Best 1st and 2nd Stage for under the Ice?

[Rick Inman]

I don't know which is the best reg, but I like my Atomic M1, which has the environmentally sealed first stage.

 

[jpedwards]

Yep, good info so far. DA AquaMaster brouht up a few good points. So what is it really that makes a reg good for cold water, and does any of that subtract from the same reg being good for our favorite tropical places? Maybe it's just me, but I'd like to hear more about the internal workings ...

 

[OliveBone]

My vote is for the Apexs ATX200, love those regs. Never had a problem with them under the ice, nor has anyone else that I know that dives them.

 

[Gary D.]

Our entire team is in and will stay in Sherwoods. Sherwood along with Posiden have been the only consistant trouble free regs we have used.

Maintence is much easier with the Sherwoods than Posiden.

Gary D.

 

[DA Aquamaster]

Yep, good info so far. DA AquaMaster brouht up a few good points. So what is it really that makes a reg good for cold water, and does any of that subtract from the same reg being good for our favorite tropical places? Maybe it's just me, but I'd like to hear more about the internal workings ...

Properly designing a first stage for use in cold water will not detract from its warm water performance at all.

In fact the opposite is usually true. For example, to improve the cold water reliability of the Mk 25 (which is not all that well suited to cold water use as there is little or no safety margin if good cold water technique is not used) SP recommends what amounts to a general detuning of the regulator with lower intermediate pressure and a higher inhalation effort. So in effect, when cold water ready, your expensive Mk 25 S600 breathes worse than a Mk 2 R190 that has no issues with freezing in cold water and the Mk 2 R190 cost several hundred less. And what is worse, your Mk 25 S600 will preform equally badly on warm water dives where the detuning is not needed. In that case it makes far morse sense to just buy a Mk 2 R190 or Mk 16 R390 and save big bucks.

If the first stage is sealed or alternatively has very large, open and easy to rinse ports in the ambient chamber it will also benefit the reg in warm water as it will be less prone to corrosion, salt, sand and silt deposition, so there is not really a downside.

Cold water second stages tend to be designed for improved heat reansfer from the relatively warmer surrounding water. Even at 33 degrees, the water is warmer than the incoming air. This usually involves metal air barrels or heat transfer fins which usually have a side benefit of causing condensation to form from your exhaled breath which is then re-inspired in your next inhaltion and this greatly reduces dry mouth. An old metal cased/metal air barrelled second stage like the Balanced Adjustable is nearly impossible to beat in this regard and on commerical dives where I may be in the water 4-6 hours per day, they are my preference.

 

[Bob3]

Have a look at the innards of the latest offering from Poseidon, the Xstream 1st stage; the critter uses a honkin' big thermodynamic heatsink mass to keep the 1st stage mischief free. (most all freeflows are due to icing in the 1st stage)


For ice diving, I like to use a double hose (Nemrod Snark III or USD Royal AquaMaster) as a primary reg & have a Poseidon Cyklon on a bailout to pass off to the lads that have their regs freeze up.