First rebreather JJ or Choptima

[dnh]

Going to be getting my first CCR and debating between a CM or BM unit. Have narrowed it down to a JJ or a Choptima. Not going to be traveling much with it, so that advantage of a Choptima isn't such a big deal. My buddy has decided that he's going to get a JJ. Based in SFL. Most of my dives are wreck diving with advanced penetration. Usually in warm water but some months of dry suit diving. Do deco dives up to 150' now but will definitely be going the MOD2 route after 50-100 hours on the unit to dive some deeper wrecks. Not sure if MOD3 is in the future yet, that's quite a ways off. Was thinking that because I'm going to be doing MOD2 will have to sling a bottle regardless of if I use my back mount doubles as dilout with either 50 or 100% so with a Chop I would have backmount doubles, Chop plus that AL80 vs the JJ would have 2 bailouts.
How big of a deal is the chest clutter with the Choptima and loss of the chest D rings? Access to dry suit inflator? Any other pros or cons of one unit over another? Or anything else that I'm not thinking of?
Thanks for the help

 

[Rollin Bonz]

Choptima diver for 3 years about 180 hours. Currently considered MOD2 training. We dive primarily BMD, but have done SM and single BM with the Choptima as well. Most of our diving is dry suit, quarry, shore entry, but have done boat entry ocean dives as well. We almost always carry a AL40 of O2. Usually drop it, but not always.

For background, we did ANDP training and then 2 years of tech diving in SM with 2 AL80 deco bottles before switching to RB, so I'm comfortabl with 4 tanks.

I love my Choptima for all the reasons you are likely familiar with, especially the flexibility to clip it into any configuration I would otherwise dive OC.

I have no issues inflating my DS nor do I have any complaints about chest clutter. I also have no issues carrying, dropping and picking up my AL40, and would not expect to have issues with 2 slung tanks.

But I also have zero experience on any other units.

There is also a lot to be said for diving the same unit as others in your circle.

 

[makar0n]

Going to be getting my first CCR and debating between a CM or BM unit. Have narrowed it down to a JJ or a Choptima. Not going to be traveling much with it, so that advantage of a Choptima isn't such a big deal. My buddy has decided that he's going to get a JJ. Based in SFL. Most of my dives are wreck diving with advanced penetration. Usually in warm water but some months of dry suit diving. Do deco dives up to 150' now but will definitely be going the MOD2 route after 50-100 hours on the unit to dive some deeper wrecks. Not sure if MOD3 is in the future yet, that's quite a ways off. Was thinking that because I'm going to be doing MOD2 will have to sling a bottle regardless of if I use my back mount doubles as dilout with either 50 or 100% so with a Chop I would have backmount doubles, Chop plus that AL80 vs the JJ would have 2 bailouts.
How big of a deal is the chest clutter with the Choptima and loss of the chest D rings? Access to dry suit inflator? Any other pros or cons of one unit over another? Or anything else that I'm not thinking of?
Thanks for the help

Question Thread 'Choptima Rebreather Users and Trimming'

Mar 27, 2025

Okay so I just got my Choptima back from annual service and I need to really nail down my trim. I'm 5'10" 180 lbs. I'm typically leg heavy. My OC sidemount wing (xdeep) is set up such that the being is as low on my bag as possible while still accomodating a butt plate, and 4# on the second from the top spine pocket, and my trim is perfect from full to empty cylinders. With the chop though, even moving the weight to the top most spine pocket, and raising the chop as high as possible (almost to the point where I can't unclip the top clips), the tendancy is still leg heavy. So much so...

• addohm
• Replies: 21
• Forum: Rebreather Diving

Thread 'Flying with a JJ'

Jul 8, 2023

Hello,

If everything goes according to plan, I’ll travel to Florida next spring.
It will be my first time flying with a rebreather.

Are there people who have a nice way to transport a JJ?
Most info I can find is like 8 years old, so I’m wondering if it’s still relevant or if there are better ways.

Thanks a lot!

