The first flotation tank was pioneered in 1954 by a neuroscientist and psychoanalyst, John C. Lilly, while working at the National Institutes of Mental Health (NIMH). John C. Lilly was intrigued with what happened to the brain while deprived of all sensory information. Does the brain need external stimuli to keep its conscious state? Would our thoughts continue without any new incoming information?
Lilly and his associates set out to create a system that would restrict environmental stimulation. The first flotation tank was much different than today's, however they worked to strive to provide a sensory deprivation experience. Participants reported that following a float they had feelings of intense relaxation and calm, as well had experienced epiphanies of self-realization and personal awareness.
Lilly's curiosity was ignited and he continued his research over the following two decades. He began improving his flotation chambers and developed the "Samadhi" (refers to a profound state of meditation) float tank after partnering with Glen and Lee Perry. The "Samadhi" was the first tank provided to the general public. This flotation tank was easier for people, enclosed, and light-proof... and the new addition were EPSOM SALTS. This con concoction of salt and water is what's used today in float tanks. The concentration of salts creates an effortless, buoyant experience, counteracting the "sense" of gravity. The focus of today's float tanks is about offering a soundproof, lightproof and weightless environment for people to experience a reprieve from external stimulation/sensation. This weightless float allows the body to be more relaxed.