Alternate Air Sources

Diving became a lot safer with the introduction of alternate air sources. These devices allow you to share air with your buddy in the event of an out-of-air emergency. The three common alternate air sources are octopus regulators, integrated air sources, and redundant scuba systems.

No matter which option you use, it’s important to place it at or near your chest so your buddy can easily locate and retrieve it when needed. Clips are available that hold the air source’s mouthpiece secure, but allow your buddy to quickly pull it free when needed.



An octopus is an additional 2nd stage that is connected to your 1st stage, and is the most common alternate air source used today. With an octopus, both you and your buddy can breathe from your cylinder while ascending.

The octopus works like any other 2nd stage, but most have a couple minor modifications. The most important is a longer hose that allows it to reach your buddy. Another common modification is a yellow cover to make it more visible when clipped to your chest. Some, like the lower example to the left, have a low-profile design to decrease their size.

The octopus is popular because it’s easy to use and costs less than other options. But keep in mind that when using the octopus, your air supply will be depleted faster because two divers are sharing the same air source.

octopus regulator

Octopuses are available in the standard 2nd stage design, such as the top example, or in special low profile designs, such as the bottom example.

Integrated Air Sources

Another alternate air source that’s gaining popularity is the integrated air source. This is a BCD power inflator with a fully functional 2nd stage built into it. This option is popular because there are no extra hoses or equipment to deal with.

In the event of an out-of-air emergency, the donor breathes from the integrated air source while the buddy breathes from the donor’s primary 2nd stage. This procedure is different than what most divers are familiar with, so always be sure your buddy understands this air sharing procedure before beginning the dive.

Like the octopus, integrated air sources share one air source between divers, so be sure to monitor your air supply when sharing air.

integrated air source

An integrated air source combines the features of a power inflator and alternate air source.

Pony Bottles

Redundant scuba, or a pony bottle, consists of a small cylinder with its own regulator, and is commonly referred to as a pony bottle. The cylinder may be strapped to the diver’s primary cylinder, or clipped to the BC.

These systems are heavier and more expensive than other options, but have major advantages.

With redundant scuba, you are not dependent on your buddy in the event you run out of air. It also allows you to share air with your buddy without sacrificing your own air supply. For these reasons, this system preferred for deep dives.

pony bottle

A redundant scuba system consists of a small “pony” bottle with its own regulator.

Alternate Air Source: Rules And Recommendations

Alternate Air Source: Rules And Recommendations

Torben traveled around South East Asia for scuba diving and almost didn’t come back. His affinity for gear that works and his generosity for guiding people on their own path match his energy as editor of all things travel-related

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As a diver you need the octopus. And I don’t mean that 8-legged ocean creature. I mean your alternate air source; in other words your second regulator or your backup.

The octopus works the same way your primary regulator does.

If your primary regulator fails your alternate air source is there for you. And if your diving buddy would need to share air it’s there for him too.

An alternate air source is often easy to distinguish because it is bright neon pink, orange, yellow, or green. This is usually secured within the area of your chin and the bottom of your rib cage, preferably on the right side of your body.

Let’s take a look at alternate air source rules and recommendations:

Basic Rules

Besides being brightly colored and easy to get to between your neck and ribcage there are 3 different kinds of alternative air sources. Which one you pick as a diver is totally up to you.

  • Octopus – A regulator basically the same as your primary regulator but marked with a bright color.
  • Octo-inflator – A regulator second stage attached to your low-pressure inflator. You switch over to this while your buddy gets your primary regulator in case of an emergency.
  • Pony Bottle – A 0.8-3 liter small bottle with a second stage regulator attached for breathing. This may be used by you or your dive buddy, but keep in mind it only contains a few minutes of air.

Always know your buddy’s equipment

Before you dive you need to know:

  • What air source you have
  • What source your buddy has too! You need to know each other’s alternative air sources system and how they work.

The best time to check the different systems is when you do a buddy check. Check how they work, decide what to do in case you need to use it, and make sure both of your alternative air sources completely work, without question.

Alternative Air Sources: Life Savers You Should Never Ignore

Alternative Air Sources for Diving Lifesavers

Have you ever underestimated how much air you will need while underwater? This is a common problem among both experienced and beginner divers.

Statistics show that many of the dives that result in death happened when one diver was out of air. You might encounter various problems like a gas leak in your scuba tank while diving. It’s imperative to plan and use an alternate air source.

Although you may swim with a full-sized tank, this could be tiresome. It’s for this reason why many types of technical diving need an independent alternate air source.

Nonetheless, the most recommended is the octopus regulator. The alternative air sources are only meant for an emergency.

Each diver has his or her preference depending on the situation. Some divers would rather have two alternative air sources for one dive.

Choosing an Alternative Air Source

With many options in the market, it can be daunting and overwhelming to settle on one alternative air source. It’s recommended to work with a similar brand. Using different brands can void EN testing

You also need to choose a quality product from a reputable brand. While the cheapest scuba air supply may seem like a cost-saving option, it could put your life at risk. A leaky or poor performing unit might make your breathing difficult. Go for a product that meets your budget and one that has met certain quality standards.

Alternative Air Sources

There are alternative air sources you need to check out. The main ones include Spare Air and Pony Bottles.

Spare Air

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Larry Williamson is the brain behind Spare Air. Larry designed the gadget after he ran out of the air on a deep dive. Although he’d gone with a friend, he wasn’t near. He struggled to get to the surface using the air left in his lungs but blacked out near the surface. The diving crew saved his life.

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Spare Air first hit the market in 1979. Divers use the Spare Air Model 170 which boasts of a maximum capacity of 48 liters or 1.7 cu ft. You can find a larger version with a capacity of 85 liters which also features a Nitrox version.

