OAKLAND -- Less than a year after John Balquist tried a sensory deprivation tank for the first time, he opened Oakland Floats, the new flotation tank center on 40th Street and Manila Avenue in the Temescal district.

For Balquist, the benefits of floating were immediate: The night after his first float, he slept better than he had in years, and in the weeks that followed, he experienced a surge of creative energy. The more he floated, the better he felt.

"I kind of got struck by lightning and just decided to go for it," Balquist said about starting his business.

The idea that you can float your way to relaxation and balance is striking a chord in today's fast-paced, hand-held society. People are snapping up Oakland Floats' Groupon and Living Social specials, and some days, the tanks are booked for every available hour. Users extol the benefits of floating in online reviews, and report feeling relaxed, calm and well-rested after a visit.

The original tank, invented in 1950 by Dr John C. Lilly, looked like a large hot water heater. The user was forced to wear an oxygen mask and had to insert herself into the tank like a bobbing human thermometer. Today, the design is a lot more easy to use. You can easily step into the tank and lower yourself into the ten inches of warm, Epsom salt-rich water. The floater lays back, totally buoyant, and soaks in complete darkness for more than an hour.

Lilly initially theorized that the brain would shut down completely in the absence of external stimuli, but he discovered the opposite was true. While the body can reach complete relaxation in the tank, the mind stays quite active and can even achieve a state normally experienced only during REM sleep, meditation, and just before sleeping or waking.

"All the research shows that your brain waves are slowing down to the theta state," Balquist said. "And they say that's the same state of mind you are in when you're right about to fall asleep."

For me, this all sounded excellent. If I could reach monk-like balance by spending 75 pitch-black-minutes floating in 10 inches of tepid salt water, well, count me in. As a person with a particularly stressful day job, the idea of physical and psychological relief sounded convincing.

I entered Oakland Floats and climbed the carpeted stairs to an open, sunny room with stencils of 20th century hot air balloons on the walls. The friendly receptionist led me to a softly-lit room, cozy like my aunt's guest room, where a large, futuristic, rectangular vessel waited for me. She showed me the towels and how to use the earplugs, and pointed me toward the bathroom.

This first visit to Oakland Floats was revelatory before I had even stepped into the tank. Freshly showered and safe in my robe, I knew that as soon as I had successfully shoved the waxy earplugs into my ears, I would strip down to nothing, climb into that enormous plastic shoe box, and float in a 93.3 degree soup containing 800 pounds of dissolved Epsom salt, in complete darkness, for 75 minutes.

Turns out that I'm a chronophobe more than a claustrophobe, because those 75 minutes scared the daylights out of me. Put me in a big, white, wet shoe box, no problem. As long as the door opens, I'm cool. But 75 minutes? Once I tried to meditate, and those were the longest seven minutes of my life.

I climbed into the salt water, adjusted myself supine, and immediately wished I hadn't scratched my scalp so vigorously the night before. Then I realized that my skin was nice and slippery and my shoulder was tight and sore, and I saw colors.

I floated three times at Oakland Floats, and found that by the third visit I had become almost audaciously confident in the tank, cracking joints and stretching and making myself float from side to side. I could also relax into semiconsciousness surprisingly quickly. Whereas my first visit was mostly trippy (I saw faces and shapes and occasionally wondered when I would be getting out), by the last float my subconscience was eager to take over.

Here's the thing about your subconscience: Sometimes, it may inform your brain and your body about what they actually need, rather than what you consciously think you need. After my second float, I started sleeping an inconvenient length of time every night, teenager-style. Eight hours of sleep was suddenly woefully inadequate, and I would pass out early and wake up late. I slept 12 hours each night for five days in a row. There's no doubt that I needed it, but it took the floating to force me to actually do it.

After just emerging from the dark calmness of a float, real life can seem disorienting. Getting dressed turns into a lengthy task, and those five new text messages from your boss feel especially heavy compared to your new state of lightness. For me, that was perhaps the most profound part of floating: It helped me judge the real weight of my life, and made me reflect on how much I should be forcing myself to carry.