DIR, warm & cold water technical&cave diving/sidemount regulator

[tbone1004]

Thanks Protondecay, Poseidon Xstream MK was in my list first, but they are out because they are not compliant with DIR diving.

why not? They are not the stereotypical upstream regulator designs and the OPV integrated into the first stage mitigates any theoretical risk of them failing shut. From experience, they work fine with IP creep. If your instructor won't let you use them then so be it, but they are as DIR as I can imagine anything being. The first stage design has the least amount of moving parts and sealing surfaces which minimizes risk of leaks and IP creep. The second stages have less parts, less moving parts, and are a simpler and smaller design. They are no longer using proprietary hoses which was a legitimate issue, and the Xstream and Jetstream use normal IP's. If that doesn't fit the bill of KISS then I don't know what does...

 

[rabe]

Apeks XTX50: robust, versatile, and it breaths really really well.

 

[Protondecay123]

Thanks Protondecay, Poseidon Xstream MK was in my list first, but they are out because they are not compliant with DIR diving.

Non-compliant in what way?

 

[Germie]

DS4 can be used for sidemount without problems. I do it and I just have a 30 cm inflator hose on it. It is way much cheaper than a dst. So for sure it is compliant. If people ask about it, I tell the disadvantages, but also the advantages.

Sidemount and DIR is officially no combination. DIR started as backmount only, open circuit only, hogarthian equipment.

And with Poseidon regs, you also can do all technical diving. I know some instructors won't let you use it, but in standards is not written you have to use brand X or Y. Then just search for a better instructor.

 

[ScubaGypsy]

I don't think the MTX brings anything to the table that the XTX doesn't.

The Apex MTX-R is the premier under ice regulator. It was designed for under ice use to eliminate free flow and is quite effective. The XTX50 is a fine regulator but it is not near robust enough for true ice diving without free flowing. Just check out the difference of the first stage designs between the two.

I use the MTX-R for under ice diving but for my other diving pursuits, including technical and especially travel, I recently purchased the ScubaPro Mk25 EVO/S620 Ti to replace my Mk17/S600 regulators. The S620 breathes 38% better than the S600 while the S600 breathes better than the XTX50 and Atomics. However I have been on too many ice dives that were cut short because my SP Mk17/S600 free flowed. Same thing happened with buddies XTX50s and another buddies Atomic stages. I now use my Mk17/S600s for my stages.

 

[jale]

The Apex MTX-R is the premier under ice regulator. It was designed for under ice use to eliminate free flow and is quite effective. The XTX50 is a fine regulator but it is not near robust enough for true ice diving without free flowing. Just check out the difference of the first stage designs between the two.

I use the MTX-R for under ice diving but for my other diving pursuits, including technical and especially travel, I recently purchased the ScubaPro Mk25 EVO/S620 Ti to replace my Mk17/S600 regulators. The S620 breathes 38% better than the S600 while the S600 breathes better than the XTX50 and Atomics. However I have been on too many ice dives that were cut short because my SP Mk17/S600 free flowed. Same thing happened with buddies XTX50s and another buddies Atomic stages. I now use my Mk17/S600s for my stages.

I can not comment on your points about ice diving as I have never done it.
But I just would like to know if you really feel the 38% difference between the s600 and the S620 and the difference between the S600 and the XTX50 because, frankly, personally I cannot!

 

[ScubaGypsy]

I can not comment on your points about ice diving as I have never done it.
But I just would like to know if you really feel the 38% difference between the s600 and the S620 and the difference between the S600 and the XTX50 because, frankly, personally I cannot!

Certainly can tell it between the S600 and S620 when I go from my S620 on backgas to my S600 stage. My buddy could tell it between his XTC and my S600 when we were doing gas shares in our class. We both ordered the S620 after the class last summer.

 

[jale]

Certainly can tell it between the S600 and S620 when I go from my S620 on backgas to my S600 stage. My buddy could tell it between his XTC and my S600 when we were doing gas shares in our class. We both ordered the S620 after the class last summer.

Wow you are like an ANSI human machine Good for you

 

[tbone1004]

@ScubaGypsy I would say it's "their" premier under-ice design, not "the" design. Poseidon can still dominate that world, it's the second stage that matters far more than the first.

 

[Protondecay123]

I started looking for a good cold water regulator when wreck diving in the Great Lakes piqued my interest. I found many claims of cold water tolerance, but little verifiable literature. I thought to myself, "What regulators does the Navy use?" I will add some literature for your perusal. Some of it is quite dense, but there are a few pearls.
The United States Navy Experimental Diving Unit: Testing in Antartica
Cold Water Scuba Regulator Testing — U.S. Navy vs. EN 250
http://archive.rubicon-foundation.org/xmlui/bitstream/handle/123456789/9908/a549745.pdf?sequence=1
https://oceanfdn.org/wp-content/uploads/2019/08/International-Polar-Diving.pdf