Scuba Diving Regulator Buying Guide

A lot of scuba gear is very technical and the most technical of them all are your regulators. Well, besides your personal diving computer that is.

Your regulator should also be one of the first pieces of gear you purchase. Why? Well, how do you feel about using a mouthpiece that others have used and you have no idea who that might have been? Yes, it’s been cleaned but…

Scuba Diving Regulator Buying Guide

It’s also essential as one of your first items to get simply because it’s the part of your gear that allows you to breath. As that’s very important under water, you might consider it your possibly most important piece of gear overall! And, as it does allow you to breathe under water, you want to make sure you get a good piece of equipment and that you maintain it to keep it in good shape!

This buying guide will educate you on the different pieces of your regulator. These are the first and second stage, the octo and the hoses. Lastly, we’ll quickly touch on the different gauge options you have to control your air use and what you have left.

You will usually purchase your first and second stage regulators as a package. That makes sense as you want those two pieces to match and work flawlessly with each other! You’ll know exactly what to buy when you’re through with this guide.

First Stage

The first stage of a regulator for scuba diving is designed to reduce the air pressure from the tank into a more manageable pressure that can be used in flexible hoses. This pressure level is called intermediate pressure.

The Scubapro MK21 First Stage regulator is shown below. It’s an excellent example of a first stage regulator. Click below to check out what customers have to say about it.

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It is attached directly to the valve on the tank. Your tank has the air or gas mix under high pressure and the first stage regulates that pressure going into the hose right after that. The first stage is also the point where you attach your gauge for air pressure or your wireless air transmitter for your dive computer as well as your BC and octo!

There are some differences in first stages when you’re looking to buy. Here’s an overview of what you have to consider and what the different options mean for you.

DIN vs. Yoke

Your first consideration is the type of how you attach your first stage to your tank. Many regulators are available as either DIN or yoke.

We have a whole article highlighting the differences between DIN and Yoke. There should be no questions unanswered after you’ve read that post.

A DIN first stage screw directly into the tank valve. This is the safest way to connect your first stage to a tank valve. Not only does it sit safely due to being screwed in but it also restricts any movement of the high-pressure O-ring seal that prevents air from escaping. This system is mostly used by technical divers as it can handle higher tank pressures.

The yoke system is somewhat simpler but fully sufficient for recreational diving. In this setup the regulator is slipped over the top of the valve and then secured and held in place with a large bolt. It’s somewhat easier to handle and safe to use in recreational diving.

Most tanks that you can rent will have a yoke attachment. A DIN regulator requires a compatible tank and not all dive shops have them. However, if you have a DIN regulator you can get a simple and low-cost adapter to convert it to a yoke system if the tank does not allow to use a DIN regulator.

You definitely want to purchase such a converter if you opt to buy a DIN regulator. You might otherwise find out the hard way that the available tanks in the dive shop will be of no use to you!

Hoses attached to first stage regulator

Balanced vs. Unbalanced

In the past you had a pretty significant different in performance between these two types of systems. In the meantime most of these differences have been minimized and most (recreational) divers cannot distinguish once they’re under water.

The difference is simply in how they work and how much they cost. A balanced regulator delivers the air at a constant pressure to the second stage and the diver. It is in no way affected by the pressure of the water surrounding you or the pressure of the air in the tank itself!

An unbalanced system relies on the surrounding pressure as well as the pressure inside the tank. Modern unbalanced systems minimize those effects and you barely notice a difference.

Having said that, most divers prefer a balanced setup if they can afford it. Otherwise, opt for a high-quality unbalanced type and you’ll barely notice a difference in recreational dive environments.

Scuba Diver with Regulator underwater

Diaphragm vs. Piston

Yet again there are two different types of setups that are used to connect the high pressure air into lower pressure for the second stage regulator and other attachments. Both setups work fine for most recreational diving.

Piston regulators are overall simpler as they have a minimal amount of moving parts. This enhances the durability and reduces maintenance costs. However, most of these first stage regulators allow water into them and as such you have a higher level of care after a dive to keep them clean and prevent corrosion.

Diaphragm regulators have more moving components and usually are not as durable as piston regulators. However, they are much cheaper to manufacture which usually results in a lower price for you.

They come in two different flavors. You can get them either as environmentally sealed or unsealed. If you only dive in the tropics then an unsealed regulator is perfectly fine. If you want to mix up your dive environments then you’re better off using an environmentally sealed setup.

For a recreational diver it makes the most sense to look for an environmentally sealed first stage diaphragm regulator that has a long warranty. Also make sure to use a well-known brand so you know you can get spare parts if needed!

First Stage Regulator on Tank

Number of Connection Ports

Most modern first stage regulators will have enough ports to allow you to connect your second stage, your gauge or computer and your BCD as well as a port for the octopus regulator if needed.

If you dive with a dry suit or need more ports to connect additional accessories and devices then you have to make sure that your first stage has enough ports to handle everything want to connect!

