Mill Valley Flotation Tank

Association for
Cultural Evolution

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Mission &
Board of Directors






Who's Who Listing

John C. Lilly, MD.

Ruth Forbes Young

Richard Feynman




P.O. Box 2382
Mill Valley, CA 94942 USA

T: (415) 409-3220

Floatation Tanks

Interested in Floating?

Check out FloatSpace for more information about our Mill Valley flotation tank and how you can use it.

History of the Tank

Does the Brain Need Stimulation?

When: 1953

Scientific Question: What happens if you remove the stimulation of the outside world?


Many scientists wondered what would happen if a person were cut off from all sensory stimulation and from interactions with the world outside. Scientists influenced by the "behaviorist" school, thought of the brain as an organ that reacts to stimuli. They predicted that if all outside stimuli were cut off, the brain would cease its activity resulting in a condition resembling coma, or dreamless sleep.

An alternate hypothesis was that in a state of profound isolation from stimuli and interaction with the world, the brain would continue operating and generating experiences.

Dr. John Lilly tested these hypotheses with experiments he set up at the National Institutes of Mental Health Lab in the Virgin Islands. He limited stimulation to the minimum possible level while removing sources of discomfort and stress. His "isolation" tank design approached this ideal as closely as possible and the experiment was up and running by the end of 1954.

John C. Lilly MD, the tank's inventor

The First Isolation Tank Work

In the isolation tank, Dr. Lilly found that he could relax his mind and dream, but his consciousness was always there, ready to take charge. He could choose to relax and let things happen, in which case the images would free-associate, moving as if randomly from one to the next. Or he could choose to program what would happen, in a process similar to lucid dreaming, but with an even greater degree of control. He could invent a scenario ahead of time with his consciousness fully focused, and then relax and let his brain carry out the program.

The Principal Discovery

The important discovery was, "So within yourself you do have at least the circuitry to exert control over these systems. You can create a sense of well-being, or you can create a sense of fear out of the operation of your own bio-computer. That's the most important message we have in regard to self meta-programming. I saw that in the tank."

"Somewhere, deep within the brain, was a mechanism capable of generating internal experiences completely independent of the outside world, and this settled the issue of what happens in profound physical isolation. The mind does not pass into unconsciousness, the brain does not shut down. Instead, it constructs experience out of stored impressions and memories. The isolated mind becomes highly active and creative. This was the principal discovery that Dr. Lilly reported in his first three scientific papers on the isolation tank research, published in 1956, 1957, and 1958."

The First Major Group - the Exteriorites

"Lilly sees the tank as having two major uses. One is for individuals who are satisfied with and thoroughly tied into modal Western concepts about the relationship between the individual and the external world: that is, for whom the external world is the only reality, and for whom the internal world of imagery and fantasy is perceived as something unreal. If the individual is satisfied and content in this mode, the isolation tank can be used as a place to consider one's problems and work out solutions with a minimum of distraction...."

Consciousness Seekers

"For another group of people, the distinction between external circumstances and internal processes is not so clear-cut. They perceive both sets of phenomena as partaking of the quality of realness. These people may be interested in self-analysis, meditation, transcendental experiences, and altered states of consciousness. For them, the isolation environment is useful because it minimizes interactions with the external reality and allows the internal domain to be more fully explored."

Promise or Possibility

Author Michael Hutchinson in "The Book of Floating" speaks well here. "A new tool has been developed that, like the computer, has the potential not only of bringing about enormous increase in our capabilities as individuals but also of fundamentally changing our way of life as a society.

This tool is the floatation tank, an enclosed chamber filled with approximately ten inches of warm saturated solution of Epsom salts. A solution so dense that even the thinnest person floats supine with the entire body at or near the surface of the water.

The buoyancy counteracts the effects of gravity, giving the floater a sensation of weightlessness. The chamber is pitch-black, silent. In the absence of sensory input, the floater feels detached, free, at peace, Most floaters report enhanced mental powers. Virtually everyone finds the experience immensely pleasant. And, as one prominent scientist says, the tank provides a method of attaining the deepest rest that we have ever experienced."

