There's no sensation to speak of in this metal box filled with water. I may as well be in a casket at the bottom of the ocean, and yet this experience is supposed to bring me inner peace—maybe even enlightenment. Yeah, well, we'll see.

First things first. I'm in a Samadhi float tank, vintage 1985—lying in the basement of what looks like a massage studio. Unassuming as this beige-colored box is, it's what Portland "floaters" are using to access "the silent mind." In late June, the city's only commercial float business, Common Ground Flotation Center (part of the Common Ground Wellness Center complex), reopened after a 10-year dormancy, offering clients the opportunity to float naked in a lightproof, soundproof tank, buoyed by 800 pounds of Epsom salts dissolved in warm water at around $50 a dunking. The experience has proven so popular among stressed-out Stumptowners that in mid-September, the facility's owner, chiropractor Elliott Mantell, purchased a second float tank to accommodate the demand.

Why floating, why now? "With war going on around the world, now is the time for healing..." says the center's manager, Katie O'Neill. She says the tanks function as antidotes "to the communications and technology revolution" by allowing floaters to tune out.

"It's like a week's vacation in an hour," adds Mantell, a lanky man with casual posture and serious eyes.

My skepticism toward sensory deprivation, like many people's, stems from the so-bad-it-was-good 1980 film Altered States, starring William Hurt as a Harvard physiologist who doses himself with hallucinogens, holes himself up in a tank and genetically regresses into a hairy, bloodthirsty proto-human. The film was based on Paddy Chayefsky's novel of the same title, which in turn was very

loosely based on the research of tank inventor and LSD experimenter John Lilly. When it came out, Altered States sparked a short-lived craze for floating.

These days, turning into a Neanderthal doesn't number among the fears floaters harbor, although many do worry about drowning or suffocating—fears that staff members allay. The tank is 8-by-5 feet, filled with 10 inches of water maintained at 93.3 to 95.3 degrees—the average temperature of human skin. Heating the water to that temp makes the perceived border between the body and the water disappear. The floater's eyes and nose remain above water, the ears below. Fresh air circulates, and there is no lock on the lid.

The reasons people float at Common Ground vary. William Wright, a 23-year-old college student, finds that the experience helps him "get better at being less obsessive with negative thoughts." Jonathan Klein, 31, was diagnosed five years ago with multiple sclerosis, a condition "that leaves me extremely worn out—there are certain muscles in my legs that are always tight." Klein has gone into the tank four times. "When I float, it removes the pull of gravity, so my body is able to rest and relax completely," he says, "something I can't do when I'm not weightless." Maureen Addington, 50, says that while she's tried all manner of alternative therapies on the path to self-exploration—from acupuncture to Buddhist meditation—she finds floating the most satisfying. "Not having the senses is kind of like dying, in a way," she relates. "There's a kind of beautiful annihilation in that deep silence."

Intrigued, I finally decided to give this floating thing a try. As the staff recommends, I prepped with a sauna and 30 minutes of AVS (audio-visual stimulation), a headphone/sunglasses contraption that droned low-pitched tones while flashing lights. This provided some trippy imagery—a sunrise over the ocean, a shining green footprint—and left me surprisingly blissed out, despite the fact that I'd resisted the urge to consume questionable substances beforehand. (The center makes clients sign a release affirming they're not on psychoactive drugs.)

After the AVS, I descended into the tank. There was a "gee-whiz" moment when I climbed in, pulled the lid shut and lay back as if upon the Dead Sea, my feet and butt lifting up, my neck and head cushioned naturally by the water's buoyancy. For the first 20 or 30 minutes, my mind wouldn't stop. I rehashed career issues and relationship problems. I thought about other things, too, which sound hokey in the light of day: the symbolism of venturing back into the womb, and of drifting beneath an entropic night sky devoid of stars.

I became hyper-aware of my body, silky-slick in the viscous brine. At a certain point my muscles twitched a bit, the water rippled, and I realized I had gone to sleep. Noting this, I fell asleep again. I have no recollection of my dreams, nor any idea whether the float helped my mind process the baggage I'd taken into the tank. I do know that when soft music began playing through the tank's speaker to wake me, I heard it from a place so distant, it seemed this music was the first I had ever heard; and when I opened the lid to re-enter the daylight, it felt like a sort of rebirth.

No doubt, this line of corny observation is just what you'd expect from someone freshly emerged from the hippie-dippy uterus of a float tank—and so is the next thought that entered my mind as I toweled off: that I couldn't wait to go back in again.

Common Ground Flotation Center, 2917 NE Everett St., 232-6161.$35-$80. Call for rates.