O2 clean regs for back mount doubles?

[geoff w]

I'm planning to start tech training some time in the near future, depending on scheduling everything with the pandemic. From talking to several people, they all use Atomic M1s for their back mount double regs because they're O2 clean and rated for higher percentage O2 right out of the box. After thinking about this for a little bit, it didn't make sense, because you'd need O2 clean for a deco bottle, not back gas. I asked one friend who has his set up this way, he didn't know the reason, and said it's because that's what an instructor recommended to him

Is there any reason to use something like an Atomic M1 for back gas, or is a properly configured Atomic ST1 or similar fine for doubles, and use an M1 for higher percentage O2 stage bottle?

 

[Capt Jim Wyatt]

No need for O2 clean regulators on your back-gas tanks.

 

[tbone1004]

I wouldn't use an M1 if I were you. Aside from being needlessly expensive, you also have to be very diligent about cleaning them since you live in the land of the salty stuff since they're pistons. If you choose to seal them, then you have to worry about them being in direct sun so the lube doesn't bleed out and then have the added cost every service cycle of sealing them. Sealed diaphragms are much easier and have no performance issues to worry about.

Now, that said. Pretty much every high end first stage is O2 clean out of the box. Apeks, Scubapro, HOG, Poseidon, etc. I personally O2 clean all of my first stages now so that I have interchangeability with deco/stage regs. Just one less thing to worry about that doesn't really cost any extra money at time of service for me since I use diaphragm regs and the few pistons I do have are only used in fresh water so I don't bother sealing them.

 

[rjack321]

I wouldn't use an M1 if I were you. Aside from being needlessly expensive, you also have to be very diligent about cleaning them since you live in the land of the salty stuff since they're pistons. If you choose to seal them, then you have to worry about them being in direct sun so the lube doesn't bleed out and then have the added cost every service cycle of sealing them. Sealed diaphragms are much easier and have no performance issues to worry about.

Now, that said. Pretty much every high end first stage is O2 clean out of the box. Apeks, Scubapro, HOG, Poseidon, etc. I personally O2 clean all of my first stages now so that I have interchangeability with deco/stage regs. Just one less thing to worry about that doesn't really cost any extra money at time of service for me since I use diaphragm regs and the few pistons I do have are only used in fresh water so I don't bother sealing them.

Huh? Pistons are suddenly no good in salt water?

You don't need sealed regs really anywhere except the arctic as far as I'm concerned. The mk25 and its atomic children work great

 

[tbone1004]

Huh? Pistons are suddenly no good in salt water?

You don't need sealed regs really anywhere except the arctic as far as I'm concerned. The mk25 and its atomic children work great

they work fine, you just have to pay attention when you soak/rinse them after the dive. Since they offer no benefit in performance over a diaphragm regulator, I opt for the one that's lower maintenance. With a sealed diaphragm you don't have to worry about salt inside the environmental chamber like you do with unsealed regulators.

I recently sold a bunch of MK25's, but I still have a bunch of other piston regulators that I use for deco bottles and I have done plenty of dives in the ocean on my MK25's, but as I've been doing more salty stuff over the last few years I just didn't want to deal with the rinsing worry anymore especially as our boat rides are 3+ hours in NC.

 

[toris1968]

At the neutral buoyancy laboratory we run 46% nitrox and we use Poseidon and Mares as our go to regs. I think we are ditching the mares in the near future

 

[Superlyte27]

Im a repair tech for about 8 major brands. Literally every reg I’m familiar with is O2 clean from the factory.

 

[PfcAJ]

So you don’t “need” o2 clean regs on your back.

However, I believe it makes sense to keep all your stuff o2 clean. I have cannibalized my backgas regs to create a deco reg for a buddy on more than one occasion. Oh your 1st stage is creepin? Here bro take this. Enjoy.

 

[kensuf]

I've got a scubapro mk5 that I've used in one capacity or another since 1981. It is a balanced piston first stage and I've used it almost exclusively in salt water. If you rinse your gear properly after diving, you won't need to do anything special for a piston first stage that you wouldn't have to do for every single second stage on the planet.

 

[CptTightPants21]

To answer the original question.

Every new regulator bought today is O2 clean-even ones that state 'only use up to 40%'. The M1 is made from a unique compound (Monel) that allows them to claim to be able to use up to 80%. This is primarily a marketing gimmick. I would have no hesitation in putting an M1 or a Scubapro MK25 on the deco bottle.

Atomics seem to be a popular brand in Hawaii, the M1 is popular as a 'tech reg', although the Z series (recreational reg) or B would also be fine (if you were to go the Atomic route). With regards to Atomics, they have this special "seat saving" design in the 2nd stage. It means you can't dunk the regs when they are no pressurized because water can enter through the 2nd stage and go up the hose to the first. It also means you should be more careful washing them with a hose.