Samadhi History

Samadhi Tank Co., Inc.was started in 1972 and named by Dr. Lilly. The first tanks were designed by Glenn Perry with Dr.Lilly's assistance.

In 1972, Glenn Perry a preposterous computer programer read "Center of the Cyclone" by Dr John C. Lilly, took a workshop with Dr. Lilly and turned his life around. Until then, Glenn's view of reality conformed to the traditional, Western, scientific model. In a very short time, his point of view expanded, allowing him to consider, examine and even adopt adeas and thoughts that were not necessarily "provable".

From Shyman to Business Tycoon

"At that time I was working at Xerox, in a department with two other programmers. I could relate to either one of them individually, but if the three of us went down to the lunch room, I would be quiet. I was just too shy to talk to two people at once. So the first time I used the tank, John asked me to talk about my experience, and I was able to speak to the group without nervousness. If the tank could let me do something like that, it is something really incredible.

My whole experience of leaving the tank aftere my first session was fabulous. The whole world was a shimmering, shining dance. I had to make a tank for myself, and being naive, thought that with just a little extra work I would make them for others."

When I built the first tank, Dr Lilly had given me some design pointers based on the two or three tanks he had built. In fresh water you'd bend your legs at the knees, and you'd inhale and hold your breath, and when you needed to take a breath you'd exhale and inhale quickly and hold it. That's the way you floated. This is the way dolphins breathe - their breathing is not automatic, but intentional. So whenever they need a breath, they come up to the surface. I don't float in fresh water because I'm thin. Dr Lilly mentioned that I could add 3% salt so I could float more easily. I went up to 10%, and set up a tank for him. When he experienced the 10% salt, he suggested taking the solution up to saturation, or just this side of it, so we could float as well as possible. He suggested using epsom salt instead of sea salt, since sea salt seemed to be a little bit harsh on the skin. This happened in 1973.

Dr. Lilly encouraged our work with the tank. He spilled lots of wisdom on us, gave us the specifications, gave us the program that we shouldn't program people before they used the tank, (and admitted that was his program), he gave us the name "Samadhi" and a lifetime of work which we greatly appreciate.


Before You Float

The Samadhi Orientation

The following is what we tell people before they go into the tank the first time. This is what we say:

I'm going to talk to you

"I'm going to talk to you about the tank for a few minutes. I will include the things we have found most people want to know before their first float.

Many people have some fear or concern before they use the tank the first time. Fears such as being alone in the dark, drowning, not having enough air, claustrophobia, and others. The fears are usually the thought or the idea that YOU won't be in control of the situation, but in this situation you are totally in control. You can go in and out of the tank as you please. You can use the tank with the door completely open, you can keep it partially open, or you can close it. There is no particular way to use the tank that is more correct than another. Any way you use it, that is comfortable for you, is correct.

When you get to the tank, open the door just to feel the weight of it. It is very light. If you close the door while inside the tank, it is completely dark and that may be disorienting. When you get in and before you lie down, open and close the door several times, noticing how it feels different from the other surfaces . If you try to open the door and it doesn't open, it's not the door.

The Tank is Not Airtight

The tank is designed so that it is not airtight. You'll have plenty of air. To keep the tank air fresher, an air circulation system brings additional air from the room. The air enters at the rear of the tank. You may prefer to have your head at that end.

800 Pounds of Epsom Salts

The tank environment is humid. There are 10 inches of water in the tank with 800 lbs. of epsom salt dissolved in it. When you lie back you will float like a cork. Your ears will be under water. There are earplugs available if you would like them, and we recommend them if you have ever had ear problems.

Buoyant Body Positions

You can experiment with the best body position for you. For example, hands behind head, on your chest, along your sides. If you have tension in your neck you can relieve it by clasping your hands behind your head or using a head float.

Keep the Salt Out of Your Eyes!

If you get any salt water in your eyes you will be uncomfortable for a few minutes. To avoid getting drips of salt water in your eyes, push your hair back on your forehead when you change from lying down to sitting up. Also keep your salty hands away from your eyes. If you do happen to get salt in your eyes, have your towel where you can easily reach it, and use it to wipe your eyes.

More Ouch!!

If you have cuts or scratches or have recently shaved, there may be stinging for several minutes. If you have any open cuts use liquid bandage to seal them.

Last Stop Before Boarding

Remove your metal jewelry and contact lenses. Shower, shampoo, rinse thoroughly and dry your face before you get in the tank.

The End

Then get into the tank. After an hour passes a signal will let you know your time is up. A few minutes later, the filtration system will begin cleaning the tank. Some people don't hear the signal and if you don't hear it, you will feel the gently moving water as your signal to get out. Sit up, stand and squeegee the solution from your body before getting out of the tank. Step directly into the shower or tray whichever is in front of the tank.

Housekeeping Care

Your body has salt water all over it which you don't want to drip everywhere. If you have to walk to the shower, towel dry thoroughly. Shower, shampoo well, and dress. The bathroom has the amenities you need.

Reflects Your Life

At the beginning of each float you can set an intention for what you would like to accomplish during your float. You may also use your float to observe where you hold tension in your body or your mind. You will develop many of your own ways of using your floats. We don't say more because we don't want to spoil your own adventure.

Enjoy your float and check with your guide for any additional information.


"When I bought the tank I expected to have experiences similar to those that Dr. Lilly writes about. When I finally got into the tank, all I found was those expectations and nothing more. No visions, no 3D objects before my eyes, no leaving my body, no other entities, no infinite space, no nothing. At first it was quite a shock, but actually, this is what the tank is all about - revealing to you your own assumptions, which are usually so implicit that you don't even know they are there."
George P.

Lee, the president Lee, Samadhi president

Frequently Asked Questions

FAQ - Before Using

Do I need to prepare myself for floating?

The things you should know are:
a) If you shave 2 or 3 hours before using the tank, the shaved skin will sting for a few minutes. If you can postpone your shaving, you will probably be more comfortable.
b) If you wear contact lenses, it would be a problem if any salt water got into your eyes. If you remove your contacts you don't have to be concerned about it.
c) If you have caffeine before you float, it may interfere with your ability to relax.

Should I eat before I go into the tank?
You can eat. If you eat a very heavy meal you may spend a lot of time listening to your digestive juices. And, on the other hand, if you get very hungry you may spend a lot of time listening to your digestive juices. Moderation works.

FAQ - Who Can Use

Is there a typical tank user?
Not that we know of. People of all ages and walks of life seem to enjoy the experience equally. What seems typical is how good everyone looks when they come out of the tank.
Is anyone not supposed to use the tank?
We don't recommend tank use for epileptics whose epilepsy is not under medical control; for people under the influence of alcohol, drugs, those with infectious diseases, open skin wounds, or those with suicidal tendencies.
Can pregnant women use the tank?
Yes. We suggest that pregnant women inform their physicians or midwives and get their opinion prior to using the tank. The reports received from pregnant women have been enthusiastic. As their bodies get heavier, floating is a great relief from the pull of gravity. Floating has given many women a welcome rest.
Can I use the tank if I'm menstruating?
Yes, if you use a tampon.
Do children use the tank? What is their response?
Yes, we know that children use the tank and we don't know much about their responses. A 7 1/2 year old came to a public center with his mother. He listened to the orientation she was receiving. When he heard about the fears, he said he was very afraid of the dark. Later, when he used the tank, he was asked about the fear of the dark. He said that was a different dark. Night time dark was scary and full of dragons, and the dark of the tank was friendly and nice.

FAQ - Physical Concerns

What effect does salt water have on my skin and hair?

The Epsom salt solution seems to be beneficial to the skin. We have listened to some opinions that say epsom salt is very good for strengthening the hair. We know it's good for roses, why not hair? You thoroughly rinse the salt from your hair and body when you leave the tank.

Can You Wear a Bathing Cap?

Yes, you can wear one, but it won't keep your hair dry. It would be too tight around your head to keep you hair dry.

Do you wear anything in the tank?
Since it is a private experience, most people don't wear anything. Anything you wear will press against your body, becoming a distraction. In this regard imagine it as similar to getting into your bathtub.

Do people sleep in the tank?
Yes, some people fall asleep in the tank, and some people use the tank for sleeping.

Is there a right way to do it?
All the ways are right. Each person should find whatever position is comfortable for them. Some people float with their hands at their sides, some with their hands folded across their chest or abdomen, or behind their heads. You can keep your head at either end or sit up if you like. You may float with the door open or closed. Float the way it is comfortable for you and explore what is best for you.

Will I float? I can't float anywhere.
Yes. It is impossible not to float in the tank. Eight hundred pounds of salt dissolved in the water make the solution so much denser than your body that your body is pushed to the surface like a cork. Your face is out of the solution and your ears are underwater.

Can people drown in the tank?
No. Not unless they lay face down in it, and are capable of tolerating the sting of the salt on the eyes, nose and mouth.
Could you get electrocuted?
What if I'm claustrophobic?
People who say that they are afraid to use the tank because they are claustrophobic probably assume that they will be confined to an enclosed space. However, you can use the tank with the door open if you wish. You are in control of the situation and can get in and out when ever you want. You should use it in the way it's comfortable for you. The tank is such an excellent place to go through claustrophobia that if you want to get rid of yours, it is probably the best place to do it.
Is it dangerous to sleep in the tank?
No, It is safe to sleep in the tank. The reason people think it may be dangerous is probably the fear of rolling over. Even those people who say they never sleep on their backs in bed, sleep on their backs in the tank. It is very difficult to roll over in the tank because of the density of the solution, and if any of the salt solution gets in your eyes, mouth or nose, it is an immediate signal that something must be done.You would wake up immediately.
Is there enough air in the tank?
Yes. The tank is designed not to be airtight, so there is a plentiful air supply. In addition, fresh air is brought in by an air circulation system.
Can two people float in the tank at the same time?
We don't recommend it. Floating in the tank is intended to be a private, individual experience.

FAQ - The Nature of a Float

How long do people usually stay in the tank?

The first time public places usually schedule an hour.Some people use the tank for shorter sessions and others find 2 or 3 hour sessions very valuable. Of course the "perfect" way is to stay in until you want to get out. You may be able to arrange that in a public place.Experiment with your own time in the tank to discover what is best for you. One of the many advantages of having your own tank is that you can set the amount of time that is best for you without any restrictions.

What will it be like for me?
We don't know what it will be like for you since it is such an individual experience. The most common reports are profound peace and relaxation, deep concentration and creativity.
We like to avoid saying too much before people use the tank, so that they aren't influenced by what someone else says. Not only will it be different for you than it is for anyone else, it will be different each time.

Do I need to float more than once?
Yes, if you want to make use of the potential. For us floating is not a finite experience. It touches the infinite. Most people, but not all, get a sense of what floating will be like after they float 3 to 5 times.Those who see the potential the first time, want to return again and again.
Is there a best time to use the tank?
No.This is a matter of individual preference. Some people prefer morning, some prefer night. The best way to find out is to experiment by using the tank at different times of the day.

Will I be able to resume my daily activities when I get out?
Yes. And it may be good to arrange your time so you don't have to rush. Many people enjoy savoring the peace and quiet before jumping into something hectic.
Is there a cumulative effect of using the tank on a regular basis?
Yes. There seems to be a cumulative effect with consistent use of the tank. This is not documented by research, it is the tank users who know it is true. Relaxation is a learned art that needs practice.
Is this sensory deprivation?

The term "sensory deprivation" describes areas of scientific research that consider the effects of reduced environmental stimulation. The words are an unfortunate choice for those of us who are presenting the floating experience as something pleasant, attractive and relaxing. We notice that people run away from us when they hear the possibility of any form of deprivation. As a result we are careful to point out that the senses are fully operational and in fact, the senses are very pleased to be relieved from the prevalent atmosphere of sensory overload. Stimulus reduction is an accurate description of the tank environment. For more information about sensory deprivation.