Nope, when indoors I just stir it once in a while, usually a couple times of day when I happen to be there to commune with the girls. Outdoors, the rez is pretty much on its own, I don't fuss with it.
I don't know whether an air stone would help. Others here have suspected that using one continuously can cause pH instability though, which is one reason why I have never bothered. As I recall, Cocoforcannabis recommends them, so I doubt that it would hurt to try as long as you watch the pH issue.
Good luck with it.