Best CCR in 2025-2030 Rebreather Markets

[Chris-Wood]

Please without asking me to stop asking the basic questions, if cave diving and dewatering are non-issue for a diver, does anyone know any reason to choose any other rebreather, other than the rEvo?

What makes you think the rEvo is the best rebreather?

 

[stuartv]

Reasons NOT to choose a Revo:
I don't buy into the "if 3 is good, 5 must be better" theory

My Choptima has 3 sensors. If they get wet (enough) or caustic on them, I can lose all of my ability to monitor my pO2. I have to go off the loop to complete my dive (or SCR mode, of course).

If the board that they are all connected to dies, I have to go off the loop (or SCR).

2-ish years ago, Dive Rite had a run of bad wiring harnesses for the O2 sensors in the Choptima that were not crimped properly or something (I don't remember exactly). It was not unusual to lose a sensor or maybe even 2 during a dive.

My rEvo has 5 sensors. 3 are connected via a DiveCAN board to my controller. 2 are connected via an analog cable to my NERD.

If I lose any 3 sensors, I still have a fully functional computer with actual pO2 monitoring I can use to end my dive on the loop (with valid deco calculations). This happened to me once when I flooded my unit during a dive (my error during the build). I dunked 2 of the sensors on my controller in caustic and they went out to lunch. The 2 on my NERD were still reading correctly, as was one on the controller. I watched all 3 to ensure that my NERD was calculating my deco correctly. Manual voting logic, if you will. I was able to finish my dive on the loop with no drama at all.

If the DiveCAN board that the sensors for my controller are connected to dies, my NERD (and its 2 sensors) still works perfectly fine. If ANYTHING happens to my controller, the DiveCAN bus, the cable to the sensors, or the 3 sensors on the controller, I still have my 2 sensors on my NERD, completely physically separate.

That may not equate to "better" to you. But it does, to me!

For all the talk I read from people advocating redundancy, it is pretty ironic how many people knock on the redundancy in pO2 monitoring that a rEvo offers. I mean, it's not just extra sensors going through the same DiveCAN bus as the 3 primary sensors. It is a completely, physically separate set of sensors and a monitor. It's not an official factory configuration, but you even CAN fit a 6th sensor in the tray and have 2 completely independent, isolated from each other, sets of 3 for 100% redundant sensors with full voting logic.

I definitely think it's better. I have benefited from having 5 in my rEvo. I have suffered the consequences of only having 3 (in my Choptima).

They are significantly negatively buoyant, and a challenge to dive in a wetsuit without adding additional weight for trim

I use 3L steels all the time. I am definitely over weighted when I dive in a 3mm wetsuit or a rash guard and shorts. It actually seems pretty close to correct weighting when I'm in a 5mm, but I digress.

I never add trim weight. The only time I add weight at all is if I'm in cold ocean water (i.e. drysuit and salt water). Then, I'll usually add a 4# soft weight between the dil cylinder and the middle of the scrubber. Or, if I'm in really cold fresh water. Even then, I can't remember the last time I added more than the one 4# soft weight.

In any case, I have no trouble holding good trim. The key (I think) is that my unit has a Dive Rite Nomad XT wing instead of the factory wing. It's a sidemount wing and it is shaped to distribute the lift more towards the diver's feet than a traditional back mount wing. And, full disclosure, my unit even has the factory rEvo (steel) stand on the bottom, adding to the weight at the bottom of the unit.

I say "I think" because I have or have had this type of wing on all my rEvos. I have never dived a rEvo with a factory wing - but I know it is pretty common for rEvo divers with factory wings to use a little trim weight on the top of the unit.

I guess you can knock the rEvo for needing an aftermarket wing in order to dive in trim. But, a lot of other units don't even come with a wing at all. I would only have an issue if a unit couldn't be made to facilitate good trim with ANY wing, and you had to use trim weight no matter what wing you used.

just because two people said the ability to dewater isn't that important, doesn't mean it isn't actually important. It just means the unit meet their needs enough that that particular problem isn't a primary concern.

Totally valid point.

I do like the dual scrubber idea though. And I did seriously consider going with one.

I agree. I think that is a very good feature.

I also think the rMS system for monitoring the scrubber is absolutely awesome. It used to be somewhat prone to failure (back 10+ years ago). In the last 6 years, and 3 different units I have experience with, every rMS part I have replaced (all my units were old and purchased used) is still working just fine.

 

[Mas.]

What makes you think the rEvo is the best rebreather?

I don't. In fact i am literally asking for help to find a reason not to choose the rEvo.

 

[Mas.]

just because two people said the ability to dewater isn't that important, doesn't mean it isn't actually important. It just means the unit meet their needs enough that that particular problem isn't a primary concern.

True. Do you think dewatering become less important for shallow dives in range around 0-50 meter?

 

[Mas.]

my shortlist for my first rebreather was Revo, JJ, X-box.
I chose the Revo as it has a double scrubber, uses less sodalime than others, fully redundant electronics (3+2 cells feeding two computers), it had few moving loop components (no T-pieces), has both an orifice and solenoid, needs few specialist tools for maintenance, has armoured counterlungs, uses Searwater electronics (a must-have for me), and all Revo divers seem to like them.
The JJ would be the no-brainer, even GUE have chosen to take a JJ and mutilate it.

Thanks. I would be very interested to find out reasons why would anyone choose a JJ and not a rEvo?

 

[Mas.]

I definitely think it's better. I have benefited from having 5 in my rEvo. I have suffered the consequences of only having 3 (in my Choptima).

Very informative from firsthand experience.

 

[stuartv]

I don't. In fact i am literally asking for help to find a reason not to choose rEvo.