Second Stage

The second stage is the piece of the setup which you have in your mouth and that allows you to breathe. You’ll often see this second stage being referred to as the regulator. It takes the air from the first stage (through a hose) and reduces the pressure so you can comfortably breathe.

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Similar to the first stage you can either have a diaphragm or piston setup in your second stage. Your second stage also has a purge button, a mouth piece and an exhaust valve. The purge button allows you to clear any water from the setup. The exhaust valve allows your exhaled air to escape and finally the mouthpiece allows you to keep the regulator securely in your mouth without having to hold on to it.

But there are additional things to consider and look for when you’re looking at the second stage.

Purge Button

The purge button is there to allow you to clear your regulator. Pressing it forces the water out of the second stage so you can breathe easily.

You want to make sure that your regulator has a large enough purge button so that you can conveniently press it when needed. If the button is too small then you might have to fumble trying to press it if you’re wearing dive gloves.

Diver with Second Stage Regulator


You can often find a number of controls on your regulator. First, you can have the possibility to adjust the air flow so you can fine tune the amount of air being delivered for your breathing. This is helpful when you dive deeper as it allows to make sure that you can comfortably breathe.

Another adjustment that is commonly found is to be able to set the regulator into ‘dive mode’. If you switch this mode off while you’re above the surface then it prevents air to free flow. It’s harder to breathe in that case but you’re not wasting air.

These adjustment controls are in most circumstances ‘nice-to-have’ features that you can live without especially if you’re recreationally diving.


The weight of the second stage can be of importance to you. It’s the piece of equipment that you hold with your mouth and teeth and it can over time cause fatigue of the jaw.

Overall, the second stage is of neutral buoyancy and as such the weight under water should be of limited concern. However, above water a heavy regulator can be somewhat tedious to wear and deal with.

First Stage Regulator with Hoses

Mouth Piece

The mouth piece must fit comfortable. Most modern second stage regulators have ergonomically shaped mouth pieces and as such you should be fine.

For repairs you want the mouth piece to be replaceable. This is pretty much true for all new regulators but you have to have a look at how the mouth piece connects to the rest of the hardware. You can find proprietary mounting options or zip ties. In any case, you want to make sure you have the right spare parts in your repair kit!

Octopus Regulator

The octopus is nothing else than a spare or alternate second stage regulator. It is used to allow your dive buddy to breathe if he or she runs out of air or if your second stage regulator fails for whatever reason.

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These octo regulators are only to be used as a backup and as such are usually less complex and of simpler design as your primary second stage regulator. In a typical dive setting you will never use your octo as it’s only there for emergencies.

Dive standards do require that the octo is easily accessible and clearly visible. Most octo’s are bright in color to make them stand out and to be easily identifiable. Most of today’s BCD’s also have a pocket to store the octo for easy access in case of an emergency.

If you want to read more about Octo regulators and which different kinds there are, then please check out our post on that: https://www.deepbluediving.org/scuba-octopus-regulators/

One of the things that is easily overseen with octo regulators is that they require the same care and maintenance as your other gear. Make sure to keep your octo clean and perform all pre-dive and post-dive checks and maintenance steps that you also perform on your standard second stage regulator!


Your regulator setup not only consists of the first and second stage but also comes with a bunch of different hoses to connect both stages as well as additional accessories.

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Hose to Connect First and Second Stage

This is usually a medium pressure hose that is used to connect the two stages. For many years the only available option you had was a rubber hose.

In the last few years many manufacturers started to provide braided hoses. However, there has been a few instances where these types of hoses had to be recalled and as such divers today still tend to prefer a rubber hose.

A braided hose has some advantages though. They are usually lighter and more flexible and as such more convenient to deal with. A new braided hose should also be more durable than a rubber hose.

Inflation Hoses

This type of hose connects the first stage to your BCD. You’ll need this link in order to be able to regulate your buoyancy through your BCD. You can either get a rubber hose or braided hoses which are lightweight and bendable.

Some BCD’s come with an octo regulator built into the inflator. In that case you will usually require a special connector. You want to be aware of that when ordering your hoses.

Second Stage Scuba Regulator

Hoses for Gauges and/or Dive Computer

You will usually have at least one gauge to monitor your tank pressure. Some divers prefer to use a analog gauge as well as a dive computer with air integration to monitor the pressure in their tank.

These hoses are usually high pressure hoses. If you’re choosing an air-integrated dive computer that has a wireless setup then your pressure monitor will sit directly on the first stage and wirelessly send the data to your dive computer. This will save you from dealing with yet another hose. However, it does make some divers uneasy to think of a non-mechanical way to measure how much air is left!


Most of the well-known brands will have regulator setups that are sufficient for any recreational diver. If you can then spend a few extra-bucks to get a setup of the highest quality. If you get a first stage with a DIN connector then make sure that you do purchase an adapter to make it usable with a yoke connector to ensure you won’t have to watch your buddies dive while you stay on land!

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