Float Tank FAQ

FAQ about the float tank experience

Frequently Asked Questions about Isolation Tanks

“An isolation tank (float tank) is a lightless, soundproof tank inside which subjects float in salt water at skin temperature. They were first used by John C. Lilly in 1954 to test the effects of sensory deprivation. Such tanks are now also used for meditation and relaxation and in alternative medicine. The isolation tank was originally called the sensory deprivation tank. Other names for the isolation tank include flotation tank, John C. Lilly tank, REST tank, float spa, sensory attenuation tank, and think tank.” [1]

1. Definition

a. What is a float tank?

“An isolation tank is a lightless, soundproof tank inside which subjects float in salt water at skin temperature. They were first used by John C. Lilly in 1954 to test the effects of sensory deprivation. Such tanks are now also used for meditation and relaxation and in alternative medicine. The isolation tank was originally called the sensory deprivation tank. Other names for the isolation tank include flotation tank, John C. Lilly tank, REST tank, float spa, sensory attenuation tank, and think tank.” [1]

Float Tanks come in different shapes and sizes depending on the manufacturer. The float tank, or sensory deprivation tank, resembles an over-sized enclosed bathtub in which the bottom of the tank is filled with 10-11 inches of water that has been saturated with 800-1000 lbs (360-500 kg) of Epsom salt (magnesium sulfate).

The sensory deprivation tank experience is meant to provide an ideal environment for the floater; free from light, noise, and touch floating allows specific areas of the brain to engage in healing, self-improvement, and creativity. The salt water and air inside the chamber is regulated at a temperature of 95.9 Fº (35.5 Cº), the same temperature as the surface of your skin. The chamber is designed to be completely dark and ear plugs are provided to the floater.

b. What are they used for?

Over the last few decades this integrative healing tool has been scientifically studied and applied to many areas of human development. Isolation tanks have been shown to improve health without the use of drugs, which has sparked interest in the field of medicine. The destressing and increased rate of recovery has made the floating experience very appealing to fitness enthusiasts and trainers alike. Sports teams like the Dallas Cowboys, Philadelphia Eagles, and many Olympic contenders have been known to use the isolation tank to improve their athletic performance.

The sensory deprivation tank creates an environment free of all distractions enabling the body to truly relax. In this deepened relaxed state the body’s natural abilities to heal, focus, and harness creativity are heightened. This makes floating a powerful learning tool for any student, artist, or person looking to get the most out of their profession. Some celebrities that have utilized floatation tanks are: John Lennon, Robin Williams, Jeff Bridges, Burgess Meredith, Carl Lewis, Kris Kristofferson, Susan Sarandon, William Hurt, Peter Gabriel, Kirk Douglas, Neil Young, and George Carlin (see full list of benefits below).

c. Do they have other names?

Yes: Sensory deprivation tank, float tank, floatation tank, isolation tank, floatation therapy tank, REST tank, float spa.

*see History

d. Is it hard to do?

No. In fact, the less you do the better. The only obstacle is allowing the body to fully relax the neck and shoulders into the Epsom salt solution. The buoyancy of the salt water keeps your body afloat like a cork. Know that the water only reaches the temples leaving the eyes, nose, and mouth fully exposed.

Some floaters choose to completely clear the mind of any thoughts. Others choose to actively direct their mind’s energy towards specific goals. For example: one may have a power-point presentation to deliver at work and may be experiencing stress and anxiety. Or, there may be a particular ailment you’d like to address which makes visualization techniques a very effective tool.

It may take a couple float sessions to get the hang of it. However, some people have the ability to get into a meditative state rather quickly. The body simply relaxes to the fullest and the mind clears along with it, consciousness is free to be in its original state.

e. What is it made to resemble?

The sensory deprivation tank is said to resemble the perfect state which we last experienced in the womb. In this state of relaxation, there is heightened brain wave activity which allows the floater to look inward. This introspection can be very productive for the floater. Feelings of serenity, inspiration, and creativity are common when fully relaxed in the float tank. Once fully relaxed, most people report a feeling of “floating in space” and “oneness with the universe”.

f. Is it necessary?

