How to Choose the Right Diving Regulator

How to Choose the Right Diving Regulator

Your scuba regulator is a big investment, likely the priciest gear you'll purchase for diving, and undoubtedly the most important! Serving as your lifeline and breathing source underwater, it ranks high among the most vital buys for divers. Once you own one, it's hard to return to rental regulators! So, getting the right one is important. This post will help you understand your options before you make a purchase.

When we mention the regulator, we talk about the entire delivery system, which includes few components:

  • First Stage: The main hub
  • Second Stage: Where you breathe from
  • Alternate Air Source: Known as the 'octopus' for emergency use by your buddy
  • Low-Pressure Inflator Hose (LPI): Connects to the BCD
  • Console/SPG (Submersible Pressure Gauge): Provides diver information
Scuba Diving Regulator

When purchasing a regulator, you can go for a package deal or buy pieces separately. This flexibility lets you mix and match brands and models to find what works best for you.


The first stage of a dive regulator

The first stage of a dive regulator the boss that connects to the cylinder and lowers the tank pressure (200 bar) to an intermediate pressure (around 10 bar). There are several variants of the first stage: 



DIN Versus Yoke Diving regulators

Similar to how countries use different socket types, the first stage comes in two fitting options: DIN or Yoke (A-clamp/INT). The 'yoke' design places the o-ring in the tank, while the 'DIN' has the o-ring in the regulator. A DIN regulator screws into a DIN tank valve, and a yoke regulator attaches to a yoke tank valve. While the yoke design has been the standard for diving from the beginning, the DIN design, initially intended for technical divers, is gaining popularity worldwide. DIN provides a more stable and secure connection, as it screws directly into the tank valve, according to many divers.

Connection options for DIN and Yoke fittings:

Adapters can be used for both, so you need not worry about your choice. However, the easiest option is to buy a simple adapter for the DIN regulator, allowing it to fit on either tank valve.

DIN-YOKE Adapters
  1. An insert can be used in a DIN tank to accommodate a Yoke regulator.
  2. A Yoke attachment can be screwed onto the DIN regulator to fit onto a Yoke tank.


2. Mechanics:

The first stage of a dive regulator utilizes either a piston or a diaphragm mechanism to reduce tank pressure.

  1. Piston Regulator:
    • Less protected from the elements.
    • Water enters the first stage and presses on a piston.
    • It is suited more for depth, as increased depth applies more pressure to the piston.
    • It contains only one moving part, making it easier to service.
  1. Diaphragm Regulator:
    • Works with a lever pushing against a membrane in an air space.
    • Better protected from the elements.
    • It is generally better for cold diving due to its design.
    • It contains more moving parts, making servicing more complex.

Another option is to purchase a regulator with an Environmental Seal, which protects the first stage against the elements and prevents freezing in cold water.


3. Ease of Breathing:

... This is where your budget will be a determining factor!

The basic option is the unbalanced regulator.

With an unbalanced regulator, a diver may have to use more physical effort to pull a breath as tank pressure or ambient pressure decreases. In simple terms, an unbalanced regulator may require slightly more breathing effort by the diver at greater depths or when the tank is low on pressure. 

  • Affected by water pressure, breathing resistance increases with depth and decreases as the gas in the cylinder decreases. 

Balanced Regulator:

The pressure coming from the tank and the ambient hydrostatic pressure from a diver’s depth do not affect the regulation of the intermediate pressure chamber in the first stage.
In simple terms, a balanced second stage regulator breathes the same at any depth and at any tank pressure
  • The regulator compensates for pressure changes.
  • Consistent breathing resistance regardless of depth or gas level.

Although a balanced regulator might seem like the superior choice at first glance, there are many high-quality unbalanced regulators available that perform exceptionally well. In reality, most divers can't discern a significant difference between the two types. 

Overbalanced Regulator:

These regulators allow the inter-stage pressure in the hose to increase more than a balanced regulator at depth.  This compensates for the increased density of the air at depth, allowing larger volumes of air to the diver, resulting in improved breathing performance.
  • Technical or deep divers favor it.
  • Increases flow as pressure increases, making breathing easier at depth.
  • It is more prone to free flow, which may be challenging for newer divers. 



The first stage of the regulator is where all the hoses connect. A standard regulator usually has 2 high-pressure ports and 3 low-pressure ports. Low-pressure ports are for the 2nd stage, alternate, and inflator hose. If you use a drysuit, you'll need an extra port to inflate it. High-pressure ports need at least one port for the pressure gauge or 'console.' If you use a computer transmitter, having an extra port is helpful. Basically, the more you spend, the more ports you get.


The second stage of a dive regulator

second stage diving regulator koh tao

The second stage (and alternate) reduces the intermediate pressure from the first stage to atmospheric pressure, which you breathe through. 

Again, there are a few different options available. Some regulators feature an adjustable knob to control breathing ease, while others offer more comfortable mouthpieces. However, you can also purchase mouthpieces separately at a relatively low cost. Mouthpieces come in standard fit, comfort/orthodontic, or mouldable options, and the choice depends entirely on the diver's preference.

The alternate or octopus is the same as the second stage, but it is there for your buddy in an out-of-air emergency. For this reason, it is often brightly colored, usually yellow, and has a longer hose.


The console/ SPG (submersible pressure gauge)

The SPG measures gas in the cylinder. It is available in digital or manual and measures gas in bar or PSI. It can be bought alone or with options like a depth gauge and/or compass. Some prefer a wrist-mounted compass, while others like all-in-one consoles. More gadgets mean a higher price!


Tips from Coral Grand Divers Team: Today, dive stores offer regulators from major brands, all built to high standards. Even budget options boast impressive performance, thanks to technological advancements. Focus on performance; the best regulators provide ample air volume, even at low tank pressures. Consider models with adjustable airflow for your primary air source, a technology pioneered by Aqua Lung and now widely available. When choosing your alternate air source (octopus), prioritize higher breathing resistance to prevent free-flowing, considering it as a backup to your primary regulator. While a comfortable mouthpiece matters, don't let it dictate your choice! Remember that mouthpieces can be customized or replaced separately. Some divers opt for moldable mouthpieces for long-lasting comfort, though they may come at a higher cost. Conduct thorough research and seek advice from dive shop staff and experienced divers before purchasing!


Here at Coral Grand Divers, we offer a range of rental regulators, including the Aqualung Calypso, PSI Maui, and Scubapro MK2 EVO R095. These regulators are perfect for various diving activities, from trying scuba diving and exploring to learning to scuba dive and expanding skills in the warm tropical waters of Koh Tao.


Here's a glimpse into the Regulators some of our staff members use :

• Elise from France: Cressi Master set

• David from the UK: Scubapro MK25 / G620

• Yohan from France: Scubapro MK25 / G620

• Cedric from the Netherlands: Scubapro MK25/ S600

• Jules from Germany: Aqualung Mikron set

• Tan from Singapore: Aqualung Titan set

• Greg from France: Apeks MTX-RC set

• Linda from China: Scubapro MK25 / R600

• Charles from Belgium: Aqualung Helix set

• Joy from India: Aqualung Legend Elite set

• Maria from Spain: Aqualung Titan set

• Jerome from France: Scubapro MK11 C370 set

• Clark from China: Apeks XTX 200 set


PADI 5 Stars IDC Center

More than 50000 PADI Certifications


Our team is at your disposal for any questions about our articles or your order.


The management of our online payments is 100% Secure with Stripe


Free Shipping in Thailand

This website uses cookies to ensure you get the best experience on our website.