Choosing Regulators for Technical Diving

Although we’ve discussed buying a recreational-scuba regulator, we’ve never delved into choosing regulators for technical diving. Here’s what you need to know.

Buying recreational diving equipment is both daunting and exhilarating, and it’s no different when it comes to technical diving equipment. We took a look at the topic a little while ago, and here we’re going to delve a little deeper on how to go about choosing regulators for technical diving.

The basics

As a recreational diver, you may already own a set of regulators. Generally, this consists of a first stage, two second stages — one of which is mounted on a longer hose — a high-pressure hose for your submersible pressure gauge (SPG) and maybe a console plus one or two low-pressure inflator hoses for your BCD and your drysuit, if you’re diving in cold waters.

As an open-circuit technical diver, you will be carrying more than one tank, and consequently, you will be using more than one set of regulators. Each set has slightly different components depending on its purpose, but all will consist of a first stage, a second stage and a high-pressure hose with SPG — with one exception we’ll get to later in this post.

Which components are part of your individual regulators depends on when you are planning to use them on the dive. Roughly speaking, you can divide tech dives into three phases: the bottom part, travel to and from the bottom part, and the decompression phase.

Bottom or back-gas regulators

Bottom, or ‘back-gas,’ regulators attach to your twinset or your main sidemount tanks. While the term bottom gas is pretty self-explanatory, ‘back-gas’ refers to the fact that the twinset containing this gas is usually on your back.

Whether you are diving air, nitrox or trimix, these are the regulators that you will be using during the deepest phase of your dive, when your breathing gas is most dense and therefore hardest to breathe. That means you are looking for high-performance regulators that can deliver a lot of gas to allow you to breathe as easily as possible. Your choice of gas obviously influences breathing ease, but your regs have a role to play as well.

Regulator configuration

regulators for technical diving

The author models twinset configuration on a dive. (Credit Heather Sutton)

If you are diving twinsets, you need a first stage each for your left and right tank, also called left and right post. While there are some variations, most tech divers will have a second stage with a 7-foot (2 m) hose on the right as well as their inflator hose leading to their wing. The long hose connects to the second stage that tech divers generally breathe from. The hose is longer to allow divers to share gas and exit a restriction while swimming behind each other.

The left tank typically holds a second stage on a short regulator hose with a ‘necklace’ made from bungee cord or surgical tubing, as well as a high-pressure hose and an SPG. There may also be another inflator hose here for a drysuit or the second bladder of the BCD if it has one. The necklace allows the diver to easily reach their second stage in case they need to donate their long hose.

Did you notice there is no SPG on the right post? When diving manifolded (connected) twinset tanks, the diver accesses gas from both tanks through one regulator as long as the manifold isolator valve is open. This means that as long as there is no equipment failure, one SPG is enough.

Sidemount setups

Typical sidemount setup (credit Yvonne Press)

Sidemount setups can vary more as the configuration in general is more individual. One common option, however, is to rig the right tank with a first stage, a second stage on a long hose, and an SPG on a short high-pressure hose, usually about 6 inches (15 cm) long. There may also be an inflator hose for a drysuit or a second BCD bladder here.

On the left tank is a first stage with a second stage attached to a short hose and again equipped with a necklace. Often, there is an angled ‘elbow’ piece between the second stage and the hose, allowing divers to easily identify which tank they are breathing from. Additionally, there is a short high-pressure hose with an SPG and an inflator hose connecting to the sidemount harness and wing.

Many sidemount divers run their inflator across their body rather than over their shoulder. This means that suitable regulators often have a fifth low-pressure port at a right angle to the other ports. It’s also easier to streamline a sidemount setup by using first stages that have the capacity to swivel and therefore allow cleaner hose routing.

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Some manufacturers have started offering dedicated twinset and sidemount regulator sets. This is a good way to purchase all the bits and pieces in one go. In the case of twinset regulators for example, they might have low-pressure ports pointing downward at an angle for better hose routing. Sidemount sets will have swiveling first stages with five low-pressure ports, one of which is at a right angle.

Deco regulators

Regulators for the decompression phase of the dive generally feature a first stage, second stage on a somewhat longer hose (octopus length) and an SPG on a short high-pressure hose.

Tech divers use these regulators with oxygen-rich nitrox mixes to help accelerate decompression and, therefore, the units must be suitable for use with oxygen. In practice, this means choosing a regulator that is made of a material with a high flash-point – titanium, for example. The regulator must also be cleaned for oxygen use, and any O-rings and greases used in the process must be oxygen-compatible. Not every regulator will be suitable fresh out of the factory, so it’s important to check on this when you are buying your deco regs.

As we generally use these regulators on shallower parts of the dive, we can use unbalanced first stages. However, this is still life-saving equipment, so the general recommendation to buy the highest quality possible while remaining practical.

