Info How to Choose a Regulator

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How to Choose a Regulator

(an overview of features and their value)

One of the first pieces of equipment that every diver will acquire is a set of Regulators. This is one of the most critical pieces of your gear as it enables you to breathe underwater and are considered to be life safety equipment. A challenge for many divers is there are a huge variety of options to choose from. Beyond taking the advice of your dive shop’s sales staff, how do you make an informed decision? Cost is one factor, but is expensive always better? How cheap is too cheap? What features matter the most?
The sales staff have a compelling argument that you should not be too thrifty when purchasing your “life safety equipment.” This article will attempt to give you some more information about the different regulator designs and features you will encounter, and why those features may or may not have value. I won’t suggest specific brands or models except as examples of the different designs. After you read this article, I hope that you will be better informed about your options and can make an informed choice the next time you need to buy or replace your regulators.

What does a Regulator do?​

A Scuba Regulator delivers air to the diver while underwater and allows them to breathe. What is happening in these devices to make that possible? Let’s break down the components to highlight the requirements of a SCUBA (Self Contained Underwater Breather Apparatus) regulator system.
  • A scuba tank is a cylinder filled with compressed gas at far higher pressures than the 15 PSI (1 BAR) you breathe at sea level. A typical scuba tank will be filled to a pressure of between 2400 – 3500 PSI (165-240 BAR)
  • A 1st stage regulator connects directly to the tank, and its job is to reduce the pressure it contains down to approximately 135 PSI (9 bar) required to operate your 2nd stage regulator. It must dynamically adjust as the tank pressure drops from over 3000 PSI (200 BAR) all the down to just 200 PSI (14 BAR) or less. Once the tank pressure is below 100 PSI (6 BAR) it will be increasingly difficult to breathe, and maybe impossible unless you are near the surface.
  • A 2nd stage regulator connects to the 1st stage and delivers air directly to the diver. The 2nd stage input is at the ~135 PSI (9 bar) delivered by the 1st stage. It needs to further adjust the pressure of the air delivered to the dive to match the “ambient pressure” of the diver. At the surface this will be 15 PSI (1 BAR) and at 100 feet deep this will be 60 PSI (4 BAR), or 4 X sea level pressure. (100 ft / 33 ft) +1 ATM
Regulators need to provide breathing gas at a pressure that exactly and continuously matches the water pressure at your depth. At 100 feet you will have 60 PSI (4 BAR) of pressure squeezing on your chest and lungs. If you had a 100-foot-long snorkel you would not be able to breathe from it as your chest would be crushed and unable to pull in the air. If a regulator delivers more than the ambient pressure, then you would blow up like a puffer fish. Not good. The regulators must be precisely designed and tuned to deliver exactly the right pressure.

Full Regulator System​

A complete regulator system for standard open circuit recreational scuba diving consists of five essential components.
  • 1st stage regulator
  • Primary 2nd stage regulator
  • Backup 2nd stage regulator
  • Submersible pressure gauge
  • Hoses for the SPG, 2nd stages, and BCD/Drysuit
IMG_20220227_152525.jpg

What Features are Important and Worth Paying Extra?​

There are so many brands with such a wide spread of prices. It can be confusing to know what brand is best and how much should you spend. Within a single brand there can be a spread of prices from hundreds to thousands of dollars.
The reality is that pretty much every regulator being sold by a legitimate dive shop is going to be safe and reliable for standard recreational diving. The most expensive regulator is not going to keep you more alive than the cheapest one. It also may not be more reliable than the cheapest one. It might even be the case that the cheaper one will be more reliable over time than the expensive one.
The same is true with brands. Very often dive shops will have a relationship with a particular brand and might sell that brand more than another, and they probably don’t offer more than one or two of the top selling brands. In general, one brand is not better than another. Most brands have a range of models that vary from basic to fancy. As you scale up in price you get added features. Some are useful, some merely cosmetic, and some that aren’t valuable to everyone. We will cover different options and features in the next section, and I’ll call out some of the more important and useful features that you should look out for.