Yes. In a fast paced world it’s very easy to neglect our health. Our bodies are exposed to excessive stress forcing us to operate in “fight or flight” mode on a daily basis. However, when the stressful stimuli and sensory nutrients are removed from the environment, like in an isolation tank, cortisol stress hormone is reduced. The brain focuses on healing and higher consciousness. Floating gives back that well-needed time for recharging the body.


2. History

a. Who invented the float tank?

In 1954, John C. Lilly, M.D., invented the first float tank, which was simply an 8 foot cube filled with ocean water. Completely submerged, wearing a mask with oxygen, he used this prototypical tank to further his exploration of the limits of human consciousness.

By the late 1960’s, Dr. Lilly had the idea of floating in a supersaturated solution of epsom salts. This solution was found to be non irritating to the skin, while at the same time buoyant enough to keep the body naturally at the surface of the water, eliminating the need to wear an oxygen mask. By completely enclosing the water, maintained at skin temperature, Dr. Lilly was able to create a unique environment for meditation and scientific research..

“By attenuating vision, hearing and the proprioceptive sense, and floating at the surface so that the gravitational field is reduced to the minimum, you can relax every single muscle. Even your ear muscles, your neck muscles, your hands, your arms, your back, and so on. You can find the areas where you are holding needlessly, and you can let go. Once you do this, and go through all this, and get the inputs to the brain down to the minimum possible, you suddenly realize that that is what has tied you to consensus reality, and now your free to go.”

“The first thing you get is physiological rest. You’re free of gravity; you don’t have any more of those gravity computations that you do all day long. Finding where gravity is, and in what direction, and computing how you can move and not fall takes up about 90% of your neural activity. As soon as you start floating you’re freed of all the gravity computations you’ve been doing all the time, so you find you have a vast piece of machinery that was being used for something else and you can now use it for your own purposes. For example, you can instantly feel that you are in a gravity-free field. It’s as if you are somewhere between the moon and the earth, floating, and there’s no pull on you. As soon as you move, of course, you know where you are, but if you don’t move, your environment disappears and, in fact, your body can disappear.”

(John Lilly, from Tanks for the Memories; Floatation Tank Talks, by Dr. John C. Lilly & E.J. Gold.)

b. Who is John C. Lilly?

He is the father of sensory deprivation tanks. He was a medical practitioner and a neuro-psychiatrist.

c. What sparked the idea of John C. Lilly tanks?

When studying psychoanalysis at the US National Institute of Mental Health (NIMH) in the 1950’s, John Lilly and his associate Dr. Jay Shurley M.D., were interested in the origins of conscious activity within the brain. They wondered if the brain needed external stimuli to stay in the conscious state. This sparked the first experiments with sensory deprivation. J.C.L. tested the absence of stimuli on the brain by creating an environment completely and peacefully isolated- the first isolation float tank was born. Subjects would float upright, in a vertical tank, with a breathing apparatus and mask covering the head. Over the years, through trial and error, he was able to improve upon the tanks design. Subjects now float horizontally on an Epsom salt solution, without the distraction of a breathing mask, allowing for the deepest state of relaxation possible.

d. Have other scientists tested the therapeutic benefits of floating?

Yes. In the late 1970′s Peter Suedfeld and Roderick Borrie performed experiments with sensory deprivation. They named their technique “Restricted Environment Stimulation Therapy” AKA R.E.S.T. In 1982 the International REST Investigators Society (IRIS) was formed which gave scientific researchers the network to share their findings. Since the 1950’s, scientists around the globe have experimented with sensory deprivation to aid in couples counseling, children with autism, visualization for improved athletic performance, recovery from injuries, and rehabilitation.


3. Usage

a. Why Epsom salt?

Epsom salt is used to give the water enough density to float effortlessly with the eyes, nose, and mouth still out of water. Epsom salts have a plethora of health benefits (detailed explanation FAQ# 6c). It helps replenish a common malnourishment in today’s diet, lack of magnesium. It is absorbed from the salt, through the skin, without any risk of an overloading effect.

b. Should I shower before and after floating?