The one thing you’ll love about Spare Air is that it comes in smaller bottles. This means you can attach it to the BCD. You can also pass it to your buddy the larger model can give you up to 57 breaths at a surface pressure; this allows you to surface from 30 meters.

Beginner divers tend to stick to shallow depths while practicing their skills. However, new divers find Spare Air an excellent choice as it needs minimal training on how to use it.

It’s important to note that Spare Air is only meant for dives that do not need decompression. In case you end up in a difficult situation, you can apply the nozzle to your mouth and safely come up

You’ll find this bottle easy to carry on a plane as you can remove the regulator from the tank. Afterward, you can refill the bottle from a scuba cylinder, a hand pump, or personal breathing compressor.

If there’s any disadvantage here, it’s that there may not be enough air to get the diver back up and out.

Pony Bottles

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Pony bottles are more advanced compared to Spare Air. These bottles have a higher air capacity as they have a standard two-stage regulator. In fact, pony bottles act as an extension of the scuba set. They have different gauges and regulators.

In case of an emergency, all you need is to attach the bottle to the main air supply using a connector. You can then open the valve. The bottles are available in 6, 13, and 19 cubic feet. The 13 cubic feet one is the most popular and can supply enough air to allow you to make a safe ascent to the surface. This size also works best for recreational dives that do not need a decompression stop.

There are 30 and 40 cu.ft bottles if you’re an adventurous diver who enjoys deeper dives. The bigger bottles have decompression stops while the smaller ones work best when you’re looking for a safe ascent.

You can fix the pony bottle to the main scuba tank using straps or the clamps. This not only keeps them away from your workspace, but it also provides convenient access. It’s critical to understand that the pony bottle is not a stage bottle. It’s only meant for out of air cases, and should not be a part of your dive plan.

Disadvantages of the Pony Bottle:

    Can be cumbersome to carry around due to its size

Why The Location of the Alternative Air Source is Important

An alternative air source is a must-have scuba diving gear. It’s essential to attach the alternative air source in a standard position as it allows a diver who is out of the air to easily and quickly locate it.

Also, it provides extra safety in a case where your buddy is unavailable to help you out. The standard locations are on the lower chin or the corners of the ribcage. This allows you to locate the air source and use it.

When diving with a new buddy, make sure that you go through air-sharing procedures and where the emergency equipment is placed before getting into the water. This will make your scuba diving experience worthwhile.

Best Locations for Alternative Air Source Attachment

Your alternate air source should be placed in a way that your dive buddy can easily identify and secure it. Some of the acceptable places to attach your alternate air source include:

The BC Shoulder Pocket

Many BCs have a long pocket sewn into the shoulders of the chest straps. You can fold the alternate air source hose and slide the loop into the pocket. This leaves the regulator accessible and free. With your alternate source of air in your pocket, you can easily adjust the length of the hose by deciding on the best place to put the loop.

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The BC Shoulder Pocket Diving Air Source Attachment

Photo credit Wikipedia, CC by 3.0, by Pete Nawrocky

Buoyancy Compensator on the Right side

The left shoulder is a popular route through which recreational divers position their alternate air source regulator hose. Nonetheless, you can still route the tube over your right shoulder.

Chest D-ring

You’ll find integrated chest d-rings on the straps of every commercially available BC. You can use the d-rings as an attachment point for alternate air sources. There are two options for attaching your alternate air source to a chest D-ring. You can either fold the alternate air source hose and slide the loop through the ring or attach it using a quick release gadget. These attachment methods are acceptable.

BC on the Left Side

Your buoyancy compensator has attached d-rings on the left side. This allows for a quick release as you can attach your air source regulator on these rings. If you’re a left-hand user, you’ll find this position useful.

Necklace Regulator

You can attach your air source to a necklace. This means your air source hangs down the chin. In a case where you need to share air, you can give your buddy the primary regulator and use the alternate source on your neck to breath. While this is a less-known equipment setup, it could come in handy in an air-sharing scenario.

Places Where You Shouldn’t Place an Alternate Air Source

An unacceptable location is any place that doesn’t allow you to easily access an alternate air source. Some of the areas considered unacceptable include:

Inside the Lower BC pocket

Your alternate air source needs to be visible. This is the reason why they are brightly colored. The problem is that some divers may choose to tuck their air source inside the lower buoyancy compensator pocket. This location while secure is challenging to know if the diver has an extra air source.

Hanging Freely

A hanging alternate air source is dangerous in the sense that it may turn upside down. This drains the tank of air. Moreover, it may fail to function in an emergency or worse, get damaged when exposed to the environment. For example, it may get caught up on a surface. Your dive gear should be safely secured.

Which Air Source is better?

Spare Air and Pony Bottles have each their advantages and disadvantages. You can refill the Spare Air using a hand pump or at a dive shop. Pony bottles get a refill from a scuba tank.

Also, Spare Air is easy to use in an emergency. With a Pony bottle, you need to have the skills to change air supplies. Pony bottles work best when you are on a deep dive while Spare Air works well in a shallow surface.

You need to assess your dive and find out what risks you stand to face. Two alternative air sources are an excellent idea if space is not an issue.

Alternative Air Source Note

Some types of alternative air sources are meant only for rescuing other divers. You can tell the difference because the type for rescuing others has two inflators: one for you and one for the other diver. It also feeds off the same air source, which means if you are out of air, then this system will not work.

An alternative air source for self-rescue has only one, like Spare Air and pony bottles. These generally are for your use if you run out of air. However, it is possible to share them if the need arises to help out a fellow diver. These provide a second air source, which is why you can use them for self-rescue.

Make sure if you are new to diving that you understand the difference. The terminology is generally the same as they both are called alternative air sources, which can be confusing if you are not clear on exactly what you need.




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