Poseidon xstream mk3

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Bison Ravi

Contributor
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35
Location
Montréal, Canada
# of dives
I just don't log dives
I'm looking to buy new regulators. I presently dive atomic M1 and B1 regulators. They work fine, but looking to try something different.

What is your opinion on poseidon xstreams? The few reviews I've read are either very good or barely ok. Most of the reviews are pretty old, and there's been a few different models (deep 90, amongst others).

The latest models come with an OPV on the first stage instead of the hose, and I believe the purge has been tamed a little bit. Those were common negatives from the older models reviews. I believe they now come with miflex hoses too.

I've read some people saying they breathe amazingly well, with almost no effort in any orientation, and that they breathe very dry. They can be used on any side, so they are supposedly nice for sidemount and for sharing air. Those are things that I'd like for my next regulators, but I can't try them before buying, and they are pretty expensive.

Anyone here has tried the mk3? What are your opinions?

Thanks a lot for your help!
 
So.
The OPV has been on the first stage for a very long time actually. The 3690's have OPV's in the first stage back from the Jetstream days. The hose adapters are brilliant now because you can use standard regulator hoses which saves you a boat load of money down the road. The MK3 has nothing to do with the second stage, but everything to do with the first stage. The MK3 first stage is positively brilliant. Wish I could afford to swap my jetstreams over to the Mk3 first stage.

The model differences aren't actually anything special. The O2 versions have the exact same parts, they're just O2 compatible for anything over 40%. You can make a deep a duration and vice versa.
https://www.divegearexpress.com/regulators/xstream.shtml
best prices will likely be there

I prefer the Jetstream to the Xstream, but that may just be because I have hundreds of hours on the Jetstreams and have only played with the xstreams.

https://www.divegearexpress.com/regulators/jetstream.shtml
there's a link to the jetstreams if you want to look at them. They are both about comparable in terms of breathing, but the real seller for me on the jetstreams is the +_ switch which is great for scooter diving or even just secondary on a suicide strap, since the ability for it to freeflow is about 0. Side exhaust means that they are also very difficult to initiate freeflow at the surface since they have to be placed almost vertically in the water *so have to be rotated 90* to get them to go unlike a traditional second stage which is quite easy to get to freeflow.

Breathing dry is interesting. They do breathe very dry, but clearing them takes a bit of finesse since they have to be turned diaphragm down to get them to blow the water out, so you have to tip your head to the side to get them to clear. Not a huge issue, just a unique trait. Purge button is mostly pointless on these because they are quite violent no matter how they are tuned, so be prepared for it, but they are so small you can just exhale a bit and clear them.

any other questions, feel free to ask.
 
unfortunately it is a unique regulator, so hard to compare
Technically the cracking effort can be made to be just as light as a normal regulator, but because the regulator is pretty much on or off, you can't really "sip" on them like you can with a normal second stage. I don't feel a gush of air coming down my throat unless I hit the purge button and don't have my tongue stopping the mouthpiece properly *you really only do this once by accident and then never again, this was actually during training and a student pushed the button on my jetstream a little too hard*.

WoB is technically a little higher due to the lack of sippability *totally a new word btw :)*, but when you're actually diving it isn't anything worth talking about. There is a reason they are my primary regulators. I didn't realize they had actually changed the cover on the xStream, but since it doesn't have 4 screws holding it in, it may be worth looking at for stage bottles. I wish that link would load all of the pictures, would have been nice to see them.
 
I have the Poseidon Xstreams. I read the reviews of the older Xstreams and they talked about how you could clean the plaque off your teeth with them using the purge valve. I can say with certainty that the current model is no different. Pressing the purge button around students at the dive shop would always startle a few of them. :)

My previous regulators were nice but I found in certain orientation they breathed a little wet. The owner of the dive shop recommended the Xstream because they breathe dry in all orientations. I can confirm this is true. They have always been dry for me. I was also told you can use the left or right (upside down or right side up) so I tried them and this is also true. Mine came with miflex hoses and there is no overpressure on the second stage. There is overpressure on the first stage.

Additionally, I've used quite a few rentals and my original regulators. I found the Xstream breathes easier than all other regulators I have used at any depth (I've used them from 4 feet to 131 feet).

One downside is when I first turn on the air the regulators will free flow. I have to turn on the tanks in one, quick, fluid motion to prevent the regulators from free flowing.

