I have been using dead sea salt, pink Himalayan salt and Epsom salts and baking soda (equal parts of each) since last spring with wonderful results. I soak 20 minutes or longer sometimes 3-4 times a week. I add essential oils, lavender, rose and store them in a huge glass jar in the bathroom. I noticed it has helped quite a bit with my fibromyalgia and arthritis. Sometimes I will use bentonite clay aka Montmorillonite for other baths. I found a little book on amazon called "Not Just a Room With a Bath" by Dr. Keith Souter published in 1995. I found it helpful. It lists the different things that can be added to a bath and what the benefits are as well as bath remedies. I am still searching for that perfect bath book that lists everything for every aliment!