Serviceability is the #1 Feature 👍

The only comment I will make about Brands in this article relates to serviceability of your regulators. Every single regulator from the least expensive to the most expensive will eventually need to be serviced. After one or two years of use your regulators need to be serviced. If you skip service for a year or two longer you might get away with it for a while. But eventually every regulator will fail and need service. Most brands & models have a 1-3 year recommended service interval. Get your regulators serviced before they fail and start to have problems.
A 1st stage regulator is typically made of a solid chunk of chromed brass and filled with stainless steel springs, synthetic or rubber o-rings, seats, diaphragms, and other plastic parts. Eventually the o-rings will wear out, lubrication needs to be reapplied, and corrosion or grit will build up until the regulator starts to have issues. A regulator needing service might leak, the Intermediate Pressure might no longer be to spec, or could even dramatically blow a seal.
The one feature that you absolutely need to prioritize is: Can I get this regulator serviced, not just from the shop you bought it from, but you get it serviced anywhere in the world?
For most of the top brands of scuba gear, the answer to this question will be Yes. Brands like ScubaPro, Aqualung, Apeks, Atomic, Mares, Poseidon, Oceanic, etc. have parts and service centers all over the world. There are other good brands that might only be serviceable in North America or Europe. Any of these might be great options. Just make sure that you understand how to get your gear serviced wherever you live.
I strongly recommend that you avoid any brands that don’t have widely available service. I’ve seen many divers using regulators I could not identify. There are plenty of cheap regulators available online that are from unknown brands. Many of them are clones of more popular brands or model, and they might work just fine. But eventually they will need service, and if you can’t find a convenient shop to service them you will likely need to buy brand new gear. When a regulator needs service, you need to buy a “Service Kit” from the maker of the regulator. The kit consists of a complete set of o-rings, diaphragms, seats, and seals that experience wear in the regulator. Sometimes other parts break or wear out that are not part of the service kit. If your Brand can’t supply service kits and replacement parts, then no dive shop or service technician is going to touch it.

IMG_20220227_165825.jpg


Continued in the next post

 
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Continued from previous post



How to Choose a Regulator (continued)​


1st Stage Regulator Features​

As mentioned earlier, every regulator sold by a reputable dive shop is going to get the job done on a basic recreational dive. There are a wide array of designs and features that you will find in various regulators. Some of these are very desirable, some are just useful and nice to have, and some are absolutely required but only for a minority of divers. Let’s cover some of the common designs and features.

Ports and Turrets 🤔

The most basic and inexpensive 1st Stage regulators will have the bare minimum number of ports. The cheapest regulators I’ve seen have just 1 HP port and 2 LP ports. These regulators are only useful on a pony bottle for bailout. A more common arrangement is a single HP port for a pressure gauge, and 3 or 4 LP ports for two 2nd stages, a BC inflator, and Dry suit inflator. As you move up to mid-range regulators you can expect to find 2 HP ports. This allows for a traditional SPG as well as a wireless pressure transmitter, or two wireless transmitters.

Another useful but merely nice to have feature is a rotating turret for the LP ports. Some divers prefer to have a turret as they may enable cleaner and more accessible hose routing on their systems. When diving sidemount or using slung stage bottles this more complex hose routing can be a must have feature.

Finally, there are a few regulators that have what is often called a 5th port. The ScubaPro Mk25 and its Halcon equivalent have both a turret with 4 LP port plus a 5th port on the bottom on the turret pointing straight down. Divers using a Double Tank configuration often prefer this 5th port feature.

Doubles.png



Most divers will be well served by any 1st stage with 1 HP port and 4 LP ports. But as you can see there are many scenarios where more and more flexible port positioning will make your life easier and give you room to grow and adapt your diving style over time. Be sure to avoid regulators with only 3 LP ports if you plan to dive with a dry suit!

Piston vs Diaphragm 🤔

All first stage regulators fall in to two basic design patterns, Piston, or Diaphragm. Pictured here are two popular regulators of each design. The Apeks DST (left) and the internal diaphragm it uses below. The ScubaPro Mk25 (right) and its internal piston below.

The piston and diaphragm designs refer to the primary moving part in each regulator that transmits the ambient pressure of the water outside the regulator to the mechanical parts inside that set and balance the intermediate pressure output to the 2nd stage. Both regulators pictured here are excellent units and have very similar feature sets. They both have 2 HP ports, 4 or 5 LP ports, and a rotating turret for the LP ports.

IMG_20220227_172111.jpg


Attributes of Piston regulators:

  • Fewer moving parts than diaphragms
  • Very high reliability
  • Service and kits may cost less
  • Ambient chamber with Piston, o-rings, spring open to seawater and sand
  • Requires good rinsing and soaking to clean out chamber after each dive
  • Can experience more wear and tear to metal parts if not carefully cleaned, limiting lifespan
  • Not as resistant to icing and freezing in water below 50F (10C)
Attributes of Diaphragm regulators:

  • Diaphragm completely separates water, salt, sand from moving parts
  • Often fully environmentally sealed from water and sand reducing wear on metal parts
  • Rinsing and cleaning is easier and less critical as the interior is sealed
  • Ideal for diving in very cold temperatures below 40F (4.4C)
  • Higher parts count and complexity than piston designs
  • Service and kits may be more expensive
  • Very important to service on schedule before the diaphragm wear out


As you can see there are pros and cons to each design. If well cared for, especially rinsing and cleaning after diving, both designs are an excellent choice. A diaphragm regulator might be a better choice for frequent shore divers working in very sandy and silty conditions, or those who often dive in below freezing temperatures as they are more resilient in these environments.



