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!
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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.
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 is 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.
Is It Alright To Have Air Inside Your Scuba Tank when Not in use?
Yes, it’s okay to store residual air in your scuba cylinder as long as the pressure inside the tank does not exceed 200 psi to prevent moisture from forming.
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.
How To Maintain the Right Pressure when Storing A Dive 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 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?
Leaving your tank full can cause several issues, including structural damage to the tank valve. When tanks are full, the constant high pressure of compressed air inside the tank can cause damage to the valve 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 direct sunlight.
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.
Can Air Go Stale in a Scuba Tank?
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 rust, 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.
Symptoms of Bad Air in a Scuba Tank
Breathing bad air from a scuba tank is downright detrimental and the sooner you identify the symptoms the better:
The Air Has an Unusual Smell or Taste
Strange or foul smells coming from the tank when you open the valve. Good air should have little to no odor. A smell like rotten eggs or chemicals could mean contaminants in the tank.
Breathing And Nauseating Issues
Shortness of breath or that your air supply seems to run out much faster than expected. Contaminants take up space, leaving less breathable air in the tank.
Dizziness, nausea, vision changes, confusion, headache, or loss of coordination during or soon after a dive. Bad air could contain carbon monoxide, and carbon dioxide, which can cause these symptoms.
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.
Greasy Valve Neck
An oily residue around the tank valve. This can occur with hydrocarbon contamination.
Build up on First-Stage
If your regulator shows signs of rust particle buildup on the first-stage filter, that might mean the interior of your tank has rusted and rust flakes are contaminating the air.
6 Must-Follow Tips for Storing Your Scuba Tanks When Not In Use
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:
- 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.
- 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.
- Remove the regulator: When not in use, remove the first stage 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.
- Protect the valve: The valve on your scuba tank is a critical component, so protect it by all means. Use a valve cap on the tank and a static bag to store the valve to keep out dust and debris, and store the tank in an upright position to prevent damage to the valve or other components.
- Get it inspected: Before using your tank after a long time get it VIS and Hydro tested properly.
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.