• Tribal
• Replies: 23
• Forum: Rebreather Diving

Thread 'I'm 99% convinced I'm going to learn to dive on a choptima. Convince me I'm wrong.'

Oct 27, 2024

Like the title says... I'm leaning towards the chop.

I like the simplicity of the kiss, but I am hundreds, maybe 1k+ miles from shallow caves. Most of my training is going to be in deep cool water.

I'm also partial to the jj.

The only no-go for me is bm doubles style valve drills. I don't have the mobility

• VikingDives
• Replies: 18
• Forum: Rebreather Diving

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Thread 'Try dives: Liberty BM/Kiss Spirit/Choptima/Go'

Apr 6, 2025

I was in the market for my first rebreather and try-dived a Liberty Heavy, a Kiss Spirit, and the chest mounted Choptima and Divetalk Go. I wanted to share my experience comparing these units. Here is what I’m currently diving: I have around 400 dives on OC at this point and dive both backmount doubles and sidemount regularly in lakes, ocean, and caves in North Carolina and Florida. On backmount I usually do dives with Iimited deco around 10-20 min, depth up to 40m and usually take one stage. I also like to take photos with a full camera rig. I don’t do a lot of travel but I do have around...

• Handfish
• Replies: 7
• Forum: Rebreather Diving

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Thread 'Wreck Diving with a Choptima?'

Dec 27, 2024

Sadly, the only instructors around me teach the Prism 2. So I know I'll probably be able to find a location to do a try dive on that unit at some point.

However a buddy of mine has a Choptima. He sems to like it but he's mostly diving cave country with it. I'm not against going into a cave. However my main goal is dive the Oriskany as often as possible because it's a bit closer than cave country and there are other cool things to see in the Pensacola area.

My buddy hasn't done anything past 120' from what I can remember. I'll have to ask him when he gets back from the holidays.

I'm...

• Mike VonDebag
• Replies: 16
• Forum: Rebreather Diving

Thread 'Most compact/travel-friendly CCR - Sidewinder, Optima CH or ??'

Jun 15, 2025

Folks, what is the most compact or travel-friendly CCR in the market?

I am looking to get one primarily for photography and since this involves travel to a lot of destinations which arent necessarily set up with full tec shops, I need something that is light and travel friendly. Was looking at the Sidewinder or the Optima - the Optima CH seems interesting as it is (a) light and (b) will integrate well with a regular harness. Anything else i should look at?

TIA!

PS: FWIW - am trimix certified from the late 90s, and have tried out a couple of CCRs in the past (WAY in the past)...

• vkalia
• Replies: 52
• Forum: Rebreather Diving

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Thread 'Wisdom Required'

Nov 30, 2024

I am looking at getting my first rebreather, im an AN / DP Sidemount diver based in Asia but travel for diving 2-3 times a year within the region.

I have narrowed it down to 2 primary choices

1). Choptima - travel friendly, robust, trimix compatible for future growth. / small counter lungs doesn't seem to be much service capacity in Asia

2). JJ - Well catered for in SEA, CE Certified, indestructible, will do anything / Not travel friendly

First question:

1). are my above assumptions on point?
2). Will a Choptima handle cold water diving?
3). I am a big bloke, will maller counter...

• EE-JIT
• Replies: 6
• Forum: Rebreather Diving

Thread 'O2ptimaCM and Trim'

Dec 14, 2024

Has anyone tried LOWERING the unit to improve "heavy leg" trim? I know it seems counter intuitive but Im curious if moving the counter lungs closer to your hips changes the center of buoyancy downwards or not.

• addohm
• Replies: 39
• Forum: Rebreather Diving

• 

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Thread 'FXCCR vs cmptima'

Oct 4, 2024

curious to hear opinion on those two and comparison since now the FXCCR being out for a little while. What are the pros and cons on these specific unit!