Balanced 1st Stage 👍

One very useful and desirable feature for 1st and 2nd stage regulators is addition of a “Balanced” design. A balanced 1st stage is particularly useful and can make a significant improvement in the ease of breathing throughout the dive. As described earlier, the primary job of the 1st stage is to output a steady intermediate pressure to the 2nd stage of around 135 PSI (9 BAR). As you breathe down your tank from 3000 PSI (200 bar) to under 500 PSI (35 bar), the 1st stage will tend to drift away from 135 PSI (9 BAR). This will result in more difficulty in drawing air as your tank pressure gets lower. A balanced 1st stage will compensate for the dropping tank pressure and ensure that the IP remains very consistent with both a full tank and a near empty one.

balanced 1st.png


Lower cost piston 1st stages tend to be unbalanced, while nearly all diaphragm designs are balanced.

There is a place for a very simple unbalanced piston regulator like the ScubaPro Mk2. The working part of the regulator is literally just the Piston, Spring, 2 o-rings, and a seat. You could no doubt hammer nails with it and then take it for a dive. When it is time for service you replace a couple of o-rings and the rubber seat. It can take a lot of abuse and is often used as a rental regulator. It may not breathe as well as a higher end balanced regulator, but it likely to live forever with minimal care.

That said, it is well worth paying a little bit more for a Balanced 1st stage.



DIN Connector 👍

Scuba tank valves are available with two different mounting adapters for a 1st stage regulator. The more traditional yoke adapter is more common around the world. The DIN adapter is not as common but has some real advantages over the yoke design.

IMG_20220228_110911.jpg


The traditional yoke connector is designed to connect to a standard 3000 PSI (200 BAR) valve commonly found on aluminum 80 CF (11 liter) tanks. The yoke fitting itself does not have an external o-ring that needs to be maintained. Conversely every tank has its own o-ring that is exposed to the elements. I expect most divers are familiar with the crusty cracked o-rings bubbling away on Caribbean dive boats.

The DIN connector uses a threaded, rotating fitting that is a much stronger connection capable of supporting higher pressure tanks. The tank valve does not have an o-ring, instead the sealing o-ring is on the DIN fitting itself. There are several advantages of the DIN adapter over Yoke. DIN is designed to support higher tank pressures than yoke of up to 3500 PSI (240 BAR). It is also more compact than the yoke and does not have screw knob on the back of the valve, removing a possible entanglement point.

I recommend a DIN fitting on 1st stage regulators for most Pacific Northwest divers. PNW divers tend to favor high pressure steel tanks over aluminum 80s (11 liter). Steel tanks negative buoyancy characteristics make them a better fit with dry suit diving, and at 3500 PSI (240 BAR) you will get a longer bottom time. Many modern tank valves have a removable plug that will convert between yoke and DIN. You can also easily add a Yoke adapter to a DIN fitting if needed. This will allow you to mount your DIN regulator on a tank with a Yoke valve.

IMG_20220228_111207.jpg

Titanium or Steel 1st Stage Body 👎

Most 1st Stage regulator bodies are made from chromed brass. One of the most expensive options available in a 1st stage is the titanium regulator body. Titanium is much lighter than brass and can reduce the weight of the regulator by about 1/3. However, that might only amount to 6 ounces (170g) of weight saved. A titanium regulator will likely cost about $1000 USD more than an identical chromed brass regulator. Besides the added cost, a disadvantage of titanium is that it cannot be used with a gas mixture of more than 40% O2.

Another variation sometimes offered is 1st stage body made of stainless steel or another “special” high end steel alloy. It’s not at all clear what benefit this offers over brass. They don’t weight less, and brass is more corrosion resistant than stainless steel. Steel and Titanium are also more easily damaged than brass.

Given the minimal weight saved and nice to have benefits, high end metal upgrades are purely a luxury option.


Continued in the next post

 
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davehicks

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Continued from previous post



How to Choose a Regulator (continued)​

2nd Stage Regulator Features​

Avoid Mismatched 2nd Stages (or don’t buy a cheap octopus) 👍

While there are variations on the basic recreational diver regulator setup, the standard configuration has a 1st stage paired with two 2nd stages. It is common to have different models of 2nd stages on the rig. A high quality (and priced) primary 2nd stage and a cheaper 2nd stage. This might seem like it has cost advantages when you are starting out, but I advise against this configuration.

In the long run you are better off with two identical 2nd stages. These don’t have to be the most expensive models, but you want both regulators to be of equal and acceptable quality for every dive. While you may use your primary the most often, when you need the backup 2nd stage you want it to be just as good. If you have an out of air incident you don’t want share an inferior regulator to your buddy, or have them give one to you. If it’s not good enough to be your primary regulator it should not be considered good enough for a backup either.

Beyond the emergency use of a 2nd stage regulator, you might also need to swap regulators due to a failure or need for service. When the regulators are serviced, it is convenient if they are identical and don’t need different service kits. If you end up learning to do your own service in the future, you can stock up on just a single service kit.

It is NOT necessary to have the same brand 1st and 2nd stage regulators. However, the full set does need to be tuned up as a complete unit. The 2nd stages need to be tuned to the proper sensitivity, also called “cracking pressure”, that is aligned with the Intermediate Pressure (IP) output by the 1st stage. A well-tuned 2nd stage moved from its paired 1st Stage to another 1st Stage might hiss, bubble, or be harder to breathe from due to IP changes. This is why it is important to tune the full set together.

BC Power Inflator / 2nd Stage Combo 👎👎💩

Another option that seems to be a favorite of Dive Shop package deals is the Inflator / Octo combo regulator. This odd duck combines two pieces of critical dive safety gear into one complicated and failure prone product. The first strike against the combo regulator is that it violates the no mismatched regulator rule above.

Screenshot 2022-03-04 125412.png


But it gets a lot worse! Buying one of these leads to a cascade of compromises and future problems.

  • If the 2nd stage starts to leak, bubble or hiss, you cannot just remove it or borrow another regulator because you also lose the BC power inflator. You would actually need to buy and carry around two of these turkeys to have redundancy.
  • You also can’t simply install a standard $15 power inflator on the BC because the inflation/exhaust hose that connects the BC to the combo regulator is proprietary and won’t fit.
  • The combo regulator requires a non-standard low-pressure inflation hose because the standard shrader valve LP hose does not pass enough air volume to operate a regulator. If you needed to switch to another BC you would also need to remove the non-standard high flow inflation hose and switch to a standard hose, assuming you had one.
  • You would also have to add an additional hose to your 1st stage to add a traditional 2nd stage regulator.
In short, if this combo regulator starts to have issues, you need to replace your BC, 2nd stage regulator, the LP inflation hose, and add a hose for the new 2nd stage. This is a ridiculous number of comprises to swallow in order to use an inferior octopus regulator.

Balanced 2nd Stage 👍

As with 1st stages, you can find both balanced and unbalanced 2nd stage regulators. The balanced designs are bit more internally complex in exchange for having easier work of breathing. They will compensate changes in intermediate pressure from the 1st stage as the tank empties during the dive. If your 1st stage is balanced, then the benefit of a balanced 2nd stage is likely reduced. However, an unbalanced 1st paired with an unbalanced 2nd stage is going to breathe a lot rougher than a balanced pair.

Your best experience will come from a balanced 1st stage pair with a balanced 2nd.

Adjustment Knob 🤔

Some balanced 2nd stage regulators feature an Adjustment Knob. This knob allows the diver to make very subtle adjustments to the cracking pressure of the regulator, which will slightly increase the work of breathing while make the regulator less likely to free flow. This can be useful especially on an octopus 2nd stage or a bailout bottle 2nd. If the regulator has a tendency to free flow or bubble a bit, tightening the knob can reduce this tendency.

Pictured are a non-adjustable ScubaPro R190 2nd (left) and an adjustable ScubaPro S600 2nd.

IMG_20220228_111621.jpg


A well-tuned 2nd stage regulator will be adjusted for just the right cracking pressure with the knob (if it has one) fully screwed out. It should breathe smoothly and not free flow too easily. If after a year or so you find, the regulator is starting to hiss or bubble you can tighten down the adjustment knob to counteract the unwanted air flow. However, this is a sign that the regulator is overdue for service.

An adjustment knob is not at all necessary on a well-tuned regulator, but it is a nice to have feature that may allow for a little more flexibility.

