Regulators – a quick guide

The Apeks XTX50 in a left hand configuration

The Apeks XTX50 in a left hand configuration

The next item on my shopping list of kit is a set of regulators. I have been looking at getting a set since I was in Malta and I have done quite a bit of research into them.

There are so many different types and kinds of regulators to choose from: how does one cut through all the information and work out what to buy?

I do recreational and “tec” side mount diving. So anything that I buy I want to be usable for technical or recreational diving.

So what should you consider:

First Stage

This is the most important part of your set up. This is the the part of your kit that connects to the cylinder. It converts the pressure in the cylinder, which can be up to 300 bar down to a more usable pressure 10 bar. The first stage will have at least one high pressure port that you can attach your SPG (submersible presure gauge) to a transmitter for your dive computer.

First stages come in two types: Diaphragm or Piston.

Diaphragm first stages are more complex and they are usually environmentally sealed. Environmentally sealing a first stage allows it to be used in cold water by stopping ice crystals from forming

Piston first stages have less moving parts so they are more efficient than diaphragm models. However, only the top end models are usually environmentally sealed, the lower models are coated in special materials to protect them.

The first stages come either balanced or unbalanced. The balanced first stages deliver the same pressure to the regulator regardless of depth or pressure remaining in the cylinder; unbalanced ones do not. Though recently unbalanced ones have become better at dealing with this, balanced ones still continue out perform them. Unbalanced stages are cheaper, and it can be harder to breathe from them at depth.

Ports are what allow the first stage to pass on the reduced air pressure to the regulators, SPGs, inflater hoses and dive computer transmitters. Most entry models come with 3 low pressure ports (for main regulator, octopus and the BCD), if you plan on diving with a drysuit then you’ll need another low pressure port so that you can inflate it. So buy a first stage with at least 4 low pressure ports and one high pressure port (for the SPG).

DIN or INT? You may have heard about this debate at your local dive shop. DIN is gaining ground on INT (or A-clamp). It has predominantly been used in the tec diving scene but is now becoming the choice du jour in Europe and the rest of the world. DIN is better as it traps the o-ring between the cylinder valve and the first stage. This means there is less chance of wear and tear and you are less likely to suffer a blow-out.  With DIN you can use a converter so you can use an INT (A-clamp)  configured cylinder. DIN also allows up to 300 bar of pressure, whereas INT can only take 232 bar. I think you can guess which one I would choose.

Second Stage

The second stage converts the the pressure from the first stage into breathable ambient pressure. These come in balanced and unbalanced versions. This is similar to the first stage so choose a balanced one over an unbalanced version, as it will be easier to breathe from.

Depending on the second stage it may have venturi controls and inhalation adjustment. The venturi controls help to stop free flow when you are entering or are at the surface. Inhalation adjustment allows you to change the rate of flow of the air coming through the second stage, meaning if it is getting harder to breathe through the second stage you can open it to make it easier.


The SPG attaches to one of the high pressure ports, it tells you how much pressure is left in your cylinder so obviously it is an important piece of kit. Some SPGs come with depth gauges, compasses and computers attached. It’s up to you how much you want to spend on your SPG, the more you spend the more that will come with it. I prefer having a manual SPG attached to my first stage, this is because it is not electrical and it is less likely to break under water. I have a separate compass and computer (both made by Suunto).

I hope this has given you some insight into the different types of regulators that you can get.

I have chosen to get Apeks XTX 50s with a 5 port first stage. These are balanced first and second stages. This first stage can be used when doing sidemount diving and the second stages are standard tec diving regs.  Just waiting on them to arrive, they should be here in time for my dive trip to Porto Ercole.

2 responses to “Regulators – a quick guide

  1. Pingback: Advanced Open Water Diving – Porto Ercole | Jump - Sail - Dive·

Leave a Reply

Please log in using one of these methods to post your comment: Logo

You are commenting using your account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s