How to choose a diving regulator? Everything you want to know. A practical guide.

The diving regulator is one of the most important elements of our diving equipment. The right choice of regulator, correct service and proper use increases our safety under water. A good diver should not only know how to properly connect the respiratory regulator to the tank, but also how the diving regulator works. So let’s start by explaining what a diving regulator is and how it works.

Diving regulator – construction and principle of operation.

The diving regulator consists of several elements that can be bought together or separately. The regulator’s basis is:

  1. First stage – the first stage of the regulator is screwed to the diving cylinder. Its task is to reduce high pressure from the cylinder to about 10at of hypertension. The first stage can be membrane or piston, it can have a DIN or INT connection, it can work with a pressure of 200at or 300at.
  2. Second stage – reduces pressure from approximately 10at of excess pressure to ambient pressure. This element is located directly at the diver’s mouth.

In addition, the diving regulator must also have the following components:

  1. Octopus (alternative air source) – currently required – you cannot dive without an alternative air source. It is usually yellow so that it can be found quickly.
  2. Pressure gauge or console – the pressure gauge allows you to control the supply of air (or other gas) in the cylinder. If, in addition to the manometer, there is an additional indicator, such as a compass, depth gauge or dive computer, it is called a console.
  3. Hose to inflator – allows connecting the regulator to BCD
  4. Dry suit hose – allows you to connect a dry suit. It is not needed if you do not use a dry suit.


How to choose the right regulator for diving?

Choosing the right regulator for diving is not a simple matter, and the market offer is very rich. The most popular companies selling diving equipment include Apeks, Scubapro, Cressi or Mares.

Currently, all manufactured regulators meet fairly strict technical standards and are suitable for recreational diving up to a depth of 50m. If you are not sure what type of regulator you should choose, you will certainly get advice at your nearest diving equipment store.

The offer of diving equipment manufacturers is very wide and everyone is trying to come up with new technical solutions to encourage customers to buy. So what should you consider when buying? I suggest the following criteria:

  1. Price. Price is an important parameter, but it should never be a decisive factor. You should follow the rule to buy the best equipment you can afford. However, this does not mean that the most expensive is the best. Also remember that diving equipment is not bought for one season. Always buy good quality equipment.
  2. Purpose. Here I mean the conditions in which the dives will be conducted. If you dive rarely and in clean and warm waters at small depths, a simple and cheap regulator is enough. For example Scubapro KM2 / R190 or similar. It is a piston regulator with a very simple design on both the first and second stages. Due to high reliability and low price it is widely used in diving schools.

    If we conduct deep dives, the regulator should be characterized by high reliability and low breathing resistance. For such a dive, choose more expensive breathing regulators.

    Regulators with good frost protection are best suited for cold water. Theoretically, you can attach this protection to any regulator, however it is best when this solution is already installed.

  3. Service availability and price. All diving equipment requires periodic maintenance. When you buy a diving regulator, it’s worth finding out if the service for this model is easily accessible. If you are thinking about buying used equipment, be sure to check if there will be problems with access to service
  4. Equipment of your colleagues. Ask your colleagues what equipment they are using. Tips from more experienced divers and instructors are a good way to choose the right diving equipment. Your colleagues will help you choose the best equipment. Rather, avoid equipment that is not very popular.
  5. Technical requirements. Technical requirements are the most important parameter. If you do difficult dives, the regulator should be the best. Technical divers choose the most reliable equipment that reduces breathing resistance at great depth.

Output port setting.

The output port is a place where we can connect to our regulator: manometer, inflator, octopus. The ports in the diving regulator can be distributed symmetrically over the entire circumference or on both sides in parallel.

The ports are standardized and the differences in their sizes are so large that there can be no mistake in connecting the hoses. You cannot screw a medium pressure hose into the HP port. Most diving regulators have six ports:

  • 2 HP ports (high pressure) UNF 7/16 “thread. Cheaper regulators have only one such port, which is enough because we mount one pressure gauge to one regulator.
  • 3-4 LP ports (medium pressure), UNF 3/8 “thread
  • 1 LP port UNF 1/2 “thread for the second stage of the regulator. This solution is not used in cheaper regulators. Increasing the diameter is to reduce breathing resistance.

Piston regulator or Membrane regulator?

We have to decide if we want a piston regulator or a membrane regulator. The difference lies in the construction of the regulator, and more precisely its control element.

It is an element that reacts to pressure changes and opens the first stage reduction system of the regulator. This is related to the construction of the regulator, and the difference looks like this:

The disadvantage of piston regulators is the lack of a simple regulation of the average pressure value, and problems with frost protection.

The membrane is the most common system. It is used successfully in the first and second stage of reduction. The piston is only used in the first stage.

Pros and cons:

Membrane regulator

+ easy regulation of average pressure

+ good protection against external freezing

– more complicated construction

– possibility of deregulation under the influence of low temperature

Piston regulator

+ very simple design

+ small amount of elements

– no good protection against external freezing

– difficult regulation of medium pressure

Connection of the regulator to the tank – DIN or INT

Another element that you need to pay attention to when buying a regulator is the standard of connection to the tank. There are two basic standards in the world when it comes to the cylinder valve output port:

DIN – in this case the output socket has a G 5/8 “internal thread. The regulator has the same thread, but external. The seal is made on the O-ring after screwing the regulator to the end of the socket. The O-ring is located in the regulator socket, type DIN divided into 200at and 300at. Valves for 200at have a short thread and 300at long thread.

INT – also called a yoke because of its characteristic shape. In this solution, the seal is also made thanks to the O-ring, but the O-ring is located in the cylinder valve seat, and the contact surface of the cylinder and the regulator is flat. INT connections are used up to a pressure of 200at.


Reducer from DIN to INT and INT to DIN.

Because both systems are used in the world, a reduction has been invented that allows the two systems to be connected. In this way, we can use the DIN regulator with the INT tank and vice versa.

It’s hard to say which type is better because they differ from each other. It’s definitely worth having your own reduction to be able to use your own equipment everywhere in the world.

Diving regulator – summary

The above study is only part of the knowledge about scuba regulators. As you can see, to make a service for a diving regulator you must have experience and training.

That is why it is so important to choose good quality equipment. If you need advice regarding diving equipment, please contact us and we will certainly help you choose the right equipment.


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