It depends on a few crucial factors.  Which makes it entirely inaccurate to answer how long does a scuba tank last with a definite answer like 20 or 30 minutes.  Nonetheless, scuba pros will tell you that an 80-cubic-foot standard aluminum tank will last about 45-60 minutes before hitting reserve, on a 40-foot dive.

With those figures, you can estimate how long an oxygen tank will last on a 130 feet dive.

But before that estimate, here are the five vital factors that will affect the final figure:

1. Tank Volume

Source: How Long Will My Tank Last

Scuba tanks come in a variety of sizes.  The aluminum 80-cubic-foot mentioned earlier is the most common of them all.  It contains air, 80-cubic feet, compressed to 3000 PSI (pounds-per-square-inch).

For deep diving, it’s best to use such big tanks.  The higher the internal volume, the more prolonged the cylinder will last underwater.  However, the best scuba cylinder is the 12-liter one.

Remember, there are two kinds of scuba tanks: aluminum and steel.  The type of container you own plus how well it’s maintained can also affect its oxygen holding capacity.  The DOT (US Department of Transportation) regulates all scuba tanks, and each cylinder should undergo hydrostatic testing every five years.

2. Tank Pressure

Source: Why Choose Low Pressure vs High Pressure Scuba Tanks

Most diving cylinders get filled at 200 bar (3000 psi).  There are others filled at 300 bar (4000 psi) or even more, but they’re rare.  Always check a tank’s maximum working pressure because it determines how much oxygen it holds.

So how long does a scuba tank last in terms of pressure? You guessed it- The higher the psi, the more extended the dive.

3. Depth

Source: How long does a scuba tank last?

While scuba diving, the deeper you descend, the more pressure around you increases.  The pressure increase doesn’t affect the air inside your tank.  Because the air gets compressed at high pressure and the container is quite rigid.

However, water pressure compresses air exiting the tank and flowing your regulator horses, plus second stages.  For example, it takes twice the amount of air required to fill one cubic foot of space (at the surface) to fill the same space at a water depth of 33 feet due to compression.  That means that you will consume twice the amount of air at 33 feet compared to your intake at the surface.

Therefore, you can’t answer how long does a scuba tank last without considering that you will take in a lot of air at 130 feet.

4. Lung Capacity

Many things that differ from person to person. And one of them is lung capacity.  Usually, bigger people have more lung capacity than small-size individuals.  Meaning that if two different sized divers with the same breathing rate scuba dive, the smaller one will require less amount of oxygen to last as long as the bigger one.

Why?

Because the bigger person needs more air to fill his/ her lungs than the small guy. Still, lung capacity doesn’t have to matter if you improve your breathing rate to control air consumption.  Thus, you can accurately judge a person’s lung capacity by size alone.

5. Breathing Rate

Source: Breathing Tips For Scuba Divers

While underwater, the more breaths you take (per minute), the faster your tank depletes.  If you want your cylinder to last longer, you ought to breathe slower.  And how do you do that?

Clear your dead-air space off carbon dioxide by exhaling longer.  Contrary to popular belief.  This carbon dioxide is what triggers the urge to breathe and not lacking oxygen.

Your body triggers the urge to breathe if the level of carbon dioxide in your lungs is high enough.

Nonetheless, other factors that affect your air consumption rate whether you exhale enough or not.  They include buoyancy control, experience level, stress, and amount of exertion needed when diving. All in all, relaxed, deep and slow breathing will reduce your air consumption.

How long does a scuba tank last at 130 feet?

Source: Scuba Diving for Beginners – Understanding Atmospheres Underwater is Easy

The simple answer is generally less than one hour.

Since an average scuba diving beginner, in calm water (80° degrees Fahrenheit), breathing normally, would take about an hour to empty an 80 cubic foot cylinder at 33 feet.  It’s easy to double this time if you train yourself on the economy of motion, plus breathing/ buoyancy control.

Scuba diving in a cave is much different from open water and cavern diving.  While you have access to natural light with these types of diving, caves can get pretty dark.  This is why you need the right equipment and experience to successfully explore caves as a diver.  Even though most people dive for recreational purposes, cave diving is more technical.  It is popularly done for research expeditions, although some people view it as a sport.