Yes. To extend the life of the filtration system showering beforehand is extremely important. Using the shower afterwards is also suggested to remove the coating of Epsom salt that is left on the skin and hair.

c. What is typically worn during a session?

This depends on the type of filtration system the float tank has. Some filters are only designed to handle hair, skin flakes, and bacteria. Lint from clothing stresses the filtration motor. Most bathers choose to bathe nude anyhow, because swimsuits can create uncomfortable compressed-stress points on the skin while floating.

d. How do you stay centered in the tank?

Some float tanks have a heating ring system which lines the perimeter of the tank in order to warm the water. As a result, the warm water rises on the outside edges of the tank, then travels towards the center, then sinks under the floater helping to keep her centered.

e. How long do people usually float for?

For the first time, most public places usually schedule an hour long session. Others find 2-3 hour sessions valuable. But the most ideal way is to stay in until you feel you are ready to get out. Experiment with the times and you will find one that best fits you.

f. Is there a best time and way to float?

No to both, it’s all personal preference

g. Do I need to float more than once?

Yes, if you want to make use of floating’s full potential. Most users understand floating’s benefits after the 3rd or 4th float. Those who see it after the first time are immediately hooked.

h. Will I be able to resume my daily activities after?

Yes, many people enjoy savoring peace and relaxation before having to do something hectic or tedious. However, some first time floaters may experience a “detox effect” as a result of the detoxification power of the Epsom salts. Take note that the detox effect can leave one feeling fatigued so first time floaters plan your day accordingly.

i. What makes this sensory deprivation?

Sensory deprivation is the scientific study of the effects of reduced stimuli, on an organism, in an environment. Stimulus reduction is accurate in describing the tank’s environment. The tank is pitch black which eliminates the sight stimulus. Ear plugs are provided to the floater which eliminates the audio stimulus. And, the buoyant, warm Epsom salt water helps eliminate the sense of touch and force of gravity on the body.

j. Do I need to prepare myself for floating?

Most float spas provide ear plugs, soap, shampoo, and a towel for your convenience. Keep in mind, if you shave 2 or 3 hours before using the tank, the shaved skin will sting and distract you from achieving deep relaxation. So postpone shaving until after the session. If you wear contacts, it would be in your best interest to remove them before floating.

k. Should I eat before floating?

Recent anecdotal reports show that eating a light meal about 30 minutes prior to floating is best. A heavy meal beforehand is not suggested. However, you don’t want to hear your stomach growling while you’re trying to relax. Moderation is the key. Also avoid caffeine before floating for it may interfere with your ability to relax.

l. If I have a cut or scratch, how could I float without irritating it?

A band-aid will come off in the water but liquid bandage would be acceptable if the float spa allows. However, it is not recommended to float if you have an open wound in the process of healing.

m. When the float cycle is over, is there a procedure?

Step into the shower to rinse off the salt solution. It is recommended to enter the world slowly after being exposed to the sensory deprived environment. Give yourself about 15-20 minutes to regroup.

n. Can I use the tank when menstruating?

Yes. Floating has been shown to relieve the symptoms associated with menstruation. It is recommended to us new feminine products during the float, and replace after as well.

o. How do I know when the cycle is over?

There will either be an alert at the end of the cycle or you will be informed by a float spa specialist. If you happen to sleep through this, you will hear the filtration system turn on inside the tank.


4. Users

a. Is there a typical tank user?

There are no typical float tank users. People of all ages and walks of life enjoy the experience. (refer to question 1-b.)

b. Is anyone unable to use the tank?

People under the influence of drugs or alcohol, and those with infectious diseases are not suggested to float in a sensory deprivation tank. Those who are epileptic, and NOT on controlling medication for the condition, should avoid using the tank as well. And, if you are in your first trimester of pregnancy, floating is not recommended.

c. Can pregnant women float?

Yes, women within their second and third trimesters and only after clearance from their physicians or midwives. Pregnant woman probably get more relief from floating than most people. The extra weight carried by the mother-to-be can be very stressful due to the forces of gravity. Floating eliminates the negative effects of gravity which can cause joint pain, inflammation, and stress on the organs as well as the unborn baby.

