FAQs about Scuba Regulators

What Does Alternate Air Source Mean?

Simply put, an alternate air source (usually called an 'octopus') is an extra hose and mouthpiece. Carrying an alternative breathing gas source is part of a standard diving regulator setup.

Having a second stage regulator means a second person (e.g. a dive buddy) can use it to breathe air from the supply stored inside the same scuba cylinder.

For instance, two divers can share the same air supply in a situation where one of their second stages has failed, and use it to make a safe ascent to the surface.

How Do First and Second Stage Regulators Differ?

There are several major differences between the 1st and 2nd stages on scuba regulators. Here is a simple explanation of the main ones:

• The regulator first stage is the component that connects to the valve assembly on the top of a scuba cylinder.
• It reduces (lowers) the pressure of air stored inside the gas tank (typically 200 bar or 2900 psi) to an intermediate pressure held inside the hoses. The two (2) low pressure hoses connect to two separate second stages (the primary and the alternate air source).
• Scuba divers hold the rubber or plastic mouthpiece attached to the second stage (the demand valve) in their mouth when breathing underwater.
• The most important part is for the 2nd stage to reduce the intermediate air pressure (held inside the hose) to an 'ambient' pressure. In simple terms, the ambient pressure should match the depth of sea water that surrounds the tank.

Note: Another section highlights the key differences between balanced regulator vs. unbalanced regulator, and which system is better for new divers.

What is a Yoke Connector in Scuba Diving?

You've probably heard about it, but what exactly is the yoke (often called the international fitting or the A clamp)?

This is one of the easy scuba regulator FAQs to answer. The yoke simply connects the first stage assembly to the cylinder valve of the tank.

Made from metal, the 'oval' shape yoke fitting is a simple harness that sits over the tank valve to keep the regulator in the correct position. The connection must be correct to allow air to pass into the low pressure hoses.

How Can I Stop Scuba Diving Jaw Pain?

There are several ways to tackle the question we get asked about the best ways to stop scuba diving jaw fatigue. Despite being a common problem, the issue can be quite painful for learner divers.

Check the Regulator Mouthpiece

As much as anything, gripping or biting the mouthpiece too tightly with your teeth is likely to exacerbate jaw pain after diving (e.g. temporomandibular joint syndrome).

You can get different mouthpiece designs, but try to avoid the stiff rubber versions. Instead, find one that feels comfortable between your teeth (without having to bite down too hard).

Despite being less robust, and a little more expensive, silicone mouthpieces are generally a lot more pliable and cause less jaw fatigue. Most divers (myself included) find soft silicone mouthpieces more hygienic and easier to use.

Pro Tip: Adding swivels and elbow joints at the point where the low pressure hose connects to the mouth piece may help.

Check the Low Pressure Hose Connection

It's not uncommon with some scuba setups for the 2nd stage low pressure hose to tug the mouthpiece to one side (especially when turning your head).

As a result, you may be using a tight grip to keep the gum shield in place - causing your jaw fatigue. Using a swivel joint hose adaptor may help to alleviate this problem.

This has a ball joint style design that allows the hose to rotate easily which stops it from pulling as you turn your head.

Having the ball joint design means the hose can rotate easier. Furthermore, swivel joints can also improve the positioning when sharing air with a buddy.

Thus, you can turn the mouthpiece to face the diver who is receiving your air supply, without having to pull or twist the hose.

Is the Dust Cap a Necessary Part for My Regulator?

During the PADI® Junior Open Water Diver course, one of the youngsters asked us whether they need to replace the regulator dust cap if it gets lost.

As a matter of fact, dust caps are important pieces of kit. Taking steps to ensure no water enters the first stage component is one of the basic skills beginners need to learn.

A simple, inexpensive, rubber dust cap creates a seal so that water does not go inside the opening on the first stage (e.g. when cleaning and servicing scuba regulators).

How to Stop My Scuba Regulator Hitting My Head?

We have several answers to the question of "how can divers prevent the regulator 1st stage from banging the back of the head". We know from personal experience, it happens most often when looking up towards the surface.

In fairness, the problem is only common for divers who dive with a single cylinder strapped to their back. Hence, the chunk of metal at the top of the tank (valve assembly) sits in line with the rear of the head.

Here's the bottom line:

Of course, all divers should have a basic understanding of how to assemble a scuba kit. But, aluminium and steel tanks are different in shape, thickness, and length.

1. Inverting the 1st Stage

In some cases, you will be able to invert the first stage (set it upside down). Even though most 1st stages are set up with the bulky section pointing upwards, you may be able to lose an inch of metal by inverting the assembly.

It's important to understand that this quick fix doesn't work with all designs. But, if yours is more bulky on the top than the bottom, try unscrewing the hoses and swapping them to the other side.

2. Lowering the Cylinder Height

One of the common mistakes that new divers make is adjusting the BCD too low on the tank (e.g. mounting the cylinder too high).

If so, move the tank band a little further up and closer to the top of the cylinder. But, having the tank too low will feel cumbersome and you'll have some buoyancy problems too.

Most scuba instructors recommend having the top part of the buoyancy control device level with the neck of the cylinder. Thus, the 1st stage will sit close to the crook of your neck.

3. Looking Up with Your Shoulders

One of the things you learn in the PADI Dry Suit Certification is to look with your shoulders. Drysuit divers know that you're likely to lose the watertight neck seal if you turn your head or look up.

So, try looking sideways with a gentle turn of your shoulders and don't lift your chin if you're going to look up to the surface.

4. Adjusting the Harness

Do you dive with a backplate and wing BCD setup? Is the 1st stage hitting the back of your head? If so, the harness may need some adjustment or you may need a different backplate for your stature.

Another solution you can try is adjusting the shoulder straps so the whole assembly sits slightly lower down on your back.

Note: As a last resort, wearing diving hoods can add some cushioning and help protect the occipital bone. It won't completely stop the regulator from hitting the back of your head. But it will keep you warm and it should be a little less painful.