Best Regs for Extreme Cold

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I dive in cold water from time to time, and people around here do ice diving.

Aside from clearly unsuitable designs, like unsealed piston 1st stages,

The ScubaPro Mk 25 EVO is an unsealed piston 1st stage. I would not call it "clearly unsuitable" at all. Personally, I would not hesitate for a second to dive my Mk 25 EVO+G260 setup in -1C water. At least, the regs would not be the source of any hesitation... :D
 
Aside from clearly unsuitable designs, like unsealed piston 1st stages,

I'm not even convinced that using an "environmentally sealed" diaphragm regulator provides useful freezeup resistance, compared to a non-environmentally sealed diaphragm.

Early piston regs had issues with cold water. The Mk25EVO has gone through some significant design changes which makes it more tolerant in cold water.

The nice thing about the "environmentally sealed" reg is it keeps the inside of the reg cleaner than the none sealed.

_________________

The one thing I see/hear a lot of when it comes to cold water regs is the focus on first stages. The second stage plays just an important role. I've seen far more second stages freeze up and fail than first stages.
 
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I think ScubaPro says that the Mk 25 EVO is just as cold-tolerant as the Mk 17...

To me, cold is not a reason to shun the Mk 25 EVO.
 
Why is it unbeatable?

Both the first and second stage are, for all intents, environmentally sealed (dry).

With proper use of the Argonaut DSV mouthpiece, even the mouthpiece should stay dry.


The Royal Aqua Master was used in Antarctica into the early 90's. That is 20 years after they quit producing them. From what I have read, their reliability only dropped after replacement parts were not available anymore.
 
Well, Luis, you've given me courage. Perhaps I'll try to follow @rhwestfall underneath the crunchy stuff.
I just got my DSV mouthpiece a couple of months ago. Thanks!

A buddy sent me some of the discussion after the release of that Antarctic data, and the criticism indeed seemed bogus, given the age and maintenance of the DH stuff they "tested."
I'm game. I guess I'll have use for my DUI 450 liner after all. :D

I guess these are worth sharing again. I'm not the first to post them:
Cold Water Regulator Blues
How bout that pic of an old dry bleed Sherwood that didn't freeflow!
Cold Water Scuba Regulator Testing — U.S. Navy vs. EN 250
 
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If those are your true temps, I'd choose environmental sealing - either a sealed Atomic piston, or a sealed diaphragm like the XTX200 or Scubapro Mk17/19. Has your XStream EVER iced up?

Amazingly no, the XStream never iced up. Occasionally when working hard in around 0° I would inhale a pellet of ice or two, but that is 100% acceptable given conditions. A good warning sign though to be aware of possible freeflow.

Just curious as to why another XStream isn't your immediate choice? From your list, I'd likely stay with them.....

Since I've got to replace them I was curious to see what else was on the market. I did like them a lot but I'm always keen to see what else is out there.

Thanks very much for the input everyone.
 
Well, whatever you do, don't sell the Poseidons. Buy a new one if you want to check out what else works , but you may be disappointed. They are bulletproof. PM me if you want me to restore them. I have a full stock of spare parts and am certified to service Poseidon.
 
Why would you want to get rid of your Poseidon Xstreams? They have been bullet proof for us in our environment...under ice, Great Lakes below the thermoclines etc. Our mean bottom water temp. is 4C but up at Les Escoumins We have seen -1C on our computers while diving. No problems with our Xstreams so far in those conditions make me think that your regs just need a service to keep them in tip top shape.
 
A buddy sent me some of the discussion after the release of that Antarctic data, and the criticism indeed seemed bogus, given the age and maintenance of the DH stuff they "tested."

The problem is Antarctic diving data was not recorded until 1989 or 90. As Luis points out the newest double house would be 15 years old by then. If they had data from all diving seasons then we could check the failure rate of the regulators over time. Even then it is difficult to tell because maintenance and training are important factors. I remember on study where the bulk of the regulator failures happened to a single diver, so evidently he must have been doing something wrong.
 
https://www.shearwater.com/products/swift/

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