I personally don´t like the salt baths, but as you read in some treads, it seem to be "the thing" in this forum, for everything people tend to use or recommend salt baths.
In my opinion and my experience there are always several things that you can do to help your axie, I had problems with my axies and never used the salt baths, and they are healthy, in the place that I work I take care of 15 adult axies and several larva and juvi,and never used salt baths , and belive me that I had my share of sick axies.
I´m glad that she´s not floating too much now, but if she is coming to the surface to gulp some air too many times maybe there is a lack of oxygen in the water.