In fact, if you are a recreational diver who has no experience in cave diving whatsoever, you shouldn’t assume that diving in a cave will just be as smooth as open water diving.  Moreover, whereas you might be quite familiar with the safety protocol employed in your typical diving endeavors, cave diving is a whole different ball game.  If you don’t invest your time in learning how to do it right, the chances are that you may be handing yourself a death sentence.

On the other hand, scuba diving in a cave is an experience like no other.  Some divers have described it as the closest feeling they will ever get to being in outer space.  Deep underwater caves have a lot to offer.  You get to see rare sea plantations and creatures that many people will never see. This why cave diving is appealing.

If you intend to dive in a cave at any stage of your life, you should know that as much as it is interesting and thrilling, it is also extremely risky.

So, why is it dangerous to scuba dive in a cave?

It is a form of penetration diving

Source: Diving St Johns Caves – deep penetration to caves

In most diving emergencies you can at least swim vertically as you try to find safety.  But what if there is a cave ceiling preventing you from doing so? Swimming vertically is no longer a viable option.  You need to find an opening that leads out of the cave.  This is quite challenging, especially when you are panicked and can barely think straight.

There are myriad challenges that arise when you are submerged underwater and in grave danger.  First of all, the exit of the cave may be quite a distance from where you are held up.  Secondly, your oxygen tank may run out, depending on how much time has elapsed since you got into the water.

Visibility

Source: SCUBA Diver’s Flutter Kicks Silt Out Cavern at Blue Grotto in Florida

While you may enjoy good visibility with both open water diving and cavern diving, caves get quite dark and creepy.  The visibility in underwater caves varies between low to non-existent.  In addition, you may experience some good degree of natural light in some parts of the cave whereas you have to contend with utter darkness in some.  Imagine being thousands of feet under and you have to navigate without a glimmer of natural light at times.

In such circumstances, artificial lighting is essential.  If anything was to happen to the lighting, you would be in grim danger.  Moreover, there are other elements in underwater caves that can interfere with your visibility even when you have the right gear and lighting equipment.  Some of these elements include sand, silt, mud and other forms of sediment.  These can jeopardize visibility, especially when you really need it to navigate a treacherous area.

When silt is accidentally stirred up, you are likely to be in a precarious situation as a diver.  Open water diving gives you a lot of options to evade the silt and proceed.  However, these options are limited in a cave, making it more dangerous.

Water Currents

Source: Cave diving strong current

It is normal to encounter currents in large water bodies.  This is a necessary evil for anyone who surfs, swims or scuba dives.  It is also something that most people underestimate.  Nevertheless, water currents are a force of nature to be reckoned with.  From a physical perspective, water currents are eminently demanding.  If you ever have to contend with these forces, rest assured you will feel completely helpless.

What makes it worse for a diver is that it’s difficult to estimate both the speed and the impact of the current.  In addition, currents are known to accelerate the rate at which you use air while in water.  If you are caught by a strong current while exploring an underwater cave, you will be cornered.  The current works against any effort you put towards saving yourself, leaving you with no choice but to succumb.

Facing the wrath of water currents is one of the most unpleasant experiences you can ever come across when scuba diving in a cave.  A current that is about 1 knot can result in a flooded mask, taking away your visibility.  If it’s stronger than that, you can be swept away and driven to wherever it leads you.  Let’s say you survive that, you will need to regain your desired position.  If you are stranded and have to find your way, time will be ticking and your air will diminish drastically.  This can, in turn, reduce your chances of ever finding safety alive.

Getting lost

Source: Lost In An Underwater Cave, Dont Let This Be You

This is another somewhat overlooked danger of scuba diving in a cave.  Nevertheless, it is a real danger.  Getting lost anywhere is a thrilling adventure, especially if you can easily ask for help and find your back.  People get lost all the time while exploring new countries, towns, cities and so on.  However, if you get lost while in a cave underwater, it wouldn’t even equate to your worst nightmare.

