I’ve been wanting to try a sensory deprivation tank since discovering them several months ago. For those unfamiliar, a sensory deprivation tank - also known as an isolation tank or floatation tank - is an enclosed tub of water about 8 inches deep containing 800 pounds of epson salt. This salt creates a buoyancy twice that of the dead sea. The tank is sound proof and light proof, essentially isolating the individual inside it from any external stimulation.

These tanks were invented by scientist John C. Lilly, who wanted to test brain activity in complete isolation. In doing so he created an environment that provides a unique and relaxing experience to both the mind and the body.

Here’s my experience spending 1 hour in an isolation tank at Chicago’s SpaceTime Tanks:

As a Christmas gift to my brother who was briefly in town, I booked us both 1-hour floats for the Saturday after Christmas. I booked them a week ahead of time and they were able to offer several available times. Some tips they shared upon booking:

Avoid shaving 3 hours before floating (salt water + cuts = ouchy). Avoid caffeine 3 hours before floating. Don’t be hungry.

Basically, the more relaxed and comfortable you are, the better.

Upon arriving we were immediately asked to take off our shoes. The reception area was nice and relaxing and had a calm/homey vibe to it. We filled out a short form with our information and then one of the employees escorted us into a room to give us a quick informational shpeal. After that we were off to our separate rooms which contained a shower and an isolation tank. I rinsed off, climbed inside the tank, and shut the door - I was in complete darkness and complete silence experiencing zero gravity.

The feeling of floating without using any muscles or effort at all is pretty incredible. At first I was focusing a lot on my breathing - listening to it (it’s all I could hear), trying to make it quieter, slower, calmer. Then I tried different positions with my arms (up around my head, down by my side, underneath my head). Each position had it’s own comfort appeal.

As my 60 minutes proceeded, many thoughts entered and exited my mind - goals, shortcomings, past memories, desires, accomplishments. I felt as if nothing else in the world mattered, that it was all controlled in my head. Anything outside of my head giving me energy I didn’t want didn’t matter because it could all be controlled in my head.

My time in the tank felt like a bunch of mini dreams. I don’t know if I was sleeping or not. I don’t know what you call the state I was in. I experienced some minor visuals including black blobs and the feeling of floating down a swift river. Weird.

I thought about my body and the way I treat it… how fragile, valuable and important it is. I thought about obligations I’ve been putting off, and people I should talk to. I thought about a lot.

Then I heard the knock on the tank signifying my time was up. It was over. It felt like 15 minutes but was an entire hour. I rinsed off, got dressed and re-convened with my brother in the reception area. We were both pretty amazed, and maybe a little confused about the experience. We spent a few minutes chuckling and reading through the “Float Journals” they have sitting on the table - notebooks customers write reflections in after floating.

For me, the flotation tank was a new level of relaxation, where both my mind and body were at complete ease. The tank was my own personal exploration pod - an isolated bubble of my own consciousness.