• sebdiver
• diverite fxccr optima cm xccr
• Replies: 6
• Forum: Rebreather Diving

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Thread 'The New Dive Rite Optima CM - My 30 Hour Review'

Mar 16, 2020

I started diving rebreathers some time ago. I got caught up in a very well marketed rebreather from overseas that was taking the US by storm. And a lot of you probably remember that I would come here and post how it was the greatest rebreather ever, having never dove any other rebreather in my life. And then a good friend of mine, Jon Bernot, challenged me (actually dared me) to try the Dive Rite Optima. I sold my rebreather the next day and with the help of Jon and Cave Country Dive Shop, we got me into my first fully electronic rebreather. I was in love with the Optima (So much so...

• Superlyte27
• Replies: 283
• Forum: Rebreather Diving

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Thread 'Just tried 3 CCRs (Fathom, rEvo, Choptima)'

Nov 8, 2022

First of all, a huge thanks to Ben Lair from Paragon Dive Group (@DiveTucson ) for helping me test the rEvo and Choptima today!

Keep in mind, I'm still a newb, so take what I write below as just personal notes for myself; which shouldn't be used as any type of authoritative information for comparison, etc.

Yesterday Fathom did a try dive, which I've been looking forward to for months. Charlie, the owner of Fathom, did a complete build from start to finish at which point we had a choice of diving a "cave" or a "tech" setup. Cave setup being lighter, more compact, with the DIL/BO...

• boriss
• ccrs choptima eccr fathom ccr hccr mccr optima cm rebreathers revo revo rebreather
• Replies: 71
• Forum: Rebreather Diving

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Thread 'JJ vs Cmoptima vs Xccr(fx)'

Jul 28, 2024

Hi all new here,
foudn this from the Rebreather forum!,

My question might trigger some of you but, which one will you go for? I tried 2 of the 4 liste above and can't decide which one I like.
In your opinion which one make the most sense, which one do you prefer, the sturdiest one? All instructor are close by max 4h around here.

JJ?
Xccr was good
CMoptima feel a bit snug on the chest im not tall
FXCCR new to the market!

• sebdiver
• rebreather
• Replies: 36
• Forum: Rebreather Diving

And probably a few more topics here and there...

 

[Dsix36]

For what dive you will be doing, I would say the JJ rather than a Choptima. I sold my Choptima and went back to my rEvo for multiple reason (most of which you already stated). If I were going for another chestmount it would be a smaller unit that is manual like the GBM.

 

[broncobowsher]

For what dive you will be doing, I would say the JJ rather than a Choptima. I sold my Choptima and went back to my rEvo for multiple reason (most of which you already stated). If I were going for another chestmount it would be a smaller unit that is manual like the GBM.

I dive (rEvo) with a bunch of Choptima divers. I see them. I just don't get excited about them. I can't see the hype. I've dropped into holes on ships in Truk that they couldn't get through. I know they could configure in a way to get through. Yea, undo a couple clips and hand it off to the boat crew. Nice.

The rEvo isn't perfect, none of them are. Picking through what you plan to use it for and which one better matches. Makes sense. Easy to say. Hard to do. Hard because of what is important to you and not someone else. Chest clutter is a big put off for me personally.

 

[Heat Miser]

I dive both a Choptima and a rEvo (and some of my friends, dive a rEvo in a very similar fashion to a JJ, they block the CMF, they unblock the AP reg and switch over the controllers to make it an e-ccr).

Generally the Choptima will trim out better, may have worse WOB than the JJ. Is less durable. Can be used with more effect on specialist dives. It actually works very well for very deep +100m dives because with a twinset you can carry more back/bailout gas. The ability to rig it in sidemount is nice in a cave, its slightly cheaper and it works well for shallow boat dives because you can use it in single tank backmount.

The JJ is more robust, everyman and his dog has one, and your buddies dive it so you can get help from them checking replacing parts. Its heavier.

Without knowing you, buy the one your going to dive more with buddies.

 

[dnh]

Choptima diver for 3 years about 180 hours. Currently considered MOD2 training. We dive primarily BMD, but have done SM and single BM with the Choptima as well. Most of our diving is dry suit, quarry, shore entry, but have done boat entry ocean dives as well. We almost always carry a AL40 of O2. Usually drop it, but not always.

