Help Choosing a Regulator

Finding a Scuba Regulator To Meet Your Needs

Choosing the right regulator can be quite a daunting task, with an array of performance features and industry acronyms that can be confusing.

To help you better understand some of the commonly talked about terms, we thought we would break the Regulator down into its key components and give some advice in what to look for;


First stage

This is the bit of the regulator that attaches to the Divers Tank, it’s role is reduce high-pressure air to an Intermediate pressure (around 10 BAR) for delivery down the low-pressure hose to your second stage. There are 2 types of first stages available;

  1. Piston first stages use a Piston that opens and closes on a High-pressure seat. Most people choose a Balanced Piston when buying this model to ensure air delivery isn’t impacted by cylinder pressure. Balanced Piston regulators are well regarded for the volume of air they can deliver to the 2nd stage and are quite popular with Tec Divers for this reason. Most Piston regulators are constructed out of Chrome Plated Brass, but some brands do offer Lightweight Titanium and Atomic Aquatics also bring out a Stainless Steel model. Piston regulators offer good house routing and often have a low-pressure swivel turret. Most use holes in the Piston Chamber to adjust to ambient pressure as you dive, this means Saltwater if you are Ocean diving enters into the working parts of the Regulator. Due to this, the regulator should be well soaked after use. Some regulators like Atomic have a sealed option that eliminates water entering this chamber. We strongly recommend choosing this option if you choose a Piston regulator as this design will maintain high performance and longevity between services.
  2. Diaphragm first stages only come in a Balanced version and use a Diaphragm and Spring that pushes on a Pin to open and close the High-Pressure seat as you Breathe. Diaphragm Regulators can be quite compact in design. Entry level regulators are usually machined in a CNC lathe out of a Rod of Brass and then Chromed. High-end performance Diaphragms are usually cold Forged and pressed into shape, this leads to better hose configuration and smoother Air delivery due to optimized air flow.

At Abyss, we prefer the Diaphragm models that have an additional Environmental Cap that sits over the Diaphragm to ensure no water enters into this part of the regulator. Just like the sealed Piston example above this maintains high performance and longevity between services.


Second stage

The 2nd stage takes the intermediate air delivered by the 1st stage and further reduces it to ambient (surrounding water) pressure. There are 3 types of valves used by manufacturers on 2nd stages;

  1. Demand Valve this is the simplest of valves that opens when you breathe in and closes when you exhale. They are generally sold on Occy’s and entry-level regulators
  2. Balanced Demand Valve, this valve uses a flow-through seat retainer that ensures even air pressure at both ends of the valve. This allows for a lighter spring tension making for easier smoother breathing.
  3. Servo Valves, these aren’t common but are an amazing design that outperforms the traditional valves in terms of air delivery. The valve is balanced by design and uses a diaphragm that when opened delivers the air out of 6 independent holes in the valve rather than the single hole on the standard demand valves. This valve is usually housed on side breathing regulators that have the advantage of the exhaled bubbles not obscuring your vision when diving.


Adjustable 2nd stage

 To add further confusion to the offering Demand and Balanced Demand valves are also available in an adjustable option, this means that you can adjust the valve spring tension by turning a knob positioned on the side of the regulator. This way you can fine tune the regulator to your desired breathing performance as you dive.


Pre Dive Switch

 Most 2nd stages have some form of Pre Dive switch, this is a lever or dial usually easily accessible with a gloved hand that you turn on when you enter that water to avoid Regulator free flow and valuable air wastage on the surface. Upon descent, you should turn the switch open to allow for the optimum flow of air during the dive. The switch works by deflecting air away from the mouthpiece hole in the regulator and stopping the regulator from creating a Venturi. Atomic Aquatics use an automated Pre Dive switch which is pretty cool as we notice that lots of divers forget to use their pre-dive switch and often have it set for harder breathing.



 Quality regulators have a flow vane positioned inside the 2nd stage that pushes the flow of air towards the oral breathing channel (mouthpiece), this, in turn, creates a Venturi effect with the remaining air inside the 2nd stage also wanting to flow towards this low-pressure area. It’s a simple but clever way to improve performance and make your regulator easier to breathe.


Work of Breathing

 This stands for Work of Breathing and is a measurement that most Scuba brands now use to measure the performance of your Regulator. The is a measure of energy (Joules) and takes into consideration the many factors across a breathing cycle including Inhalation and Exhalation effort. Generally, the lower the number the higher the regulator performs, as a rule, any number lower than 1.0 j/l is recognized as a good performer.



 The servicing of your regulator is important, after all its life support equipment!

Servicing can be a significant cost and should be considered in your decision-making process. Two of the brands we sell offer Free Parts for life and they are the only brands offering this fantastic saving in Australia. When you buy a Hollis or Oceanic regulator you only pay for the Labor, not the Parts. This is a saving of approx. $1000 over 10 years so is definitely worth considering.

Due to the materials used in construction, namely Titanium and or Stainless Steel Atomic Aquatics offer a 3 year or 300 Dive service interval on their 2 flagship regulators, this also leads to a significant saving in service costs


If you have got to this part it means you should now have a better understanding of some of the Scuba Industries Regulator jargon and can start to look for a regulator that is best going to suit your Diving needs, click through to the next Regulator pages to see what models we have available.

If you have any questions please call one of our friendly Dive Instructors who will be able to answer any queries you have. Better still drop in store and we can get you out on a Try Dive with your in-store Regulator of choice to see how it performs.