How to pick your first rebreather
The topic of choosing one’s first rebreather is always an interesting and challenging one. It’s a controversial topic to say the least. Rebreather divers and instructors have great enthusiasm for the product they own or instruct on. The debates that rage on about which rebreather is ‘the best’ sometimes have the passion of a political or religious argument. I am no different in this regard.
I’ve been involved with rebreathers professionally for 13 years. I was lucky enough to work for a dive shop whose owner was an early adopter of rebreather diving. It was 2006 in Pompano Beach, Florida, where I was first exposed to the technology, and then soon after was certified to dive one, and purchased my first unit.
To be very clear, this article is not about my views on which rebreather you should buy. It is however, about how you should approach the process of choosing one.
It’s a question I get a lot. Over the years, I’ve owned 5 different rebreathers, and have been lucky enough to become certified on 7 of them, and dived 12 different rebreather sets under the supervision of an instructor. More than that, I’ve helped thousands of rebreather divers in sales, support, maintenance and troubleshooting, both in-person and online. I’ve assisted hundreds of rebreather classes at all levels, at one point across a product line of a dozen different manufacturers. I’ve learned a tremendous amount in this time. I’ve seen things that work, and things that haven’t. If I could do it all over again, there are probably a few things I would have done differently.
In that regard, here is the best advice I can give those who wish to go down the rebreather journey, but are unsure how to proceed.
1. Understand, there is no perfect rebreather
If you’re looking for the Shangri-La of rebreathers, you can stop now. All of them have their pros and cons. Accept that whatever decision you make will be a compromise in some way. If you hear someone tell you their rebreather is perfect, they are lying or mis-informed.
It’s likely you’ve heard this before on a Facebook group or internet chat forum. And it’s true. Much like choosing an automobile, there are different features, different options, different ways of doing something, and even different cosmetic points that all appeal to different diving needs and different personalities.
2. Learn rebreather basics first
Before you go any further, get a good, solid understanding of rebreather fundamentals. Learn the basic components of a rebreather, what they do, and how they work. Most importantly, learn that there are different options, and familiarize yourself with the differences. Such as:
BOV vs DSV. What is a BOV and why would I want one? Why would I not want one?
Back mount vs chest mount counterlungs?
Radial vs Axial scrubbers. What’s the difference?
Electronic vs mechanical rebreathers. Huh?
Do I need a CO2 sensor?
What does a temp stick do?
What does 'work of breathing' mean?
What's the difference between hydrostatic work of breathing and resistive work of breathing? Does it matter?
How does one learn about these things? I’d start off with a few books:
Mastering Rebreathers by Jeff Boznic There’s 2 versions of this book, be sure to get the 2nd edition, as this is more current. The previous version, also called Understanding Rebreathers, is written in 2002 and a bit out of date.
The Basics of Rebreather Diving by Jill Heinerth
Rebreathers Simplified by Mel Clark.
While dated, (the most recent book was written in 2013,) these books will lay the groundwork for rebreather basics, and help you know what questions to ask. Learn what the acronyms mean, (what is an ADV?) learn what the components are, and what they do and how it ties in together. If you have the occasion, visit a local dive show and see the rebreathers firsthand. Get someone to take it apart and walk you through it.
Be sure to browse some of the videos on YouTube. Divetech has a YouTube channel where we feature several videos on rebreather diving, and there are hundreds more out there.
3. Ask lots of people
Of course, as part of any basic research, you ask the opinions of others.
But you should approach this topic with a bit of caution and an open mind. Remember that every single person you will speak with has some sort of bias to one degree or another.
Many rebreather divers are males in their late 50’s to mid 60’s. Retired or semi-retired, they are often business types who did well enough in life to be able to afford such luxuries. Many have strong personalities, and it’s hard for some of them to admit that the $10,000 purchase they made was not the correct one.
Rebreather instructors may also be this type, but in addition, have invested a lot of money and time in a career path that focused them on one or 2 brands. Jumping to another unit might be difficult at this stage. For them, they have a financial interest in promoting a certain rebreather, even if it's not the best.
