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- What To Consider When Choosing A Rebreather
- Best Rebreathers
- Should I Buy A Rebreather?
- Frequently Asked Questions
Although they were the first machines you could use to venture below the surface, rebreathers are still misunderstood by many recreational and technical divers.
But we think they are the future.
As technology is getting better, rebreathers are getting smaller, more reliable, and more affordable.
Nonetheless, buying your own closed-circuit rebreather (CCR) is still a significant investment.
And there are enough models on the market to make your head spin.
Rebreathers all share the same task; to save gas underwater. Rather than wasting exhaled gas into the blue, rebreathers recycle it, removing dangerous levels of CO2 and balancing the correct level of oxygen in the breathing loop.
It sounds simple. But how different models and manufacturers execute that task can make it hard to choose which CCR is best for you.
Once you’ve found the right rebreather, however, it will revolutionize your diving experience. And you’ll never want to go back to blowing bubbles again!
So let’s find you the best tool to enter a silent world.
What to consider when choosing a rebreather
Before we start, let’s run through some of the important components to look at when choosing a CCR:
- Counter lungs are flexible bags that allow gas to be stored around the unit. Depending on the position, they will affect the work of breathing.
- Scrubber duration and size will be the primary limiting factor of your dive time. Bigger scrubber equals longer dive time.
- Reliable electronics monitoring PPO2 and dive parameters are vital for a rebreather as these provide essential information and control the PPO2.
- Manual add valve allows you to control how much oxygen you are adding into the breathing loop while running it on or off board.
- Plugins offer you the possibility to plug in your off-board gas during the dive.
- Maintenance is much more complicated on CCR than open circuit regulators. Choosing a reliable, durable, and reasonably easy to maintain unit with affordable spare parts will save you some cash in the long run.
It’s also essential to ask yourself what type of diving you’ll use it for and will it satisfy your needs?
If you want to travel a lot with your rebreather then Triton will be your best option. Alternatively, if you want to do deep exploration dives then maybe consider buying a JJ-CCR.
Before making a final decision on what rebreather is best for you, you should try out a few different models.
The tech community calls the JJ-CCR ‘the 4 x 4 of the rebreathers’, which is the perfect description. It’s built to fit all environments and handle the most demanding adventures.
The philosophy behind the JJ-CCR is to keep it simple with robust construction and minimalistic work detail, making it easy to handle before, during, and after the dive.
Best For Expedition Diving
- Counter lung location: back and shoulder-mounted
- Work of breathing: Good. Unit should be dived slightly head up.
- Scrubber Size & duration: Axial as standard 2.5 kg and 3h*, radial as additional 3kg. 4h*
- Electronics: Shearwater Petrel 2 primary controller and LED HUD running on independent battery in a computer malfunction. Optional NERD in place of HUD. Deco algorithm Buhlmann ZHL-16C with gradient factors (can be unlocked with VPM-B).
- Maintenance: Easy. You can maintain the whole unit yourself apart from 1st stages, Solenoid & Electronics, which should be serviced at an authorized service centre worldwide.
Value for money: 5 / 5 stars
- Ready for deep trimix diving straight off the box.
- Well priced service kits and cells.
- Versatile, easy to add on additional wing inflator cylinders for deep dives.
- Simple design reduces failure points.
- Rugged and strong build, capable of withstanding rough handling
- Built-in redundancy provides necessary backup in case of malfunction without the clutter
- Bulky, diving in a current creates quite a drag.
- Heavy, not the best unit to travel.
Triton is a mechanical chest-mounted rebreather intended for all recreational and technical divers. It’s designed and developed in France by M3S, and it’s currently the lightest CCR on the market.
Best for: Traveling divers plus caves, wrecks, and dual rebreather diving.
- Counter lung location: At the front
- Work of breathing: Excellent. Dive in a horizontal position
- Scrubber size & duration: 2.1 kg and 3h*
- Electronics: Fitted as standard with a PpO2 control displaying HUD and Monox computer. As an option, the Petrel 2 computer or the NERD 2 from Shearwater can be integrated (Deco algorithm Buhlmann ZHL-16C with gradient factors, can be unlocked with VPM-B).
- Maintenance: Easy, due to lack of complex electronics inside the unit.
Value for money: 3 / 5 stars
- Compact, efficient, and easy to travel with.
- You can combine it with any BCD style, from recreational wing to side mount.
- Lightweight, it’s 12.2kg ready to dive, and only 7Kg when packed for travel.
- Very reactive to flushes and O2 injections.
- Manual rebreathers can be task loading during an emergency on the ascent.
- Cell connection is not as reliable as in other units, which can affect your PpO2 reading underwater.