Instead, you would be struggling to find your way out with limited resources in terms of air.  More so, you are likely to panic.

Getting trapped

Scuba diving in a cave is also regarded as a dangerous adventure as it’s easy to accidentally get trapped between rocks.  This occurs mostly when you tread on unfamiliar grounds.  No matter how experienced a diver is, unfortunate things happen due to the complexity of underwater caves.  There is always that possibility of swimming through the opening of a cave and never coming back.

Air Supply

The air supply is a delicate aspect of cave diving.  Different people use varying levels of air.  You also don’t want to go into a cave too heavy.  Since this is an intense activity, especially when navigating complex caves, you can be under immense stress.  It is therefore difficult predicting just how much air you will need and in case you get that wrong, there is the danger of drowning hovering over your shoulder.

The other air supply element that comes into play is the mixture of gases.  The partial pressure of a gas is a factor that affects various types of scuba diving, and cave diving is no exception.  Excess oxygen, as well as nitrogen, makes the situation even more sensitive for divers.  If you add other underlying factors such as extremely cold water and the nature of your movement, which may drain your energy physically, the risk becomes even greater.

Difficult Rescue

Normally, there are safety protocols that are used in scuba diving.  Although there are communication methods used to communicate emergencies by scuba divers, the rescue process itself can be complicated.  For example, it may prove difficult to find someone who has been trapped in a cave and probably lost lighting as well as communication.

In addition, there are not many well-trained rescuers for saving scuba divers who find themselves in precarious situations when scuba diving in caves.  In some cases, experts have to be flown across states and countries for a rescue mission.  This could take hours and the rescue mission itself could stretch to several days.

If you compare this to ordinary scenarios which involve simple rescue procedures in swimming, scuba diving in caves easily occupies a top spot as the most dangerous sport.

Cave diving and safety

Source: Extreme Cave Divers : Documentary on Cave Diving and Lost Underwater Worlds (Full Documentary)

Regardless of the dangers associated with scuba diving in caves, nothing has ever deterred the curiosity of men to explore the universe.  This is why treasures have been discovered in some of the most dangerous places in the world.  Additionally, research is an important aspect of cave diving.  This is however not the only reasons why people turn into scuba diving enthusiasts.

There you go- the above answers the question- “why is it dangerous to scuba dive in a cave?”  But since it is a fun activity with lots to offer, enthusiasts can scuba dive into the most dangerous caves just for the fun of it.  In short, people are not about to cease doing it.  This is why there are extensive safety measures put in place for diving in caves.

It is said that most cave diving fatalities are as a result of not complying with all the set-out safety measures coupled with a lack of proper training and experience.  While there are not enough statistics to ascertain this, any cave diver would understand the risk involved.

Despite the numerous safety measures for cave diving, divers should stay within their own limits.  This means that one should dive as far as their training allows.  If you follow these great rules, you probably will never have to fight for your dear life deep in an underwater cave.

The beauty in cave diving is out of this world.  Those who have done it successfully are always craving for more.  The only way to experience it is to actually do it.  Now that you know of all the possible dangers, you can make an informed decision of whether to do it or not.

Source: How to Equalize Ear Pressure using the Valsalva Maneuver while SCUBA diving

If you like diving, then you know that divers mostly experience injuries to do with the ear.  Even though people tend to rank decompression illness as the most common diving injury, those who have gone deep below the water long enough know that the most common injuries have to do with the ear.  Every diver experiences these kinds of injuries at one point or another.

The condition is also referred to as ‘ear squeeze’ by some divers.  Diving injuries to the ear have to do with the air pressure in the tympanic cavity, at the middle section of the ear.  If you are here because you keep asking the question”how do I stop my ears from hurting when I Scuba dive” then this is the article for you.  We shall be focusing on ear injuries to do with pressure imbalance, the type know as barotrauma.

How barotrauma occurs

Pressure injuries of the ear are caused by an accumulation of blood and other fluids in the middle of the ear.  It could also cause a ruptured eardrum due failure to equalize pressure around the middle section of the ear during diving or flying.