Travel gas regulators

Trimix divers usually use ‘travel gas,’ a breathing gas that does not contain enough oxygen to sustain life on land. Their components will often resemble deco regulators, although they may not need to be oxygen-clean depending on the gases the diver uses.

If all that sounds daunting, consider this: you can usually rent equipment for your tech courses from the instructor or shop that is conducting the course. Most budding tech divers qualify initially to dive a twinset or sidemount tanks for the bottom part of the dive and one deco gas, so that’s ‘only’ three regulators. Additionally, you may be able to reconfigure some of the components you already own.

Last, but not least, consider where you will be diving. If you’re going to be in cold water, make sure your regs are suitable for that. If you will be spending a lot of time in remote areas, some brands will be easier to maintain than others due to the availability of spare parts and service technicians.

The first step when it comes to choosing regulators for technical diving is to speak to your instructor and other tech divers about what they use. Spend some time researching before going on that shopping spree. One thing is for sure — as your tech diving journey continues, your gear bag will only expand.

How old is Your Regulator & Oldest lasting Regulator ??

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Before I spend my money on new regulators, I Just like to see which brand of Regulator last the longest.

Provided we care for the Regulators and do the annual maintenance How long does a middle – high end range regulator last ?

How old is your oldest functional regulator ?

Please list down the following

4) Religious Maintenance Chores:



1) Brand: Sherwood

2) Model: Classic

3) Year Bought: 2002 – It was originally purchased by a friend of mine in 1999 and never used.

4) Religious Maintenance Chores: Took it to LDS along with an Aqualung Octopus XLC(?) for inspection six weeks or so ago. I haven’t used it yet. I need an spg.



. . . when did they stop making them?

1) Brand: Scubapro

2) Model: Mk V/109

3) Year Bought: 2000

4) Religious Maintenance Chores: Rinse and let dry

Paid $50. Bought it for a hang tank.



Kind of goes with my answer to your BC question. I have a Sherwood Magnum reg that I got with the BC, early/mid 80’s vintage. It still works fine and I still dive it some. I replaced it for the same reason I replaced the BC, wanted a new one. I can still get parts and service on it and keep it as my backup. It does not have the preformance that my new one does (Zeagle/Apex) but it still does fine for quarry/shallow reef dives. Not likely that you can actually “wear out” any good quality reg.

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Rick Murchison

Trusty Shellback

“You can have peace, or you can have Freedom. Don’t ever count on having both at once.” (Heinlein)
“. they saw the deeds of the LORD, his wondrous works in the deep.” (Ps107:24)



I have a Conshelf 14 which was bought in about 1984 (I believe).

Maint = I service it once in a while, when the scintered filter looks like it could do some harm.

It still works a treat and goes on every dive that I use my pony. Though I am now going to build it up as a spare reg for trips as it is too good for a pony reg. Can’t beat the Conshelf for reliability I reckon (Though other regs are very reliable also).

I also have a very old water lung sport diver. I inherited that and I’ve not taken the time to find out when it was bought or made.

It still works though, I don’t dive as I dont have any lead on service parts for it.



I have an old Scuba Pro

not sure the model but I bought it in Hawaii in about 1983

It was the first design with an adjustable knob on the side of the second stage. has a metal face, and a srewed down clamp on the side to keep the face plate of the 2nd stage on

I have used it down to 250 feet, and have about 2000 dives on it.

I still use it on by recreation teaching rig for old times sake,

I service it about every three or four years.

The reasonable man adapts himself to the world. The unreasonable one persists in trying to adapt the world to himself. Therefore all progress depends on the unreasonable man.”
– George Bernard Shaw.



I own an oldish Dacor Pacer 950 1st with an XL 2nd. Not sure when they were made, but my guess is 10-15yrs ago. I bought it used for cheap as my first setup. The 1st stage (a balanced diaphragm design) still breathes like a champ and goes with me on every dive, coupled with a ScubaPro G200B. Overall a very well-breathing setup. The XL 2nd stage used to pull the Octo duty until recently, when it was retired to the spares duties. Still works fine, although its performance leaves something to be desired. Will likely end up on a pony bottle before too long.



I am the proud owner of an Aqua Lung da “aqua-master” 2 stage regulator, serial number 901231. It was imported from France by U. S. Divers Co. I do not know its year of manufacture, it was a gift I received in September from Tadpole. It is in perfect working order, but has never been overhauled. It is not the original hose.

My oldest single hose regulator is a U. S. Divers “calypso – aqua – lung” serial number 5911. It is also in perfect condition and has never been opened. It was also a gift from Tadpole. I received it in July of last year.

Sounds like you’re describing a Balanced Adjustable 2 nd stage.

The Devil’s in the details.

Disclaimer: All discussion of value, by me or anyone else, is opinion.

For a comprehensive approach to diving education, check out Scuba Educators International (SEI) Diving.

How to Know When to Replace Your Dive Gear

Quality scuba gear can last for years if well maintained, but it isn’t designed to last forever. Equipment problems cause 15% of scuba diving fatalities according to DAN . Sadly, these problems are mainly due to lack of maintenance and improper use of the equipment.