- Sound alarm on the Monox computer can’t be switched off during the dive
- HUD and Monox work from the same battery; therefore, you lose both in case of computer malfunctions.
Embracing technological innovation has led Poseidon to create an intuitive rebreather that’s easy enough for any diver.
Depending on the package, Poseidon SE7EN is an excellent tool for recreational and technical divers wishing to explore the silent world.
Best for: Photographers and researchers as the controller allows them to direct attention to their task at hand.
- Counter lung location: Back-mounted
- Work of breathing: Good. Dive in a horizontal position.
- Scrubber size & duration: 2.4kg 3h*
- Electronics: Design by Poseidon comes with M28 dive computer with dual deco algorithm, DCAP, and Buhlmann ZHL-16C. Gradient factors are adjustable only on the surface.
- Maintenance: overcomplicated, can be time-consuming, but most parts are easily interchangeable.
Value for money: 2 / 5 stars
- Very appealing and futuristic design
BOV can be easily switched in the event of needing a bailout.
- The unit is equipped with vibration, visual and audial alarms which alert the diver to any problems.
- Large number of fail-safes, that if working correctly, significantly reduce the likelihood of human error.
- Diluent solenoids will regularly fire to monitor and cross-check readings of the O2 cells.
- Slow to assemble and disassemble.
- Electronics modules can only be serviced in Sweden.
- With unit in-built alarms, there is a risk that divers may become complacent.
- Some alarms will continue even if the problems have been solved by a diver underwater.
- Requires many additional purchases to make the unit suitable for technical diving.
- Quite challenging to achieve perfect trim.
SF2 is configured to be streamlined and simple. It’s a well-arranged unit where all crucial components are integrated into the carbon fiber tube. Therefore, the SF2 takes up significantly less volume in the water column than other rebreathers. It’s also available as either a back mount or a side-mount rebreather.
Best for: Ambitious technical dives suited for all types of environment.
- Counter lung location: Inside a carbon fiber tube, below the scrubber canister on divers back
- Work of breathing: Good. dive in a horizontal position
- Scrubber size & duration: 2.2 kg duration 3h*
- Electronics: Shearwater Petrel2 and a fisher cable for the diver choice of a HUD, Petrel, or NERD as a backup. Deco algorithm Buhlmann ZHL-16C with gradient factors (can be unlocked with VPM-B).
- Maintenance: Easy; you can perform essential maintenance yourself. Advanced repairs, like electronics, must be done in a service center available worldwide.
Value for money: 4 / 5 stars
- Ready for deep trimix diving straight of the box
- Sidemount Conversion Kit allows you to switch the unit from backmount to side-mount.
- Absence of T-pieces in the loop connection reduces failure points.
- Well protected counterlung makes it the most efficient flood recovery on the market.
- Increased work of breathing (WOB) if out of trim position.
- Addons necessary to mount additional wing inflator tanks.
- Converting from backmount to sidemount takes a lot of time, experience, and configuration checks to get it right.
AP Diving has been designing reliable rebreathers for more than 50 years, making it one of the oldest CCR brands on the market. They had time to learn from their mistakes and it’s clear to see through the rebreathers they offer.
AP Inspiration EVP rebreather is a compact unit, making it nicely streamlined underwater. It comes with a large scrubber that allows for longer dives.
Best for: Skilled CCR divers looking for various dive profiles, from shallow reefs to wrecks and deep walls.
- Counter lung location: choice of over the shoulder and back-mounted
- Work of breathing: good in trim as well as in more vertical position
- Scrubber size & duration: 2.45kg duration 3h*. Fitting a temperature stick to the unit allows you to extend these times as the tempstik bases its readings on the scrubber’s actual work rate, temperature, and depth.
- Electronics: AP design electronics for their units. Decompression planning runs on Buhlmann ZHL-16C with gradient factors. Primary and a redundant controller as standard.
- Maintenance: Fairly Easy some parts are user-serviceable, but more considerable repairs need to be done by the manufacturer.
Value for money: 4 / 5 stars
- Solid, reliable unit that can withstand all dive conditions
- Lots of support available worldwide.
- No limits regarding diving depth with the trimix software
- Extremely flood-resistant.
- Well-researched, well-developed, and proven unit.
- “Yellow/Black box” design won’t appeal to everyone
- It’s inconvenient to return the unit to the manufacturer for some repairs.
- Diving in a wetsuit tends to make the unit bottom-heavy.
*Scrubber duration is determined by testing in extreme conditions using a breathing simulator with the maximum workload and a water temperature of 4 °C (39 °F).
Should I Buy A Rebreather?
A rebreather is a great choice for any diver ready to sacrifice the simplicity of open circuit to experience the silent world of diving.