Mostly what you will encounter, are divers who simply don’t know what they don’t know. They may not have seen very many rebreathers, any don’t know that another method or style even exists. You may even find instructors like this. I once heard a rebreather diver say “Nothing breaths as good as a meg.” I asked him, "What other units have you tried?" And he replied "None!" It’s hard to say nothing tastes better than a Pepsi, if you’ve never tried a Coke.
My advice is to learn as much as you can, from as many people as you can. Of course ask people what they like about their rebreather, but also be sure to ask what they don’t like. Be sure to find contrasting opinions. For example, if you find someone who is a fanatic about radial scrubbers, be sure to find someone else equally passionate about axial scrubbers. Learn both sides of every feature, so you can make your own, informed opinion.
Seek out, and find those who have 10-15 years of experience in rebreathers. Often these are the ones who have owned multiple units, and have learned from their own mistakes. They will discuss the pros and cons of their rebreathers with a more open mind, than someone who is at the peak of the Dunning-Kruger effect.
Here's a good question to ask any rebreather fanatic: “If the brand you dive never existed, what would you dive?”
4. Most of what you read on the internet is wrong
Fans of Cold-War era spy biographies may have heard of the term "Wilderness of Mirrors." It was a rather effective ploy by the Soviet KGB to spread mass amounts of disinformation to the American CIA, in an effort to undermine their intelligence gathering. It was combated by American and British intelligence analysts with the careful application of scrutiny, critical thinking, and pattern recognition.
There's no shortage of disinformation on the internet. While unlike my cold war analogy, I don't believe (most of) this disinformation is deliberate, it is no doubt out there. During research for this blog, I found hundreds of articles that rank 'the best rebreathers of 2019' and many other similar topics. Some of these articles are mildly accurate, and some are downright wrong. For many I read, it seems the authors have likely never seen a rebreather, or if they have, their experience may have been limited to a try dive, or at most a recent certification class. The topic of rebreathers is a hot-button one, and can surely draw attention to a website or blog, which is why many chose to write about it - regardless if they know what they are talking about or not.
The internet has no peer review process. Anyone can post a blog or an article and claim it as credible. Even this blog you are reading now. Use this same combination of scrutiny and critical thinking to filter the wheat from the chaff of your rebreather research.
5. Do not get a brand just because it’s what everyone else dives
I hear this a lot. Rebreather divers visiting us will say “I bought this one because that’s what my friend dives.” As the saying goes, "if your friend jumped off the bridge, would you jump too?"
Many divers feel comfort in knowing they can get support, spare parts, or just tips and tricks from divers in their local circle. There is something to be said for a local support system - sometimes. Be aware however, just because your friends are rebreather certified, doesn’t mean they know how to service and repair the units they dive, or even know what they are talking about. SubGravity owner and TDI Instructor Trainer Randy Thornton just posted a blog article called “Don’t Trust Your Friends,” which discusses, among other things, all of the bad and sometimes harmful advice he’s heard disseminated by ‘the local experts’ over the years.
Any good CCR instructor will be reasonably available by phone, email, or video call. My past students know they always can (and do) call or message me with questions or problems for as long as I am alive, and have my wits about me. A good rebreather manufacturer will offer the same support. From firsthand experience, I know the owners of KISS, Sub Gravity, rEvo, Dive Rite, and Innerspace Systems Corp, (and many others) will answer private messages at all hours of the day and night to help their customers through various issues. In today's day and age, professional support is readily available to you, and with expedited shipping, this largely negates the need for the local assistance.
