As you float weightless in the darkness, your mind begins to wander. Your breathing slows, and your thoughts quiet as you sink into a state of meditation. These sensations might not occur for all visitors to the isolation tanks at SpaceTime Tanks Floatation Center, but there's a good chance the process will at least help them relax. Technicians start by filling each eight-foot tank with 10 inches of water heated to the average temperature of human skin. Then they add 800 pounds of Epsom salts to the mixture so that the human body floats effortlessly on the water's surface. Between each session of blissful sensory deprivation, the technicians sterilize the ventilated tanks with a mixture of ozone, hydrogen peroxide, and diatomite earth filters.

Outside the tanks, the staff eases customers' tension with more hands-on techniques such as Swedish and deep-tissue massage. They can also fit clients with headphones and LED light goggles for light and sound therapy, during which rhythmic visual and aural stimulation synchronizes brain waves to basic mental states, such as relaxed wakefulness or sadness that Friends is over. Building on the idea of soothing sound, the NexNeuro system uses motion, acoustic vibration, and music to promote calmness.