Scuba Tech Tips: Redundant Air Supply – S04E10

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Safe divers regularly check their air supply and surface before it gets low. However, if you want the extra safety of a fully redundant air supply, Alec shows several popular redundant air options along with the pros and cons of each.

***** Alec Peirce Scuba *****

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Rating: 4.82

  1. Alain Dumesny says

    so I picked up a used Spare Air 3cf and got to test it yesterday coming up from 60ft dive – definitely much harder to breath than my reg (expected since you don't ever want free flow – I have mine inverted upside down attached to tank out of the way, easy grab behind). Mouth piece is very small (have same for my small child) which makes it harder to hold, but mouth cover doesn't fit larger regular piece. slightly neg, then positive when empty – make sure to have a leash (comes with it).
    I was able to come up slow from 60ft and do half of the optional 3min deco at 15ft – the last breath is SLOW and hard (not all sudden) so you know it's coming… you can easily do the last 15ft on that breath…. mind you this was a controlled ascent and I wasn't panicked, but I also would be coming up a lot faster in an emergency at first at least, instead of breathing at higher depth. So far I'm happy, as I'm often separated from my buddy or dive/finish alone.
    the key is not dive as if you have NO redundant air – don't depend on it and hope to never use it. But's it's there tucked away if Murphy's' law happens… I had a first stage internal o-ring blow on me on my old new stock regulator after year of usage or so. Scared me as I was walking into the water – what if it happened at depth ?

  2. Cheesus Sliced says

    speaking as someone who has no idea what they are talking about, would it be a reasonable idea to have BOTH the pony system and spare air? Keep the smaller, lighter, easier one within easy grabbing range at all times, and the bigger, slightly more complex one on your back or with any gear you might have, so you have an intermediate air source that will never leave your side to keep you good til you get your pony ready, or to get to your buddy to use their safe second.

  3. Wally Brown says

    Yes, this is perfect for people that don’t check their air. I was thinking of having one of these systems because I have a friend that was diving in Cozumel with a brand new regulator and it stopped working at 60’. Come to find out his problem obviously wasn’t him, it was a dirty tank. His regulator got plugged up with aluminum dust from tanks not properly maintained by the company we were diving with. Also, this would be a great redundant back up not because of stupidity, but because man made mechanical devises will break at the worst times. Hence, be self reliant, and don’t be in the habit on depending on others (like most people are). As a aviator I believe in redundancy. Airplanes are built with many redundancies for the same purposes as we need under the water. Thanks for the great info Alec.

  4. Anthony Boyette says

    Spare Air…Also known as "Death Can". 🙂

    I'm not sure I agree with your idea that every diver who needs a redundant air supply is sloppy and lazy and wasn't watching his SPG, Alex. I was diving with a girl several years ago and the o-ring on her cylinder extruded at 70 feet. So the "We already know you weren't watching your SPG" thing is false logic. SPG's don't tell you when your o-ring is about to blow. 🙂

  5. Charles Thomas says

    ThunderfOOt brought me here. I like the way you explain this stuff, down to earth and with experience. I just noticed the license plate-the Aqua Lung, that's pretty funny.

  6. Airon Noles says

    This guy has a little bit of Walter White ( without the Meth chemistry ) and "Red" Foreman in him . I like that !

  7. R Silva says


  8. arichidoru says

    Wouldn't it be possible to make something like a "double-chambered" 100cuft (80+20) tank which would allow you to switch? So that one is "very explicitly" told when they ran out of air, but still have some spare left to not die. It should be more convenient to have a single large tank than two, shouldn't it? Although, I know nothing about scuba diving, perhaps this had been tried and failed already.

  9. DerScharfSchutzE says

    I don't even scuba dive but subscribed for this dude's personality !

  10. S says

    Another good redundant air source alternative is Triton. You can get it for $500 for every purchase of Fyre festival tickets. 10% discount for magnises card holders. 🙂

  11. Sebine LifeWind says

    I like this old coot, he's the right amount of funny and condescending.

  12. Ig Ja says

    Thumderf00t brought you quite some traffic whilst debunking scamcl. Have a lovely day.

  13. StuffWriter says

    Was brought here from this video by Thunderf00t:

    Thanks for the info, man.

  14. Lee A says

    Thumderf00t brought me here, and I’m so glad. I’m not a SCUBA diver, but you’re so entertaining to watch and so informative, it’s a bit like watching a documentary. Also, even though I know absolutely nothing, there was no point in this video where I was confused or didn’t know what you were talking about, that shows what a great teacher you are.

  15. Ricardo Fernandes says

    Thunderf00t brought me here.

    Edit: i don´t even swim but its interesting!

  16. Courtney branch says

    Have you done a review on the xs scuba first and second stage ?

  17. Katelyn Grace says

    It`s not just for running out of air it`s also for regulator failure. That`s why I`ve got one.

  18. Jamee Smith says

    Hi Alec. My husband & I are in the beginning stages of shopping for pony systems. What length hose do you recommend for a pony set up? Thanks! We love all of your tech tip videos!

  19. Jacques Poirier says

    what the story does not say is that the second stage of the redundant air system should be setted tight to not loose your air at the immersion, I made such a system with a pile of old rebuilt components, first stage, second stage and a small tank, the only difference is that nothing come from a same manufacturer

  20. Yggdrasil42 says

    I've learned to sidemount this summer. Mostly for less weight on the spine, due to a back injury, but the better balance and trim as well as a fully redundant air supply have turned out great. Would love to see a video on that subject sometime.

  21. vespers_ says

    Why would you give your buddy your spare reg before passing him the pony?

    I'd rather have him use the pony than have us both sharing from the same tank.

  22. Ocean Man says

    Don’t know about other groups in the uk. But my club call these bailout bottles. Great video as always!

  23. justin acosta says

    Alec , I appreciate your work . I didn’t see any thorough videos on how to conduct surface supply air such as a compressor. Also, dive full face masks such as an OTS Aga .
    Thank you

  24. Elyse Van Houzen says

    I suppose these tanks are not allowed in checked luggage on a plane. So what if you dive out of the country regularly. Do dive shops rent them? I have seen a diver's 1st stage malfunction and he started attacking me in a panic, luckily it happened at only about 10' down. It was only a broken mouth piece on his own equipment but it was scary to think if that happened 70' down and your buddy was distracted for 10 secs.

  25. Albert Rodriguez says

    Hello Alec, Love your videos. I have some questions . I got a 19cc Catalina that a buddy of mine gave me so I did the vis and hydro recently and I'm planning to use it as a pony system. It has a yoke valve so I need to know if is there any adapter to be able to use the SS first ad second you are showing in the video or do I need to use a yoke first stage ? and the other question is What is the name of the tank adapter to put it on the side of my 80cc and where to get it ? good night

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