Titanium Air Barrel 👎

Titanium has found its way into 2nd stage regulator design as an expensive upsell feature. Unlike with 1st stages where it might save around 6 ounces (170g) of weight, on a 2nd stage the weight savings are likely to be miniscule. All 2nd stages have a fat straw-like “air barrel” in them that is typically made of plastic or stainless steel. Replacing this with titanium will make the regulator a tiny bit lighter than steel but not plastic. Titanium will corrode less the steel, but not plastic. It does not make any improvement to the breathing performance of the regulator.

Titanium remains a luxury feature. If you expect to dive the same regulator for 5,000 dives it may outlast its rival materials.

Final Thoughts​

Buying Used & Online Gear 🤔

I don’t recommend that brand new scuba divers buy used gear. Without more experience and knowledge, it is too easy to get misleading advice (irony intended) and become overwhelmed by the variety of brands, features, and unknown condition of what you are buying. You might be well assisted by a reputable dive shop and a knowledgeable friend but be careful when you are starting out. I promise that as a new diver there is more that you don’t know than you might think.

The same goes for buying gear online. As a new diver you really need to build up experience and learn from others. A local dive shop is a very valuable way to get advice and suggestions, and to connect with diving opportunities and new buddies. Sure, the dive shop wants to make money by selling your gear. It’s your job to ask questions and get more options than just whatever package might be on sale. Ask your fellow divers in the dive club about what gear they have found to be both high quality and good value as you make your spending decisions.

For more experienced divers however, used regulators can be a great option. There is a lot of lightly used gear available for sale and very reasonable prices. If a set of regulators is not banged up and abused, it can be used safely for decades. There are plenty of divers out there who have done many thousands of dives on regulators that were new in the 1970’s. Several models of regulators in production since the 1960’s are still fully supported with parts and service kits today. Since most of the moving parts susceptible to wear get replaced every year or two during service, a regulator can last for decades if well maintained.

If you do decide to buy a used regulator, be sure to factor in the cost of service. You will definitely need to have a used regulator serviced upon purchase. Factor in at least $50 USD per stage as an added cost. If you are not saving at least $100 USD over the cost of a new item, it’s probably not worth the trouble.




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davehicks

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This is an article that I wrote for my local Seattle based dive club newsletter. It's an overview of regulator features and attributes, describing what they are and what value they offer. It's all my opinion of course and my perspective is limited to my experience and reading. I'd love to know what features I might have left out, what features you value most, and if I am full of BS on any points covered. :)
 

rhwestfall

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You can also easily add a Yoke adapter to a DIN fitting if needed. This will allow you to mount your DIN regulator on a tank with a Yoke valve.
Expand with the statement that this is really an "emergency" configuration as many find it moves the first stage away from the valve further, frequently then causing the dreaded "head bang"...
 

Bob DBF

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However, an unbalanced 1st paired with an unbalanced 2nd stage is going to breathe a lot rougher than a balanced pair.

If tuned properly, there isn't as much of a difference that is advertised by those that don't use them, a novice will not notice any difference. What will happen is that the reg will breathe harder as you run out of gas which is a plus if one isn't paying attention.
 

James79

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Very important to service on schedule before the diaphragm wear out
I haven't heard of a diaphragm 1st "wearing out" the diaphragm in any vaguely reasonable amount of time (and I'm aware of at least one that was intentionally dived for 3 decades without service, and own one that hasn't been rebuilt for at least 35 years based on the second stage when I got it). It's fair to say any regulator should be serviced prior to parts wearing out, but it seems to me that the specific line I quoted is unnecessary/reads as a negative that isn't warranted.

Respectfully,

James
 
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davehicks

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I haven't heard of a diaphragm 1st "wearing out" the diaphragm in any vaguely reasonable amount of time (and I'm aware of at least one that was intentionally dived for 3 decades without service, and own one that hasn't been rebuilt for at least 35 years based on the second stage when I got it). It's fair to say any regulator should be serviced prior to parts wearing out, but it seems to me that the specific line I quoted is unnecessary/reads as a negative that isn't warranted.

Respectfully,

James
I have seen some sorry looking diaphragms in regs i have serviced, and seen a couple fail in use and start bubbling away.

I should probably amend this to reference the hp seat too as the seat is a significant point of wear and failure.
 

rhwestfall

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Sorry if this is not where you wanted to go, but you should write a section of basic monitoring..... In my 30+ years, I've learned mostly that 1-2 year service is unnecessary, and can lead to damage... you service when it needs it. There are signs when it is heading toward need...
 
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