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Opinions

Discussion in 'Poseidon' started by Kharon, Mar 18, 2019.

  1. Kharon

    Kharon Solo Diver

    # of Dives: 200 - 499
    Location: Upstate NY
    3,741
    3,051
    113
    Talking about reliability statistics - anyone have feelings on Poseidon 2nd stages. I've pretty much decided to toss the Hollis 500SE and go back to my Cressi XS2. I wanted a side exhaust and plugged the right side escape vents with marine goop on the Cressi. It worked fine. Then I got the Hollis and it worked wonderfully - for a time. Then it crapped the bed on my Bonaire trip. I don't want more problems. I can service the Cressi. Would a Poseidon be totally reliable? I've heard they are a PITA about IP pressure. I don't want a reg I have to eff around with like a Fiat every time I start up.
     
  2. tursiops

    tursiops Marine Scientist and Master Instructor ScubaBoard Supporter

    # of Dives: 2,500 - 4,999
    Location: U.S. East Coast
    7,803
    5,465
    113
    Nothing will be "totally reliable" especially for someone who is pretty much critical of everything , as you are. Just sayin'.
     
  3. Protondecay123

    Protondecay123 Barracuda

    # of Dives: 0 - 24
    Location: Arkansas
    300
    165
    43
    Using what for a 1st Stage?
     
  4. Caveeagle

    Caveeagle Rebreather Pilot

    # of Dives: 500 - 999
    Location: High Springs, FL
    1,463
    949
    113
    Poseidon regs are extremely reliable. There is a ton of misinformation floating around about them. The “high IP” only relates to the cyklon regs. Both the Jetstream and Xstream regs operate very well around a typical 125-135 IP.

    They are also some of the easiest regs out there to find service parts for.
     
  5. Kharon

    Kharon Solo Diver

    # of Dives: 200 - 499
    Location: Upstate NY
    3,741
    3,051
    113
    Shouldn't matter if the IP is set right.
     
  6. tbone1004

    tbone1004 ScubaBoard Supporter ScubaBoard Supporter

    # of Dives: I'm a Fish!
    Location: Greenville, South Carolina, United States
    15,683
    7,014
    113
    I use Poseidon Jetstreams almost exclusively. Once they are set, they will go years without needing anything.
    Now, the problem is getting them set properly.
    What is important to remember is that these are unbalanced, non-adjustable, upstream second stages. What this means is that when you tune them to the bitter edge, it is CRITICAL that the IP is set properly as even a 1psi difference is enough to cause it to leak.

    With the 3960 first stage as seen with most Jetstreams, the balancing is not all that great and it is inversely proportional to the supply pressure. Since it is inversely proportional, when they say you need to hook the first stage up to a high pressure supply bottle when servicing, they aren't kidding. Upstream valves need to be set at the minimum IP they will see during service.
    The IP swing on the 3960 from 4000psi down to 300psi is about 20psi so it is not insignificant. I have done some field adjustments of first stages where the supply was only about 3100-3200psi, and when that first stage went on a cave filled bottle around 3800psi, the second stage was leaking as the IP was too low. I try to set the IP at 4000psi and tune the second stages at the 4000psi supply with an IP of 120-125. The IP will go up as the tank pressure goes down, so the regs won't freeflow until tank pressure is below about 200psi. When they do that, you finish an inhale and they'll give a light bubble before locking up. That's a great indicator on a stage bottle that it's time to switch and what I use when cave diving instead of checking spg's, neat little trick.

    While the above is the protocol for the Xstreams and Jetstreams which use an unbalanced-upstream valve, the Cyklon is an unbalanced-downstream valve. With a downstream valve, you need to adjust the IP at the maximum IP, so the first stage IP adjustment, and second stage cracking adjustment need to be done at minimum supply pressure when using a Cyklon vs. maximum supply pressure with the Jetstream/Xstream

    That initial setup is a lot more finicky than say a Scubapro G250 where you put the adjustment tool on there, turn the knob all the way out, turn until it hisses a little bit and back it off. That said, once it's done, you don't have to do anything for several years and they don't just randomly go out of adjustment
     
  7. Protondecay123

    Protondecay123 Barracuda

    # of Dives: 0 - 24
    Location: Arkansas
    300
    165
    43
    And is a 1st that will hold its IP.
     
  8. tbone1004

    tbone1004 ScubaBoard Supporter ScubaBoard Supporter

    # of Dives: I'm a Fish!
    Location: Greenville, South Carolina, United States
    15,683
    7,014
    113
    The Poseidon first stages all hold their IP very well, and for a very long time due to the unique bullet or sphere design vs. a hard crown that cuts a groove into the seats. The important part is how well they are balanced and adjusting the second stage cracking efforts at the right point in the IP balance.
     
    Protondecay123 likes this.
  9. Protondecay123

    Protondecay123 Barracuda

    # of Dives: 0 - 24
    Location: Arkansas
    300
    165
    43
    Those were some of the issues I was curious about the potential setup with having a non-Poseidon 1st Stage. (Frankenregulator)
     
  10. Kharon

    Kharon Solo Diver

    # of Dives: 200 - 499
    Location: Upstate NY
    3,741
    3,051
    113
    And acccording to ad claims by Poseidon re. the paired 1st stage, the IP changes due to depth and gas density so the 2nd stage should be immune to IP deviance.
     

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