Bottom line, very happy with my Poseidon regulators.
 
they'll always freeflow, no matter how fast you turn the tanks on, it's only about 1 breath though and as soon as the IP catches up it will stop. It's the nature of the upstream design. Also makes it 100% critical you don't let the tank pressure get too close to IP *IP drops 10-15psi or so when you breathe*, and if it gets below the IP required for lockup, freeflow city. You should never have tank pressures below 200psi obviously, but it happens.....

They will breathe a little wet if you have them where the diaphragm is perfectly vertical, but on both the Jetstream and Xstreams that is a very awkward position you aren't liable to be in. On your side, and either head up for jetstream, or head down for X-stream. Not exactly a normal position and it's only a few drops but you can tell it's a bit wet. Certainly not like a normal second stage when it is upside-down though, but the cracking efford does increase if they are diaphragm up due to pressure differentials. Not much, enough to notice.
 
I am a Poseidon loyalist. I have two regsets and admittedly they are the older Jetstream/Odin combination but essentially the same theories of operation. A few thoughts.


--The aforementioned freeflow on opening is unique. "Don't mean nothing" in the big picture just gets the attention of everyone on the boat.

--The need for proprietary hoses is real. But when making a hose swap the added expense is just part of owning them.

--Yes they purge for real on application of force to the purge button but, who cares? In the exceeding rare instance that I actually push the button I just don't push it so hard! Just sayin'.

--Side exhaust is only a problem when diving a wall opposite of exhaust. In my case wall right causes bubbles to cross my face. But at least it is only half the time, right. I have been diving them so long that the standard bottom exhaust regs seem to have bubbles in my face all the time.

--Very dry reg. If it bubbles a bit, turn the vent down give it a cough and viola. Good to go. Standard regs to me now are like breathing through a bong.

--I have been at 170 fsw on the San Francisco Maru and the regulator was not even in my thoughts. Being pretty narc'd and anxious on an aggressive dive like that is natural but the work of breathing never crossed my mind. These things are amazing in their ability to breathe the same at 170 as they do at 30.

--They are harder to get serviced. The parts supply chain out of Sweden dries up occasionally and it can take months to get parts. It takes a good tech to get them right as well. If you find a good one then all is well. If not, well it is also annoying. I had mine serviced by one of the large online shops once and it came back a mess. I also had a tech reuse the seat once and it failed on me during a trip. Now I require old parts for every service.

--They are heavy. Big chunk of chromed brass.

So that is a lot about the old stuff. I can't imagine the newer MK3 would not be better than what I have. Let us know if you enter the dark Swedish underbelly. There is a support group that meets on the third Monday.
 
proprietary hose concern is gone, even on your jetstreams. If you have the 3960 first stages with the OPV in the bottom, https://www.divegearexpress.com/regulators/adapters/hose.shtml $13/second stage and you're back to normal hoses.

the first stages are actually smaller and lighter than most, the new MK3 design is a brilliant little first stage, vastly superior to any other design I've seen. Wish they would put out something with their internals that had a swivel turret with 5th port, but that's a want not a need.
 
I'm looking to buy new regulators. I presently dive atomic M1 and B1 regulators. They work fine, but looking to try something different.

What is your opinion on poseidon xstreams? The few reviews I've read are either very good or barely ok. Most of the reviews are pretty old, and there's been a few different models (deep 90, amongst others).

The latest models come with an OPV on the first stage instead of the hose, and I believe the purge has been tamed a little bit. Those were common negatives from the older models reviews. I believe they now come with miflex hoses too.

I've read some people saying they breathe amazingly well, with almost no effort in any orientation, and that they breathe very dry. They can be used on any side, so they are supposedly nice for sidemount and for sharing air. Those are things that I'd like for my next regulators, but I can't try them before buying, and they are pretty expensive.

Anyone here has tried the mk3? What are your opinions?

Thanks a lot for your help!

Why change something that works?

I had the old deep 180, and while they were quality regulators, they were not right for me.

What I really hated about them was the flow of exhaled air, annoying enough while diving normally, but extremely uncomfortable if you are diving without a mask in really cold water.

I went to Apeks ATX50, and have never turned back, except I went into rebreathers, and got some scubapromk25 first stages for the stagetanks begause of the hose-routing, and I also have one Halcyon second stage. Except for that, everything is DS4/ATX50
 
should have gone Apeks DST instead of the mk25 for the first stages, much better first stages for diving up in your neck of the woods. Check the XTX50's too next time you have to buy gear, the wide exhaust T's really help.
 
https://www.shearwater.com/products/perdix-ai/

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