I am a rEvo guy. But some reasons to NOT choose a rEvo that may matter to you:

- it breathes okay, but not great, in perfectly flat trim. It is fine when you're just a little head up (i.e. the trim most people are in when they think they are actually flat). The counterlungs are a back mount design. That means it will generally be at a disadvantage in work of breathing compared to any unit with over the shoulder or chest mount counter lungs.

- It's kind of monolithic to travel with. It needs its own case/suitcase. My Meg friends easily break their units down into a lot more individual pieces and can often pack a lot of it inside the scrubber canister and then fit it all in a suitcase with other stuff. The Choptima (as another example) is lighter and more compact to travel with. I pack my rEvo Micro inside a full-sized regular hard-side suitcase, sandwiched in between two memory foam dog beds and (with the controller and NERD removed and transported separately) it comes in just under 50#.

- The Apeks regs on mine are specific to the rEvo. They use (I believe) standard DS4 service kits. But, the ports for the hoses are machined at different angles than a standard DS4. So, if you ever need to actually replace one, you have to get a rEvo one, not just any old Apeks. I'm not sure if the same is true for the newer units with Mares 1st stages.

- The scrubber size is 6# and you're not going to make that bigger. Well, not in practical terms. If you need a unit that will do longer dives than 6# affords, rEvo is not for you.

- if you are the type to hang out on the surface and talk and also forget to close your DSV, you are going to get water in your unit and then you'll have to get out and de-kit to get the water out. I have one friend that switched from rEvo to Meg for exactly this reason. He flooded his rEvo too many times from talking on the surface and forgetting to close his DSV. With a Meg, you can do that and de-water the exhale lung easily.

- I don't know where you live. Figure out where you would have to take or ship a rEvo to get it serviced. If you don't have ready access to a good service center, rEvo may not be for you.

- If you are reasonably handy, you can fix or replace pretty much everything on a rEvo yourself - except the counterlungs. You'll be paying a factory-trained tech to do that for you when the time comes. Fortunately, I think the official maintenance schedule is to replace them every 5 or 10 years. But, in reality, they last indefinitely. My unit that was built in 2009 still has the original counterlungs. But, whenever they do need to be replaced, it is not a DIY project and it is also not cheap. Not STUPID expensive. But, not cheap, either.

- the scrubber cover is somewhat prone to warping from abuse - especially being left any place where it sits in high heat for an extended period - like possibly a car on a hot day. Once it warps, it won't seal properly and you'll be buying a new one. They are over USD$300.

- the rEvo is a highly integrated design. Most of its parts are rEvo-specific and usually not cheap. There are other units you can buy that are more ... hardware store-friendly.

- depending on where you live, it may be harder to find rEvo instruction. rEvo is very picky about who they allow to become instructors and maintain tight control on that. Unlike most (all? I don't know) other CCR manufacturers, rEvo requires every instructor candidate to be signed off by two separate rEvo Instructor Trainers. That alone substantially cuts down on the number of rEvo instructors out in the world. It's simply harder and more expensive (in time AND money) to become a rEvo instructor than to be an instructor on most other units. As far as I know, anyway, and I certainly invite correction on this point.

 

[AeroSpartacus]

My Choptima has 3 sensors.

Not entirely the point, but the Choptima has 4 sensors - one is HUD only and one is controller only. So you can do similar to what you described with the rEvo, and I have done when my #1 sensor went haywire for a few minutes from condensation

 

[sea_ledford]

That may not equate to "better" to you. But it does, to me!


I use 3L steels all the time. I am definitely over weighted when I dive in a 3mm wetsuit or a rash guard and shorts. It actually seems pretty close to correct weighting when I'm in a 5mm, but I digress.

I was looking at these 10+ years ago, so that certainly colored my outlook on them. Multi cell options were limited to 3 for the controller, then sharing to two revo dreams that had to be calibrated by knocking them together. Some people said it was easy, others had to do it multiple times to get it to work. I'm in the camp of wanting electronic control, but as simple as possible. One reason a Liberty was never on my list.

You have a micro, correct? So the smallest, lightest version is too heavy for a 3mm. Sounds like the trim characteristics workout great for you though. That's fantastic! I dive a Prism2, which is not at all what I would pick for myself for several reasons, but it's what the team dives and is provided for me. And it works just fine. Just like pretty much all the other commercially available units...

 

[Wibble]

Thanks. I would be very interested to find out reasons why would anyone choose a JJ and not a rEvo?

It’s very much horses for courses. A JJ is what I would call a standard layout unit where the cylindrical scrubber canister sits along the diver’s spine between the diluent and oxygen cylinders with external counterlungs close to the diver’s back, over the shoulders, or on their front. There’s a lot of rebreathers with that design including: JJ, AP Inspiration, Megladon, Prism, Fathom, X-CCR and many others.

Most of these rebreathers are capable of extremely deep dives, well beyond 150m/500ft, without modifications.

The Revo cannot be dived beyond 90m/300ft without special modifications and procedures (the oxygen will stop flowing due to the oxygen orifice — need to use offboard oxygen with a standard regulator and drive the unit manually).

The JJ et al mostly have much larger scrubbers than the Revo; more scrubbers means longer dives. At least one person on this forum has swapped his Revo for a Megladon in order to complete longer dives — double the Revo’s scrubber duration.

The design of the “standard” rebreather allows for larger cylinders either side of the scrubber. Some people use the “GUE” configuration where there are two connected 7 litre tanks for the diluent, plus a larger oxygen cylinder and suit inflate cylinder. Sometimes called the “heavy” configuration.

But going back to the horses for courses; not everyone dives below 75m/250ft nor do 5+ hour durations. In fact the vast majority of rebreather divers rarely go below 60m/200ft or longer than 2 hours.