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Air or Nitrox as a diluent?

Discussion in 'Rebreather Diving' started by Capt Jim Wyatt, Mar 18, 2021.

  1. rjack321

    rjack321 ScubaBoard Supporter ScubaBoard Supporter

    # of Dives: 1,000 - 2,499
    Location: Port Orchard, Washington State
    11,174
    5,913
    30min 200ft wreck dive 15/55 dil
    50% and 100% deco gases

    15/55 BO gives you about 5 or 6 mins more deco vs 18/45 BO
    you save about 9 mins on a BO ascent if you're willing to bail to 21/35 (many people treat that as a 218ft MOD)
     
  2. _Ralph

    _Ralph Contributor

    678
    317
    I'm back and forth on the Air vs Nitrox to 30m/100ft ... (STRICTLY RECREATIONAL DIVES)


    One on hand, you have a nitrox mixer on your back (or side), so why pay the extra $$ for a little extra O2?

    On the other hand .... having a gas near your set point means less O2 to inject ...


    Regarding DIL(OUT) ... I'm a standard gas kinda diver ... using the 'next deepest' gas for your planned depth (or expected depth) is my way of diving ...

    So ...

    "Recreational" <30m dive - Air/32%
    30-45m dive - 18/45 (not a fan of 21/35 on CCR ... too limited of a range in use unless you get rid of the Air/Nitrox for shallower dives ... so might as well just go straight to 18/45)
    45-60m dive - 15/55


    Deco for 21/35 and 18/45 are close enough, that if your diving in a mixed team to say 39m, it isn't going to sway much either way (on 1.2 setpoint)

    _R
     

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