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15l tanks

Discussion in 'Cozumel' started by flyboy08, Nov 28, 2019.

  1. flyboy08

    flyboy08 ScubaBoard Supporter ScubaBoard Supporter

    # of Dives: 500 - 999
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    They are Catalina 100 aluminum.
     
  2. I especally agree with "the bulk of the Aluminum 100 or low pressure steel 120s is difficult to dive with. In fact it is my belief that dealing with the bulk of them may cause more divers to use up any extra air to be found in the tank." Those things are huge 'missile silos' both above and below the water and often result in 'one step forward, two steps back' with respect to manageability.
     
  3. BRT

    BRT Giant Squid

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    I think if you happen to get the standard 3000# fill on the LP120 you will have enough air to overcome any additional bulk.
     
  4. GameChanger

    GameChanger Professional Photographer

    # of Dives: 500 - 999
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    Hi Dave,
    Per my dive logs, all fills for the 10 dives using the 100AL's were over 3100 psi. It should be noted that it is not uncommon for me to get 80AL tanks that are 2700 - 2950 psi. I will reject any tank below 2900. I honestly didn't notice any buoyancy issues during any part of my dives. Good buoyancy has never been an issue for me though, regardless of what gear I am using. I am a bit of a gas hog and I have to focus on good breathing techniques when using 80's. With the 100's I did get longer bottom times and even though I still focused on good breathing techniques, I was always last to surface with the DM. I have wanted to try the steel 120's and perhaps I will on my next Coz trip this April.
     
    flyboy08 likes this.
  5. Dave Dillehay

    Dave Dillehay Dive Shop

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    Im glad to hear that some of your Aluminum 100s were up to 3100 PSI. Perhaps Meridiano 87 has gotten some message but at 3100 you are still not near 100cf. As for the HP 120s you can get while diving with Aldora which has its own fill station which happened after repeated short fills. Liquid Blue also has HP120s but I don't know how they fill their tanks.

    Dave Dillehay

    Again NO financial interest in Aldora Divers
     
  6. flyboy08

    flyboy08 ScubaBoard Supporter ScubaBoard Supporter

    # of Dives: 500 - 999
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    What is the max psi for an aluminum 100/15L? I'm paying $15 a tank for this privilege, and I better get decent fills.
     
  7. JackD342

    JackD342 Dive Shop

    # of Dives: 500 - 999
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    Generally (I think probably always) the service pressure is 3300 PSI.

    So you understand why it may not be as simple as one might think to get that fill:

    Tanks at all but the smallest operations are probably not filled one at a time, with someone monitoring the PSI. There are banks of multiple fill whips attached to rows of tanks, and a regulator in the line that is set to stop the fill at a certain pressure, probably 3000. With the regulators that I am familiar with, even temporarily adjusting that regulator up to a higher (or lower) pressure is not as simple as turning the dial to a preset position. It takes a little more effort to zero in on the desired set, and then the same effort to return it where it was.

    Now, even if you have a fill station that makes that effort, or does enough 3300 fills to have a separate line with a regulator set for that pressure, you will also have an issue with the PSI falling a bit as the warm/hot tank fill cools down. Again, is the operation taking the time to go back and top off, or just leaving it at a "close enough" value? While I am sure many operations overfill in anticipation of the tanking cooling down to about where it should be, topping it off is the "by the book" method and no one should be faulted for following it.
     
    flyboy08 likes this.
  8. couv

    couv Instructor, Scuba

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    Well, perhaps my math is fuzzy, but I think you should consider going the Aldora route. If you're shelling out $30 extra per trip for AL 100s (meaning you'll get anywhere from 90-100 cu ft) vs 120 cu ft. If I understand correctly, the 120ies are included in Aldora's price. One would have to get a heck of a deal to make up the difference. Even then, you're short 20 cu ft.

    I too find steel tanks more comfortable in the water than Al. In fact, I would take a good old 72 (71.2 cu ft @ 2475 psi) over an Al 80 any day-I know to others it does not seem to matter.
     
    flyboy08 likes this.
  9. flyboy08

    flyboy08 ScubaBoard Supporter ScubaBoard Supporter

    # of Dives: 500 - 999
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    Yea, but nitrox is included so it's a wash.
     
  10. couv

    couv Instructor, Scuba

    # of Dives: 1,000 - 2,499
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    Again my math might be a bit fuzzy, but if IRCC Aldora only charges about $10 for nitrox so your Al 100 for $30 vs steel 120ies for $20 doesn't seem a wash to me. Not to mention, if your "100s" are filled to:
    psi-----cu ft
    3000 = 90
    3100 = 93
    3300 = 100
     
    Dave Dillehay likes this.

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