This simple answer? About 1,000 pounds of medical grade Epsom salt. This solution of Epsom salt (magnesium sulfate) is used to create a weightless suspension of your body, but also leaves your skin feeling smooth and rejuvenated. For thousands of years, millions have flocked to the Dead Sea for the relief from pain and muscle aches the salty water provides. Floating provides a modern-day way to experience the same relief.