price comes down seems cool.
Salt could cause more rust?
Ph might be shifty?
I'd like to hear more.