It is an ideal tool for underwater photographers and videographers. Lack of bubbles allows you to have much closer encounters and great interactions with marine life.
Rebreathers are great for technical divers looking to extend their bottom faze of a deep dive and accelerate the decompression time.
They’re also excellent for marine scientists looking to prolong their dive time and no-decompression time limits while collecting samples.
Pros and Cons of rebreather diving
The advantages of diving on a closed circuit rebreather are enormous. But there are few disadvantages as well. Let’s have a look…
- Extremely gas efficient: perform deeper and longer dives with minimum cost (especially for those using trimix). Unlike open circuit regulators, depth has no impact on gas consumed by a diver.
- Accelerated decompression: Breathing the best mix at every depth makes decompression stops much shorter, allowing you to get out of the water faster.
- Optimized oxygen level gives you more time to enjoy the bottom faze of the dive, perfect for deep wrecks and cave exploration.
- Way more time on no-stop dives: It’s like having a nitrox blender on your back. Rebreathers are delivering the best oxygen mix at any stage of your dive, reducing the amount of nitrogen dissolving into the tissues, therefore extending your NDL’s
- Problem-solving: CCR gives you the ability to deal with the problem in many different ways, as well as giving you more time underwater to come up with the optimal solution.
- No bubbles: Rebreathers are silent, giving you the chance to truly become part of the ocean.
- Perfect buoyancy control as it’s not affected by your breathing
- Comfort: Rebreathers deliver warm moist air decreasing the risk of hypothermia and dehydration
- Expensive: Even though rebreathers are getting more popular, they’re still way beyond many recreational divers’ budget.
- Not for everyone: You need the right mindset and good discipline as a diver to understand the machine’s complexity and dive safely. There is no space for negligence or complacency as it’ll most probably be fatal.
- Maintenance is way more complicated than the open circuit regs. It’s your life support machine and needs to be treated with respect. If not taken care of properly, it will kill you.
- Monitoring instruments during the dive: Malfunctioning on CCR can be very subtle; therefore, you need to monitor your devices much more frequently.
- Emergency gas supply makes it quite bulky underwater. You always have to carry additional bailout cylinders, as an individual or within a team.
Frequently Asked Questions
How long can you dive with a rebreather?
The amount of time you can spend underwater with a rebreather depends on the model you are using and the scrubber duration. The bigger the tanks and the scrubber, the longer you can stay underwater.
However, you always need to carry an adequate amount of gas to safely bailout in case of rebreather failure.
Are rebreathers dangerous?
No, rebreathers themselves are not dangerous. Manufacturers spend years designing and developing their units.
Before they’re let out on the market, rebreathers undergo incredibly rigorous testing. They’re tested in harsh conditions by divers as well as machines specially designed for this purpose.
Make sure that the rebreather you choose has all the specifications in place.
The most significant danger in rebreather diving is the user. Most fatalities on CCR are caused by human error, not the apparatus itself. Remember to always follow the manufacturer’s recommendations and only dive within the limits of your training.
What are the potential risks when using a rebreather?
The products we’ve recommended above are some of the safest rebreathers on the market. Of course, just like with any dive gear, there are always risks if not used properly.
Hypoxia is one of the main risks in CCR diving.; This is why you need to frequently check your oxygen levels during the dive. Controllers built in a rebreather make it easier. But you should never trust them blindly.
Another potential hazard is general CCR malfunction on a dive. Therefore, you must carry adequate OC (open circuit) bailout on every CCR dive. With proper training and the right equipment, you can easily overcome all the possible problems and safely enjoy rebreather diving.
How can I buy a rebreather?
To buy a rebreather, you need to be a certified CCR diver. Some manufacturers will allow you to do it only through their approved dealer (instructor or a dive center) to ensure your safety. Diving rebreather is unit-specific. So it’s best to get certified on a specific CCR before you purchase it.
Every rebreather has its strengths and weaknesses. Which one is best will always depend on the situation you want to use it in.
Now that you have a bit more knowledge about choosing the best rebreather, we recommend you research and learn more about the specific unit that interests you.
No matter which rebreather you’ll choose, exploring the underwater realm will become much more exciting, as you become not just a visitor, but a part of the ocean.
Fish seek your protection and often use you as a shield from currents or predators. The interactions are just incredible. It is also a game-changer for deep exploration dives.
Already a rebreather diver? Tell us what was your most amazing underwater encounter while diving on CCR?
Laura, better known as ‘Kazi’, is a PADI Course Director, passionate tech diver, journalist, and brand ambassador living on the small island of Gili Trawangan, Indonesia. When she’s not training the next generation of divemasters and instructors, you’ll find Kazi on CCR dives exploring the deep walls of the Lombok Strait. Keep an eye on her adventures on her social media: