Welcome back to the Poseidon Forum!

[rsingler]

So, are the Poseidon's first stages sold new with cyklon's second stage just tuned to a higher IP ?

Yes

 

[grantmac]

I am oddly fascinated by the Cyklon, that simplicity and metal construction seems like it would make a brilliant deco reg (where the Jetstream is not my preference).
Can anyone provide feedback on how they breathe?

 

[rsingler]

Simple downstream valve. All metal valve construction makes it robust, tho sensitive to verdigris if not well rinsed.
Tho' tuning cracking effort is not mentioned in the manual, I tune mine to 1.1" easily. Nicest thing is there's virtually no case geometry fault. Rolling loops does nothing. Gets a touch stiffer if your roll your head to the left, but nothing like a standard reg looking up.
Some cavers run a lighter IP, but Poseidon doesn't recommend it. Tuning gets a little more sensitive. But easy valve to pressurize and then turn tank off.
Breathing is smooth and easy at spec IP if tuned light, and large exhaust makes for low WOB.

 

[Jake 10]

Poseidon Diving Logistics, LLC, @PoseidonDiving.US has been given responsibility for Poseidon regulator and rebreather distribution, service and training in the US.
My name is Robert Singler, and I am Poseidon's Senior Technician Instructor Trainer for the US.

We want to welcome you back to the Poseidon manufacturer's forum! Going forward, we hope that this forum will be a place for you to get answers to your questions from folks who have direct contact with headquarters in Sweden.

We look forward to gradually dispelling some of the myths out there, to explaining why the unique designs of Poseidon's regulators have made them a reg of choice for many of the world's militaries, and how they meet certification standards at 600 feet.

I plan to gradually extend technician training beyond dive shops, so that interested owners can service their own gear and not have to rely on an unknown to service their life support equipment.

I will personally try to ensure that going forward, the technicians I train will service your regs with the same care and skill that I give to my own equipment.

Here's to the disappearance of urban myth!

thank you Robert (Bob)

 

[grantmac]

Simple downstream valve. All metal valve construction makes it robust, tho sensitive to verdigris if not well rinsed.
Tho' tuning cracking effort is not mentioned in the manual, I tune mine to 1.1" easily. Nicest thing is there's virtually no case geometry fault. Rolling loops does nothing. Gets a touch stiffer if your roll your head to the left, but nothing like a standard reg looking up.
Some cavers run a lighter IP, but Poseidon doesn't recommend it. Tuning gets a little more sensitive. But easy valve to pressurize and then turn tank off.
Breathing is smooth and easy at spec IP if tuned light, and large exhaust makes for low WOB.

Honestly I just don't seem to be getting used to the Jetstream breathing feel after many successive retunes. I may just prefer a downstream reg, the idea of one that has no orientation and very simple design is appealing.

I guess I've got a new eBay hunt to go on.

 

[Mobulai]

Just bare in mind the old 300s have a very wide mouthpiece — standard ones wont fit

 

[grantmac]

Noted! Is there a metal version of the narrow design? I much prefer the Apeks anti-fatigue style mouthpieces.

 

[Mobulai]

Noted! Is there a metal version of the narrow design? I much prefer the Apeks anti-fatigue style mouthpieces.

The 5000s — I think

 

[rsingler]

Honestly I just don't seem to be getting used to the Jetstream breathing feel after many successive retunes. I may just prefer a downstream reg...

There is no disputing that the Xstream/Jetstream design has a different feel to it. You cannot sip from this reg. The valve opens, and it closes. It's a shift in expectations.
That said, there is also no denying the several advantages of the design. If all you do is 50 ft lazy dives from a boat in Bonaire (wouldn't that be nice!), you'll feel that the air delivery is more natural with a barrel design. When demand is low, sipping small breaths without effort from a reg feels closer to natural breathing.
But that ignores the physics of diving, where effort and increased gas density play a significant role in CO2 elimination. Sipping is bad technique for diving, even if it's the way you're used to breathing in your Barcalounger. Add in gas density, and the increased competition CO2 molecules have for exposure to the alveoli, and full measured breaths with full exhalation are the better way to breathe. Now add some current, and gas delivery becomes key.
This is where the servo design shines. The outflow area of the valve is huge. This becomes important at depth, where the ratio of IP to ambient drops by 60%. That means that the contribution of gas expansion to the volume of your breath also drops by 60%, so you need a valve that can deliver. This design delivers, and was the only reg to not ice over on an Antarctic test back in 2004. It's got one moving part and no dynamic o-rings, so unless you step on the case and bend the servo, it's pretty much indestructible.
But yeah. It feels different, and though you can make it much smoother by dropping IP into the 109‐115 range, sometimes it is hard to ignore the feel. But for deep dives, it's pretty awesome. There are only a few that can claim certification at Norsok standards (600').

 

[grantmac]

The breathing feel is off-putting enough that I've felt close to hypercapnia on a pretty mellow dive actually. Where on my Apeks I've done much higher effort without issue.
I continue to dive them because I like the durability, form factor and insensitivity to orientation. The breathing feel is not pleasant.