As a general rule, if your equipment makes diving more difficult or is uncomfortable: repair or replace it regardless of its condition. Dive gear that requires constant adjustment, or doesn’t fit makes a dive at best unpleasant and at worst dangerous. Read on for an equipment-specific list of reasons to replace commonly-owned dive gear.

BCD (Buoyancy Control Device)

A pinhole-sized leak can likely be patched by your local dive shop, but if your BCD has been patched repeatedly, it’s time for a replacement. Other signs of wear such as frayed straps or broken buckles, or constantly-leaking valves are good indicators the BCD has reached the end of its useful life.

If you have an older integrated-weight BCD, consider upgrading. Some of the early weight-integrated BCDs had complicated and cumbersome weight systems that aren’t as easy released in an emergency – compared to modern BCDs. Need a little help finding a replacement? Check out our Beginners Guide to Buying a BCD.

Dive Computer

Dive computer

Many divers can use the same computer for years and years, but there may come a time when the unit can no longer be serviced by a qualified technician. Don’t continue to use a computer or any other piece of equipment that cannot be properly maintained.

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Divers should also consider replacing a computer that no longer meets their needs. Introductory computers have a lot of great features, but aren’t suitable for technical diving. Similarly, the low-end computer you purchased as a new diver may have a small screen that’s hard to read and uses confusing symbols. New computers have large, easy-to-read displays that may cause you to wonder how you ever dove without one.

Dry Suit

A dry suit by definition is supposed to keep you dry. But if you find yourself repeatedly patching the suit, or notice signs of mold, it’s time for a new one. A broken zipper may also be reason for replacement. Read more about when to buy a new dry suit .


scuba diving fins from shutterstock

Fins are perhaps the longest-lasting piece of dive equipment. New features, or just plain losing a fin are the main reasons for replacement.

Another reason to replace your fins is if they aren’t meeting your needs. If a blade fin causes muscle cramps, consider switching to a more flexible split fin. Conversely, if your fins don’t offer sufficient propulsion, it may be time to buy stiffer fins.


The mask strap is typically the first part of a mask to wear out. If you find your mask no longer adheres to your face on the surface, it’s likely time to replace it.

After the mask strap, the mask skirt is typically the next part of a mask to wear out. The skirt is critical for a maintaining a good seal around your your face. Test your seal when out of the water by pushing the mask against your face without the strap around the back of your head. If you find your mask no longer adheres to your face on the surface, it’s likely time to replace it.

Lastly, a lens crack, even a small one, renders a mask unusable. Be sure to replace a cracked mask immediately.


The job of a scuba regulator is to provide you with breathing gas underwater. It’s arguably the piece of dive gear you should care about most. It can be difficult to detect problems with a reg since you can’t see the moving parts inside it. For this reason, it’s critically important to have your regulator serviced annually no matter what .

If you see cracks or bulges in the hoses, bring it in. Cracks in the plastic, no matter how thin, are also cause for concern. Lastly, a free-flowing or hard-breathing reg needs to be checked right away.

Just as a car needs its oil changed and timing belt replaced, your regulator can’t function properly without a regular tune-up. If your regulator is so old it can no longer be serviced, it’s time for a new one. Also, if you find your old regulator causes excessive jaw fatigue, consider investing in a new one that’s compact and made of lighter materials.


Snorkels are fairly sturdy and can last a long time. The mouthpiece and hose portion are the most likely areas where damage (tears) can occur. Replace as needed.

Scuba Tank

Scuba tanks for cylinders from shutterstock

Scuba tanks should be visually inspected each year and hydrostatically tested every one to seven years depending on local regulations. A tank that fails its visual inspection or hydro should be replaced.


A wetsuit is perhaps the most under-replaced piece of equipment. Most are only good for three years, five years max. Though a wetsuit may not appear damaged, looks can be deceiving. Neoprene compresses during every dive and, over time, loses its ability to insulate.

Other reasons to replace a wetsuit include: rips or tears, accumulated salt crystals, the suit no longer fits or it just plain stinks.

You’re Hanging on to Old Scuba Gear Too Long If:

  • The gear cannot be properly serviced.
  • Parts are so expensive the gear is costly to own.
  • It’s so dang heavy you pay overweight baggage fees every time you travel.
  • The gear no longer fits.
  • You’re ready for more advanced adventures but your beginner gear is too basic.

Don’t continue to dive with old gear for sentimental reasons or because it’s a sunk cost. If the gear is still usable, sell it and get something that meets your needs.

Learn more about how to inspect, clean, and maintain your dive gear in the PADI Equipment Specialist course . You’ll get hands-on experience from a PADI Professional and the certification counts towards Master Scuba Diver.

If you’re a gear geek, or just curious what the insides of your reg or tank valve look like, check out the PADI Equipment Specialist Touch for iPad or Android.




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