Everything You Need to Know...The Regulator Buying Guide

Your regulator is the heart and soul of any SCUBA Diving setup. Unless you can hold your breath for over 10 minutes then you’re going to want reliable breathing apparatus to deliver air, safely and comfortably, no matter your diving level.

But what exactly is a Regulator, and what do you need to know before buying one?

First up.

What is a Regulator?

That’s a really good place to start isn’t it? A regulator is the term we use to refer our entire breathing apparatus system. It’s know as a regulator because its main role is to regulate your gas supply, reducing the extreme air pressure of your tank down from a tremendous 232/300 bar to a safe and breathable air pressure.

The Anatomy of a Regulator

anatomy of a regulator

Regulators or Regs are comprised of 3 main components:

The First Stage

As we’ve already mentioned your first stage connects directly to your tank. It was never going to be that simple though, was it?

First Stage Fittings

There are two types of connections used to attach your first stage to your tank

  • A-Clamp or Yoke fittings are by far the more common fitting and have been around since the beginning of modern SCUBA. While they’re perfectly safe, A-Clamp fitting are limited to 232 bar tanks and can’t be used with 300 bar tanks at all.
  • While A-Clamps have been the prevalent design in diving they’re beginning to be replaced by the more modern and safe DIN fitting. DIN connections are lighter, allow for much higher air pressure and are less bulky and are less liable to small leaks, while can occur with A-Clamps slightly less secure fitting.

Luckily a technician can convert your DIN regulator to A-Clamp and vice versa, so your decision isn’t final. Similarly, you can adapt DIN regs to A-Clamp regulators with an adaptor, and we’d recommend going down this route as it provides the greatest flexibility and performance.

Regulator Clamp types

Balanced Versus Unbalanced Regulators

One of the choices you’ll make when buying a regulator is whether to purchase a Balanced or Unbalanced regulator. In this past this used to be a big choice. Balanced regulators were expensive and performed significantly better at depth. These days that gap has been bridged somewhat and should pick whichever you prefer - though most people err towards balanced regs because of their easier breathing.

  • Unbalanced regulators are affected by water pressure, increasing breathing resistance as you descend. More significantly, as the gas in your tank becomes depleted breathing effort also increases. Some divers like this as it gives them a heads-up when they are running low on gas (it’s never an excuse to not check your gauges though!)
  • Balanced regulators provide a more consistent supply gas regardless of depth or how much gas is left in your tank.
  • There is a third option called ‘overbalanced’. These regulators increase the flow of gas as the diver descends further making them ideal for deep diving. These systems can be prone to freeflow due to their increased sensitivity, so like any tool, they take a little bit of adjusting too.
  • All current Diaphragm Regulators are Balanced or Overbalanced.

Piston vs Diaphragm Regulators

Most divers shouldn’t get too worked up about whether their first stage uses a piston or diaphragm design to reduce the incoming gas pressure. The difference in performance is negligible - Piston regulators offer minor performance benefits at depth while diaphragm regs can be sealed more easily, making them suitable for cold water diving or in silty, contaminated conditions.

1st Stage Ports

Ports on the Apek XTX 1st Stage - High and Low Pressure Ports use different fittings ensuring you can't mix them up.


Regulators use two types of ports, High Pressure and Low Pressure ports - sometimes listed as Mid-Pressure ports for reasons we can’t quite fathom.

  • All regulators have at least 1 high-pressure port which is used to connect your pressure gauge. Many first stages have two. This allows you to run an extra gear, such as a transmitter for your dive computer.
  • Low-Pressure ports are used to hook up your second stage, octo, BCD inflator and any other pieces of equipment you have, like a drysuit inflator, if required.. Make sure you get a first stage with enough ports. Having too many is never going to spoil your day, having too few, definitely will.

Environmentally Sealed First Stages

We’ve touched upon this very briefly already, environmentally sealed first stages are sealed to prevent water and silt getting in. This prevents the first stage from freezing open in cold water, which results in a freeflow (When your regulator sticks wide open, making it feel like you’re breathing in a jacuzzi). Secondly, it stops silt, bacteria and dirt getting into your system, meaning it needs less maintenance, cleaning and is potentially safer.

Unless you’re flying light with your regulator to dive in tropical waters where none of these issues are a concern we’d recommend an environmentally sealed regulator.

Regulator 2nd Stage

Balanced vs Unbalanced

You might come across the question of balanced and unbalanced second stages, luckily all modern second stages are now balanced in design - that's one thing less to think about!

Opening Effort Control/Cracking Adjust

Opening Effort controls are less common than venturi controls, and if you regulator doesn’t have one, this is set by a diving technician during setup/servicing. Opening effort works by adjusting the spring load of the mechanism within your second stage. In laymans terms this allows you to fine-tune how hard or easy it is to breathe through your regulator.

Venturi Control

You might have noticed a wee lever on your regulator labelled something like ‘+/-’, ‘Dive/Pre’ or ‘On/Off’. This wee lever allows you to turn on or off what’s known as the ‘Venturi Effect’ in your second stage. Turning it on makes breathing practically effortless on any decent regulator.

However, the venturi effect means the regulator requires much less pressure to activate, meaning it’s rather easy to freeflow, especially when at the surface. Turning Venturi off helps you prevent this.


Arguably your mouthpiece is one of the most important parts of your regulator. An uncomfortable one will spoil your dive surprisingly quickly. Luckily they’re easily swapped!


Your Octopus fulfils the role as a backup gas supply should your primary second stage fail (this is thankfully extremely rare!). It functions in exactly the same way as any other second stage, delivering breathable air to your mouth. Unlike your second stage they’re highlighted in bright yellow to ensure they’re visible in low light. They also have much longer hoses allowing your diving buddy to access it easily if they get stuck.

Generally you don’t need a flashy Octopus so they’re typically cheaper, and less highly spec’ed in comparison to your Primary 2nd Stage

Our Recommendations

AquaLung Core Supreme

AquaLung Core Supreme

AquaLung Core Supreme

A true workhorse. The Core Supreme does everything you ask (and a little bit more!) of an entry level regulator swimmingly

Made to handle sub 10*c water conditions, it's equally capable in UK waters as it is abroad in warmer climes.

The Core Supreme is pneumatically balanced, meaning it breathes easily throughout your dive, while the venturi control ensures you can prevent freeflow at the surface.

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Apeks XTX200

Apeks XTX200 Regulator

Apeks XTX200

A homegrown UK brand, Apeks have built their reputation on bulletproof, easy breathing regulators designed to take on the challenges of UK diving. The XTX200 fits into the mid-high end of Apeks range and as you'd expect, it offers effortless performance and the build quality to shrug off the abuse the north-sea can throw at it.

The XTX200 is packed with bells and whistles too: venturi control, on-the-fly cracking adjust, a comfo-bite mouthpiece (that helps reduce jaw fatigue), and the ability to function in brutally cold conditions

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