6. Do proper try dives
A try dive is where one conducts a CCR dive with an instructor in a pool or other shallow body of water. In my experience, there are generally 2 types of try dives:
The first type is the mass-try dive. This is where an instructor or group of instructors will have rebreathers at a pool for prospective students to strap on and swim around with. I'll apologize to my instructor friends who I see conduct a lot of these, but sadly these types of try-dives are next to useless. It is analogous to the following scenario: Let’s say you were considering buying a Porsche. You go to the Porsche dealership and ask the salesman to test drive one. He or she says “Of course! You may back it out of the parking spot, but please don't adjust the seat or mirrors.” This of course is not representative of the experience of driving a Porsche. It certainly isn’t representative of the experience of owning, servicing and maintaining one either.
Pool-only try-dives are very limited in their scope. The pool is a very difficult environment to dive in. Even experienced CCR divers have a tough time in the shallow confines of a pool. Buoyancy is hard, the harness is often not sized correctly for the individual, and counterlung placement often isn’t optimal. Your trim and weighing will be off, your time on the rebreather is limited, and you simply lack the knowledge to know what is occurring with the unit on your back. Likely, you will not have the chance to prepare, assemble, disassemble and clean the unit. You’ll very likely not have the opportunity to troubleshoot potential problems of the unit. (This is part of rebreather ownership!) Many instructors like conducting try-dives, as it is a great opportunity to generate sales leads, and bond with a prospective client.
The second type of try-dive is sometimes known as a Rebreather Experience (IANTD,) or Discover Rebreather session (TDI.) These can be somewhat informative, as they are a bit more comprehensive. At Divetech, we run them one-on-one mostly, although sometimes we will have up to 2 students. They are half day experiences, which go through assembly, disassembly, maintenance, as well as a dive along our house reef.
Open water try-dives can provide a better learning experience, but take these with a grain of salt. It’s a lot of information crammed into a short amount of time, and you'll often forget most of it.
7. Learn about the manufacturer
Do some research on the manufacturer of the rebreather, and find out (in order of importance:)
1. Do they engage in 3rd party testing? They should, and this is how you will differentiate a reputable rebreather manufacturer from a hobbyist who happens to own a machine tool in his shed.
While rebreathers as a concept are pretty straightforward, as you begin to design them, the intricacies of flow dynamics, scrubber bed movement, and hydrostatic imbalances begin to raise their ugly heads. It turns out building a rebreather isn't as simple as we thought. Any reputable manufacturer will have their product tested for a number of parameters to make sure the product is safe for use.
2. What kind of service and support do they have? A rebreather is a mechanical device and any mechanical device will fail at some point, regardless of who made it, or how tough they say it is.
Some rebreathers are more prone to failure than others. Many of these are operator errors. I can tell you with absolute certainty, that every failure I've ever had was the result of my own impatience and stupidity. Most types of failures can be mitigated with proper preventative maintenance. Here are a few thoughts:
How hard is it to do the maintenance and service?
Can you do the service yourself, or does it need to be sent somewhere?
Can you buy parts yourself?
Do you even want to do it yourself, or do you prefer someone work on it for you?
If you cannot, or don't wish to do the service, where is the nearest service center?
Is this a factory authorized service center? Or someone not authorized to make repairs?
Will it be easy for you to ship broken parts to them? Do you have to ship the entire unit?
What sort of reputation do they have? Some service centers are the model of efficiency and customer service. Others make dealing with your cable provider’s call center seem like pleasure.
3. How solid is the rebreather company? In 2007, a rebreather startup company took $1,500 deposits from many customers. They eventually delivered only a handful of units, none of which ever functioned as advertised. The company later filed for bankruptcy, leaving those who paid good money, out of luck. In 2011, a US-based manufacturer made very aggressive efforts to promote their amazing new unit, only to go out of business 3 years later, leaving no source for parts or support. In 2016 a third manufacturer left hundreds of their customers high and dry with a unit that had an abysmally high failure rate. They stopped supporting the unit when the company was sold a year later, leaving those who owned one of these rebreathers with an expensive halloween costume.
I'd like to leave you with the following statements:
I began by saying there is no perfect rebreather. Understand there is no unsafe rebreather either. Any modern rebreather made by a reputable manufacturer has undergone 3rd party testing, and is safe for the user, provided you diligen