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How Long Can You Store Air in A Scuba Tank? 6 Valuable Storage Tips

As a scuba diver, you know how crucial it is to have a reliable air supply when you’re deep underwater. One of the most essential components of your diving gear is the scuba tank, which stores the compressed air that you breathe underwater.

Not everyone in the diving community is a regular diver. Some of you probably take prolonged breaks from diving, most of them spanning a few weeks to months. Seasonal divers often have concerns about the storage of scuba tanks when they’re not diving.

One of the common questions I hear from them is: But how long can you store air in a scuba tank? In this article, I will answer this question and other related concerns. So let’s hop right in!

How Long Should You Store Air in a Scuba Tank?

Always keep in mind that scuba tanks are designed to withstand a specific pressure limit, and over time, the pressure can decrease due to natural leakage or thermal expansion. So, by no means you should leave your scuba tanks unattended for long periods of time.

The general thumb rule is: You should not store air in a scuba tank for more than three months. After that time, the air quality may be compromised, making it unsuitable for diving. The air’s quality depends on several factors, including temperature, pressure, and the quality of the air when it was compressed. To keep the air in your scuba tank in top condition, you should store it in a cool, dry place, away from direct sunlight.

Does Air Go Stale in a Scuba Tank?

The short answer is yes, it can. While compressed air doesn’t “go bad” per se, it can become contaminated with moisture or other impurities that can affect the quality of your dive. One of the main culprits of stale air in a scuba tank is moisture. When water vapor is compressed, it condenses into liquid form and can pool at the bottom of your tank. Over time, this can lead to rust or corrosion, which can affect the quality of the air you breathe.

Another issue is the buildup of other impurities, such as oil or dirt, which can collect inside the tank and affect the purity of the air.

According to DAN, the different contamination sources include impurities existing in the surrounding environment (engine exhaust, carbon dioxide, dust particles) and/or by-products of the compression process (carbon monoxide or hydrocarbons from compressor lubricants).

This can lead to symptoms such as headaches, nausea, and fatigue, which can put you and your dive buddy in danger.

Should I Keep Air in My Scuba Cylinder?

Yes, it’s okay to store air in your scuba cylinder as long as the pressure inside the tank is around 200 psi to prevent moisture from forming. But why is 200 psi the recommended pressure? The reason is that this pressure is high enough to keep moisture out, but not so high that it puts unnecessary stress on the tank or valve. You should never completely drain all air from your tank when storing it.

So, how Do You Maintain the Right Pressure when Storing Your Tank?

The easiest way is to use a pressure gauge to monitor the pressure inside the tank. If the pressure drops below 200 psi, you’ll need to add air to bring it back up to the right level. It’s important to note that you should never use compressed air from a regular air compressor to fill your dive tank – this can actually cause contamination of the air inside the tank and compromise the safety of the tank. Instead, it’s best to use a dedicated scuba tank filling system or have your tank filled by a qualified dive shop.

You should also store the tank in an upright position to prevent moisture from accumulating inside the tank walls and corroding it. It’s best to keep the scuba tank away from heat sources, such as direct sunlight or hot car trunks.

Should You Leave Scuba Tanks Full When Not Using?

Absolutely not, it’s not okay to store your scuba tank full when not in use for prolonged periods. Leaving your tank full can cause a number of issues, including potential damage to the tank itself. When tanks are full, the pressure inside the tank can actually cause the valve to become damaged, which can lead to leaks or even complete failure of the valve. This is especially true if the tank is exposed to high temperatures, such as being left in a hot car or in direct sunlight.

But damage to the tank isn’t the only concern. Leaving your scuba cylinder full can also increase the likelihood of moisture buildup inside the tank, which can lead to corrosion and rust. This is because the air inside the tank contains moisture, and when the tank is full, there’s no room for that moisture to escape. Over time, this can cause serious damage to the tank and potentially even compromise your safety while using it.

You should store your scuba tank in a cool, dry place, away from direct sunlight or heat sources. If you store your scuba tank for an extended period, make sure to check the tank’s pressure regularly to ensure it’s still within the recommended range.

What are the Symptoms of Bad Air in a Scuba Tank?

Breathing bad air from a scuba tank can cause various health risks, including respiratory problems, dizziness, headaches, nausea, and fatigue. It’s essential to be aware of the signs and symptoms of bad air in a scuba tank, such as:

Unusual Smell or Taste

if you notice a strange odor when you breathe in your regulator, or if the air tastes or smells funny, this could be a sign of contaminated air. Stop using the tank immediately and have it visually inspected by a professional.

Difficulty In Breathing

If you experience difficulty breathing, shortness of breath, coughing, or tightness in the chest while diving, it could be a sign of oxygen deprivation or carbon dioxide toxicity. Ascend to the surface slowly and seek medical attention.

Sudden changes in buoyancy

If you notice that your buoyancy suddenly changes during your dive, it could be a sign that the air in your tank is contaminated. This could be caused by changes in the density of the air due to contaminants or improper mixing.

Equipment Malfunction

If your regulator or other scuba gear malfunctions or shows signs of corrosion or damage, it could be due to bad air quality. Check your equipment thoroughly and have it serviced by a qualified technician.

6 Must-Follow Tips for Storing Your Scuba Tanks When Not Using

Proper storage of your scuba tank is essential for maintaining its longevity and ensuring safe diving. Here are some tips on how to store your tank when not in use for prolonged periods:

  1. Keep the tank in a cool, dry place: Store your scuba tank in a cool, dry place away from direct sunlight or heat sources. Exposure to high temperatures can cause the tank to expand or contract, which can damage its structural integrity.
  2. Don’t drain the tank of air completely: To prevent moisture from forming inside the tank, it’s better to store it with a small amount of air such that the pressure inside the tank remains around 200 psi. This will also help keep the tank from becoming contaminated with dust or other debris.
  3. Remove the regulator: When not in use, remove the regulator from the tank and store it separately. This will prevent any damage or wear and tear on the regulator and ensure that it’s in good working condition when you’re ready to use it again.
  4. Protect the valve: The valve on your scuba tank is a critical component, so it’s important to protect it from damage when not in use. Use a valve cap to keep out dust and debris, and store the tank in an upright position to prevent damage to the valve or other components.
  5. Get regular visual inspections: Even if you’re not using your scuba tank regularly, don’t forget to get it inspected at least once a year by a qualified technician. This will ensure that it’s still safe to use and help catch any potential issues before they become serious problems.
  6. Hydrostatic Testing: Lastly, have your scuba tank hydrostatically tested every 5 years to make sure that it can handle the high pressure of compressed air. During this test, the tank is filled with water and pressurized to a specific level to check for leaks or structural damage.


Storing air in your scuba tank for too long can affect the quality of the air you breathe. You should store your scuba tanks in a cool, dry place, away from direct sunlight and heat sources. Remember to check the tank’s pressure regularly to ensure it’s still within the recommended range.

William Dupre

William Dupre

Retired Master Diver with 20+ years of experience and 2100+ logged dives. Presently, spending my time blogging about Diving and checking off locations one by one from my bucket list of dive destinations.

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