Pregnant woman have also reported a reduction of erratic movements of the baby inside the womb. This is due to a phenomenon called the “mirror effect”. The baby is safe and secure inside the womb and the mother shares a similar experience in the warm isolation tank. Woman report a stronger connection with their baby when exposed to this environment.

d. Do children use the tank? What is their response?

Yes, although there is little documentation of their responses. Children have found it easier to dismiss their fears of being in a dark, enclosed space after only a few sessions of float therapy. Further research is being conducted on autistic children and the affects of Restricted Environmental Stimulation Therapy (REST). It seems that sensory deprivation provokes positive changes in learning, social behavior, and cognitive function in autistic children.


5. Benefits

a. What are the benefits of floating?

  • Enhance your learning capability i.e. concentration, memory, and focus
  • Improve sleep patterns
  • Normalize blood pressure
  • Enhances ability to stay focused and concentrate
  • Unlock the creative centers in your brain
  • Destress and relaxation
  • Aids in helping people quit smoking
  • Helps reduce cortisol related weight gain
  • Increases athletic performance (energy, stamina, strength, quicker recovery)
  • Achieve effortless visualization
  • Increases your body’s ability to detoxify with the mineral rich salt bath
  • Strengthens immune system
  • Improve skin tone
  • Helps release endorphins-the body’s natural opiates
  • Pain relief from injuries/ailments
  • Eliminates the pressure of gravity allowing the body to free up healing energy
  • Helps the brain produce theta waves which are mirrored in the advanced art of meditation. Theta waves promote productivity, creativity, and a sense of inner peace or enlightenment
  • Creates an environment for meditation and lucid dreaming
  • Stimulates right brain activity which allows us to absorb and learn information on a larger scale.
  • Helps reduce addictive behavior
  • Aides in female fertility
  • Helps balance hormones
  • Alleviates symptoms of depression and anxiety
  • Reduce migraines
  • Relieves inflammation in joints
  • Improves spinal issues
  • Increase magnesium absorption

b. What explains these benefits?

i. Based on the research of 40 minute float sessions, floating in an isolation tank can reduce levels of the stress hormone cortisol*. This helps bring the body back into homeostasis. (Lack of homeostasis is the cause for most common-day-illnesses). The isolation tank is one of the most productive, non invasive stress management techniques available.
*Cortisol- steroid hormone secreted by adrenal gland

ii. “The Anti-Gravity Explanation” is that 90% of all central nervous system activity is occupied by gravity. By freeing our brain and skeletal system of this ‘pulling’ of gravity in the tank, we can liberate most health problems like bad backs, sagging abdomens, aching feet, and joint/muscle tension.

iii. “The Brain Wave Explanation” was developed during a study of Zen monks, and their brain waves while in a deep meditative state. During this time, there was an abundant production of theta waves*, which are also produced during floatation meditation. These waves are continuously produced up to three weeks after tank usage, and show tremendous advantages in day-to-day life.
*Theta waves- relaxing, creativity promoting waves that allow vivid imagery while still conscious of surroundings.

iv. “The Left/Right Brain Explanation” is the balance between two very opposite, yet vital functions. The left hemisphere of the brain excels at details, processing small scale information, and operating analytically. The right, however, works with large scale information and pattern recognition-visually, this side is often drowned out by the constant chattering of the other side. During the absence of external stimuli, the mind enters a state where the entire universe spreads out before your eyes, exercising that side that is so often neglected.

v. “The Biofeedback Explanation” is the natural communication between your mind and body. When the floater is in a state of tranquility, he/she is able to deeply focus on any part or system of the body. Overall this gives us a better understanding of how our body’s function which helps us direct our healing energy to problem areas.


6. Concerns

a. Will I float? I don’t normally float in water.

Yes. It is impossible NOT to float in the tank. One thousand pounds of Epsom salts dissolved in water make a buoyant solution so much denser than water alone. So no matter your weight or height you will float on your back like a cork. As you lay back the water will reach the temples leaving your eyes, nose, and mouth fully exposed.

b. Can people drown in the tank?

No. Not unless they lay face down in the water and can tolerate the sting of the Epsom salt on the eyes, nose, and mouth.

c. What effect does the Epsom salt water have on my body?

According to the research of Dr. John C. Lilly, using a saturated solution of Epsom salt (MgSO4+7H2O-1.3 grams per cubic centimeter), allows the whole body to float near the surface of the water. This salt solution eliminates the effects of gravity on the body and allows the floater to attain the deepest state of rest possible.

Another benefit of floating in Epsom salt water is the absorption of important minerals. Epsom salt helps address key mineral deficiencies like magnesium. Magnesium is the second most abundant element in human cells. A lack of this key mineral attributes to America’s high rates of heart disease, stroke, osteoporosis, joint pain, digestive ailments, chronic fatigue, and stress-related disorders. And due to our modern changes in agriculture, as well as processed diets, magnesium depletion is further compounded.

It may seem that magnesium supplements may be a more convenient way to create sufficiency. However, studies show that not all forms of supplemental magnesium get absorbed well through the digestive tract. Epsom salt, which is rich in both magnesium and sulfate, is easily absorbed through the skin. What’s more, the sulfate molecules play an integral role in the formation of brain tissue, joint proteins, synovial fluid, and aid in the cellular detoxification process. Aside from the positive effects of sensory deprivation, floating in Epsom salt has been shown to provide the following benefits:

  • Improves heart and overall circulatory health
  • Improves cellular oxygen utilization
  • Reduces frequency of migraines
  • Reduces inflammation and relieves muscle cramps
  • Gives the skin and hair a renewed glow
  • Helps maintain proper calcium balance and regulates electrolytes
  • Helps regulate insulin
  • Relieves stress and creates feelings of well being
  • Flushes toxins and heavy metals from the cells

d. Is it dangerous to sleep in the tank?

No. In fact many people safely fall asleep in the tank as a result of being so relaxed. Even those who say they never sleep on their backs in bed, do so very easily in the tank. People may think it is unsafe due to the fear of rolling over. But because of the solutions density, it is very difficult to turn over. If this were ever to happen the salinity of the water would irritate the eyes and nose- immediately waking the floater.

e. Can two people float in the tank at the same time?

Floating is intended to be a private, individual experience.

f. What is used to keep it clean?

It’s important to know that the isolation tank is already a sterile environment due to the high concentration of Epsom salt. Just as no microorganisms can live in the Dead Sea the same goes for the level of salinity in that of an isolation tank. However, float spas normally use a surface skimmer, cartridge filter, ozone filtration system, and/or disinfection process (such as ultraviolet sterilizations and hydrogen peroxide) to keep the tank microbe and sediment free. Being that health codes vary around the world, some float centers need to use small amounts of swimming pool chemicals, like chlorine and bromine, to be health code compliant. The filters are turned off during the session to keep the space as quiet as possible. Note that the floater is asked to shower and rinse thoroughly before and after the session as well.

g. What if you have claustrophobia or a fear of being alone in the dark?

The thought of being in a dark, confined space can be frightening to some. However, most recent chamber models are big enough to stand and walk around in. Remember, you are in complete control of your surroundings. In some tanks, the light switch is arms length away. Also, there is no lock on the chamber door. If you are one who has a fear of the dark, try exposing yourself to the dark environment in small increments. If need be, you can exit the float tank at anytime.

h. Is the tank air tight?

No. Air enters through a circulation vent which keeps oxygen circulating. Some updated models have a pure oxygen feed to the tank chamber.

i. Will I have Epsom salt water stuck in my ears?

No. It is recommended to wear ear plugs just in case. Most float spas provide ear plugs to enhance the floating experience.

j. Is the salt dangerous to your eyes?

No, but it can be a little uncomfortable. So keep your hair pushed back and keep your hands away from your eyes to avoid it. A spray bottle filled with spring water is typically provided for instant relief.


[1] Wikipedia contributors, “Isolation Tank” Wikipedia, The Free Encyclopedia, http://en.wikipedia.org/wiki/Isolation_tank (accessed November 29, 2011).