For background, we did ANDP training and then 2 years of tech diving in SM with 2 AL80 deco bottles before switching to RB, so I'm comfortabl with 4 tanks.

I love my Choptima for all the reasons you are likely familiar with, especially the flexibility to clip it into any configuration I would otherwise dive OC.

I have no issues inflating my DS nor do I have any complaints about chest clutter. I also have no issues carrying, dropping and picking up my AL40, and would not expect to have issues with 2 slung tanks.

But I also have zero experience on any other units.

There is also a lot to be said for diving the same unit as others in your circle.

Has your breathing pattern changed from OC to the Chop? I've heard some people say that they assisted the way they breath to slightly shallower breaths. One guys said he kept bottoming out the loop when he took a large breath

Most of the people in my area dive one of these 2 units.

 

[Rollin Bonz]

Has your breathing pattern changed from OC to the Chop? I've heard some people say that they assisted the way they breath to slightly shallower breaths. One guys said he kept bottoming out the loop when he took a large breath

Most of the people in my area dive one of these 2 units.

Couple of comments on the counter lungs...

There's been at least 3 versions.

We did our initial training in 2022. I bought a new unit while @stretchthepenn bought a used one.

He can speak more to the specifics, but during training, we found HIS unit was bottoming out on him. Mine was fine. We are similarly in size 6'3-6'4" 240ish.
We talked to Lamar and the guys at DR, and they checked his unit out and said he had a smaller (5L), older CLs.

They immediately upgraded him to the new 2022 (6L) lungs (at n/c if I recall). He had no issue bottoming those out afterwards.

The newest CLs (2023) were originally dubbed 3D, although I think they dropped that term, and are even larger volume in the same sized outer bag as a result of a more complex CL structured with more individual panels. I'm not sure the volume. I upgraded to them last year and they are well worth it. There is no way any human is going to bottom those out.

Breathing pattern from OC is likely completely different. On the Choptima, as well as any other RB I'm sure, as you grow accustomed to it, you fall into a much more relaxed "normal" breathing pattern as you'd experience on the surface.

There's no more "breathing effects buoyancy" so you can ACTUALLY "just breath normally"

 

[dnh]

Couple of comments on the counter lungs...

There's been at least 3 versions.

We did our initial training in 2022. I bought a new unit while @stretchthepenn bought a used one.

He can speak more to the specifics, but during training, we found HIS unit was bottoming out on him. Mine was fine. We are similarly in size 6'3-6'4" 240ish.
We talked to Lamar and the guys at DR, and they checked his unit out and said he had a smaller (5L), older CLs.

They immediately upgraded him to the new 2022 (6L) lungs (at n/c if I recall). He had no issue bottoming those out afterwards.

The newest CLs (2023) were originally dubbed 3D, although I think they dropped that term, and are even larger volume in the same sized outer bag as a result of a more complex CL structured with more individual panels. I'm not sure the volume. I upgraded to them last year and they are well worth it. There is no way any human is going to bottom those out.

Breathing pattern from OC is likely completely different. On the Choptima, as well as any other RB I'm sure, as you grow accustomed to it, you fall into a much more relaxed "normal" breathing pattern as you'd experience on the surface.

There's no more "breathing effects buoyancy" so you can ACTUALLY "just breath normally"

Thanks. That makes sense. I did a try dive and didn't bottom it out, but I was also only at 15-20 ft.

I remember liking it after the try dive, but was little concerned with the chest clutter since that's something that I didn't pay attention to during the try dive

 

[stretchthepenn]

I dive (rEvo) with a bunch of Choptima divers. I see them. I just don't get excited about them. I can't see the hype. I've dropped into holes on ships in Truk that they couldn't get through. I know they could configure in a way to get through.

Unsnap from the two hip D-rings, do a Superman pose, reclip. Pretty simple, really.