The mechanism

Source: What Happens Inside Your Ear During A Scuba Dive?! | Equalizing Ears Scuba diving

The tympanic cavity should always maintain a pressure balance with its outside surroundings.  You can equalize this pressure when needed through the Eustachian tube, whose function is to provide an air passage to the throat from the middle ear.  That is how you are able to balance this pressure by swallowing when you feel some discomfort.

If the Eustachian tube is obstructed, then equalization can be a problem especially during times when there is a quick pressure change like when on a quick descent.  The pressure imbalance that occurs creates a vacuum in the middle of the ear that causes the eardrum and the tissues around to swell.  Fluid then leaks from the ear and bleeding occurs from ruptured vessels.  As this worsens, your active attempt to bring the air pressure back to normal.  A Valsalva maneuver is ill advised in this case as it can damage the ear further.

How it manifests

Source: Listen to Your Ears – Physics and Pressure Effects

When a diver cannot equalize the pressure in the middle of the ear during descent, they will first fell some discomfort.  As the descent continues the discomfort, which feels like clogging in the ears becomes painful.  Going any lower just worsens the pain and causes such pressure imbalance in the ear that the diver begins to bleed from the ear due to fluid build-up.  As the condition worsens due to further descent the eardrum is likely to rupture which relieves the pain.  A ruptured eardrum can cause hearing loss, vertigo and other infections due to exposure.

How barotrauma is diagnosed

Even though there are plenty of articles on the internet with a lot of valuable information, there is nothing like a doctor’s opinion when it comes to such injuries.  Rather than wait longer and make it worse you are better of seeking the attention of a doctor whenever you feel the need to after a dive.

There are a series of questions used to identify what problems a diver is experiencing. These are meant not only to find out about ear squeeze but other injuries to the ears as well.

Some of the questions include:

• Whether the diver experienced any difficulty balancing air pressure during the dive.

• When exactly the symptoms were felt, whether during the dive or upon reaching the surface.

• Whether symptoms developed during descent or ascent.

• History of ear or sinus infection.

• How long the symptoms lasted.

After examination the doctor may detect a perforated eardrum, swelling and inflammation of the eardrum or you could be totally fine.  Such injuries may also cause facial paralysis.  Examining them does not need any blood work or X-rays.

How to manage barotrauma

Source: Ears 101 : How to Relieve Ear Pressure Pain

When diving

The first and most obvious thing to do the moment you start experiencing the pain is to stop going lower and try to equalize ear pressure.  You may need to ascend a number of feet to make equalization easier.  If you are still not able to equalize ear pressure you are better of stopping the dive completely and staying safe.

First Aid

If you feel this bulging in the ears it is best to stop diving altogether for a while.  You should also get a nasal decongestant-these can be found as drops or sprays.  Applying the decongestant will bring down swelling of the Eustachian tube and nasal mucosa enabling the Eustachian tube to open thus draining fluid from the middle of the ear.  You should not, for any reason, put drops in the ear.

Medical care

A physician’s evaluation is paramount for those who experiences fluid discharge or bleeding from the ear canal.  This is also advised for divers who have experienced pain and fullness in the ear for longer than a few hours.  Dizziness and vertigo are signs that the diver needs immediate evaluation by a medical practitioner.  The diver may also need emergency services when vertigo and dizziness worsen.

Ways to avoid barotrauma

For the divers stilling asking the question “how to stop my ears from hurting when I Scuba dive” you should also note that there are times when you just can dive at all.  You are advised to stay away from diving if you have a cold or congestion.  It is also advisable to descend as slowly as you can.  If you still feel the discomfort after several trials, you should call off the dive as you could sustain injury that will keep you from diving for the better part of the week.

Injuries of this kind should always be handled with the seriousness they deserve.  Treating them lightly worsens the injuries sustained and can even cause permanent hearing loss.  Divers, like any other sport enthusiasts, are advised to follow physician rules at every step for their own wellbeing.  If a diver chooses to ignore instructions from their physician they can pay dearly for it.  Taking the right precautions keeps you healthy and safe for the next dive.

PLEASE NOTE THAT THIS ARTICLE IS NOT INTENDED TO PROVIDE MEDICAL ADVICE BUT IS INFORMATION ONLY.  IF YOU EXPERIENCE ANY MEDICAL ISSUES WHILE DIVING CONSULT A MEDICAL PROFESSIONAL IMMEDIATLY.

https://www.youtube.com/watch?v=7kaZRFrbvWM

A common question asked by many novice scuba divers is “how deep can you scuba dive?”.  Unfortunately, the answer isn’t as straightforward as drawing a line on the sand (or water, in this case) and saying, here is how deep you can scuba dive.  You’ll have to consider many factors, including the breathing gases, the diver’s experience, and especially a diver’s personal tolerance to high pressures.  We’ll look deeper into these factors and see for ourselves the maximum safe depth anyone can scuba dive, as well as try to understand why these precautions are around in the first place.

Source: How Deep Can we Dive | 2016

Source: Is Scuba Diving Safe?

How Deep Can You Scuba Dive?

The deepest anyone has ever been whilst scuba diving is 1,044 feet, a record set by Ahmed Gabr on September 18, 2014.  Now, just because experienced technical divers have regularly gone into depths as deep as 1,000 feet and beyond, doesn’t mean anyone else who has a recreational diving background can do it.  Diving this deep is a feat not everyone can do, and requires a lot of preparation, both physically and mentally to pull off. F or anyone who’s not experienced, or has very little in the way of training, they’ll have to settle for a depth set by many scuba diving organizations, which is 130 feet.

So, the short answer to “how deep can you scuba dive?” is 130 feet.  But why 130 feet?  Well, there are many reasons, and we’ll talk about all of them today.  Once we’re done, you should be able to understand why it’s foolish to even consider breaking beyond this depth limit, and why going as deep as 1,000 feet is a remarkable achievement for any technical diver.

Concept of Decompression

One of the biggest factors as to how deep can you scuba dive is the concept of decompression.  By its most basic definitions, decompression is the release from compression, or pressure.  Whenever you go underwater, you’re entering an environment that has a much higher pressure than what you experience on land.  The deeper you go, the higher the pressure that’s bearing down on your body.  Water itself is about 750 times denser than air on land and being in this sort of environment causes your body to undergo certain changes; changes that can be harmful.

Source: Decompression Sickness

To compensate for these changes, a diver can ascend from their dive, which lowers the pressure on your body, which then allows you to mitigate these changes accordingly.  Unfortunately, rising too quickly means your body wouldn’t be able to regulate fast enough, causing even more problems.  That’s why divers undergo what they call “decompression stops” on their way up from an extended deep dive to allow their body time to adjust as they go.  While undergoing a decompression stop, you’ll have to take into account your air supply, which adds another dimension to the concept of decompression.  You’ll have to remember that while you’re no longer moving in terms of depth, you’re still using up air.

So, to summarize, staying too long in deep water is bad, but going up too quickly is also very bad.

Nitrogen in your Bloodstream

Ear pain is a common complaint among scuba divers and some call it the ear squeeze.  As a diver, when going deeper under the water, the pressure from the outer environment will increase and as a result, your middle ear, that part behind your eardrum, will get squeezed by the increasing pressure that the water from outside puts on you.  The middle part of the ear is usually made of the eardrum (tympanic membrane) and bone and the space between the two is air-filled.

There is a tunnel, known as the Eustachian tube, which connects this part of the ear to the backside of the nose.  Any outside air that goes through the tube equalizes the pressure between the middle ear and the outside world.  Ear squeeze or pain will arise when the Eustachian tube malfunctions and a pressure difference arises.

Source: What Happens Inside Your Ear During A Scuba Dive?! | Equalizing Ears Scuba diving

Scuba diving ear pain

Ear can pain occur while decending during scuba diving, after the diver drops deep under water.  The squeezing ear pain occurs near the ear surface where relative pressure changes are greater. Every foot below the water surface will increase the pressure on the ears.  On average, for every 33 feet under the water, the atmospheric pressure will increase by around 1 atmosphere, which is comparable to 1-atmosphere pressure for every person standing at the sea level.

Normally, the Eustachian tube opens and allows the pressure behind the diver’s eardrum to equalize with the pressure of the seawater inside the ear canal.  However, if the Eustachian tube fails to do that, the water will push the eardrum inwards with every increase of pressure of the seawater inside the ear canal.

The pressure stretches and inflames the eardrum and causes pain.  If the diver ignores the pain and decides to drop deeper, the pressure increases further and can cause bursting of the eardrum. That will allow the cold seawater to enter the middle ear.  The result is vomiting, nausea, confusion and dizziness.

Rapid descents and ascents in commercial air flight or while driving a car might also cause equalization problems of pressure inside the ear, but not similar to that expected in diving.  The problem is likely to cause an ear pop but it is unlikely to cause an ear squeeze.

The types of problems

Almost each of the most common ear problems associated with diving will fall in one of the three categories.  The problems can either affect the outer ear, the ear canal and the tympanic membrane (anything to the eardrum).

The second category of the pain is associated with the inner ear and it includes anything on the diver’s eardrum such as the middle ear, the oval window and round window.

The third category of scuba diver ear related problems related to the Eustachian tube and the sinuses.  The purpose of the Eustachian tube is to supply air to the inner ear and to facilitate equalization of the body.  If a problem occurs in the area, the equalization might become difficult.

The outer ear problems

The diver’s outer ear might suffer two primary issues, wax build up and infections, both result in severe pain when diving in addition to difficulty equalizing.   Because wax build-up makes a plug in the ear it makes it hard to equalize properly.  The best cure is to irrigate the ears with some warm water.  You can buy home kits to treat the problem or seek professional medical help.

Source: Ears 101 : How to Relieve Ear Pressure Pain

Various infections affect the outer ear but most of them are treatable with simple eardrops, which treat infections and reduce inflammation.  To identify the best eardrops for your problem, you will need the help of a medical professional.  If you are more prone to the outer ear infections, you will have to rinse the outer ear regularly with some clean water after each dive.

The inner ear problems

The inner ear problems exist in two different types, barotraumas and infections.  Infections result from various things and to solve them in a better way, you will need to consult a doctor and potentially take some medication.

Source: Listen to Your Ears – Physics and Pressure Effects

Barotraumas are another form of inner ear injuries that result from pressure.  They primarily occur if the diver is not careful when descending or equalizes very hard or fails to equalize sufficiently. To avoid them, you will have to ensure that your ears and sinuses are in the right shape and unblocked and to equalize gently and regularly when diving.

The sinuses and Eustachian tubes

The Eustachian tubes are the most important when it comes to proper equalization.  The most common problems that affect them are inflammation and congestion.  To avoid the problems associated with congested or inflamed Eustachian tubes, you will have to ensure that you are healthy before you start diving.  Do not try to dive when you are partially congested or after a cold because the mucus build-up is likely to interfere with your proper equalization and will cause more problems as you force the body to do something hard.  Use sprays or decongestants to clear up your tubes before you go diving, under the advice of a medical professional.

Source: Ears and Sinuses: Barotrauma for the Dive Professional

The Eustachian tubes are usually guilty in case of reverse blocks that affect the sinuses or ears.  Reverse blocks are very similar to squeezes but they occur on ascent.  As the diver goes up and the outside pressure starts reducing, the air in the sinuses and the ears starts escaping automatically and the inside pressure starts to equalize with the outside water pressure.  However, mucus might block the sinuses and the Eustachian tube, therefore, making it hard for the air to escape.  This can result in pain associated with pressure imbalance.  The best solution is to re-descend until the sharp pain has ended.  After that, recommence the ascent as slow as possible so that the air trapped inside can escape.

Conclusion

Mostly, ear pain associated with scuba diving goes away by itself, within one week, and without any long term effects.  If the eardrum ruptures, it will heal itself in a longer period, seek medical adivce but a surgical repair might be necessary.  If facial paralysis is present seek medical advice and it may be temporary.  In the case of mild hearing loss seek medical advice.

This article is not intended to offer medical advice, but to only provide information.  If there is any questions regarding any hearing issues seek the advice of a medical professional.