Regulator choice for 35F fresh water

[eelnoraa]

Not a what regulator to buy thread. My wife and I have a chance to dive in Silfra, Iceland in the upcoming vacation. Water temperature is expect to be 2C-4C (35F to 39F). Normally, she is not into cold water, but for Silfra, she will do it. We have these regulators in our processions:

1. AL legned - this is the top choice for cold water, thus, my wife will be using it

This is what are left for me:
- Mk25AF, G250V, G250V
- Atomic M1 sealed 1st stage, M1 2nd, B2(Ti) 2nd
- Atomic Ti non-sealed 1st, Ti 2nd, B2(Ti) octo.
- I also have 2 HOG D2 2nd stages, but not any HOG 1st.

What is the most cold tolerant reg amount these? I can mix and match if any combination work well. I tried not buy any more reg if not necessary. But if risk of freezing is high, I am open to buying a diaphragm 1st for the trip instead of of sitting out the dives.

Edit: check with dive shop to see what version of Mk25 I have, was told I have M25AF body (not TIS version). It is matte finish with fins just above the turret. Not sure it make any difference tho

 

[buddhasummer]

Of those you've listed I'd go the sealed M1 with M1 second.

Plug: Failing that I've a brand new MK17 Evo for sale, I'm not sure there's any better for cold water diving. I'd pick the G250v with a MK17 Evo, another plug incase you missed the first one.

 

[tbone1004]

I'd probably go with the sealed Atomic of that list but you're really getting close in my opinion. I am not sure what cold tolerance of the seconds from Atomic are like, so may be worth mixing and matching, but I'd probably start there. The first stages should be the least of the concerns in that as long as you behave at the surface

 

[Oldbear]

If you are looking to buy a new kit for her I suggests these two sealed units:
Atomic M1
Scuba Pro Mk17 Evo / G260

 

[buddhasummer]

As luck would have it I have a brand new MK17 Evo for sale going cheap, plug number 3...smiley face...

 

[eelnoraa]

.... I am not sure what cold tolerance of the seconds from Atomic are like, so may be worth mixing and matching, but I'd probably start there. The first stages should be the least of the concerns in that as long as you behave at the surface

Oh this is new to me. I always thought piston 1st stage will be the first issue in cold flesh water. And I thought 2nd stages are mostly similar in design these days - balanced pipet design. What is an good example of cold water 2nd stage?

From some reading, I know that plastic barrel is bad obviously. Titanium barrel is not good either due to small mass and low thermal conductivities. Heat sink on hose fitting area is good, which M1, G250v and HOG all have. Is there anything else I should look for?

If you are looking to buy a new kit for her I suggests these two sealed units:
Atomic M1
Scuba Pro Mk17 Evo / G260

Not for her. She will be using a sealed AL Legend, which I have high confident in. I am trying get some feedback from member to see if piston will do. I am also trying to avoid accumulate gears these day due to my living situation. If M1 will do, the I will just use it. Have anyone do this kind of temperature with lots of success?

As luck would have it I have a brand new MK17 Evo for sale going cheap, plug number 3...smiley face...

Thx for the offer, I am trying to determine if I need it. Will let you know.

 

[tbone1004]

@eelnoraa the piston first stages are really not great, but the piston you have is sealed so it shouldn't be an issue which was that comment. I wouldn't take any of those regs unsealed into 35f water, but sealed shouldn't be an issue.

the second stages are mostly similar, but the amount of metal in there really does matter for heat sinking as does some parts of the case design in general *i.e. why the G250 does better than the S600*. Atomics should be fine though, I'm just not that familiar with their second stages

 

[BoltSnap]

M1, and don't look back. This is what it is made for

 

[cerich]

use the M1 for you... beyond regs, technique matters greatly.

 

[edutravel]

I would certainly go with a sealed reg.

I am posting an AL Legend that was very gently used (one dive trip and some pool time) and then serviced,if you are interested, contact me.

Good luck with your trip. Sounds great!