octo question

[gwharris]

I have a poseidon cyclon regulator and I was wondering if any octopuss would work with it or do I need a special one. Thanks

 

[DA Aquamaster]

A regular downstream octo should work as long as it is adjusted to operate at the intermediate pressure of your particular first stage.

 

[scubatoys]

And unless it's a really old one - virtually any octo should work at that pressure.

 

[rescuediver009]

And unless it's a really old one - virtually any octo should work at that pressure.

Larry I was always under the impression that Poseidons operate and an IP that increases as the the supply pressure decreases, thus causing a regular octo to freeflow? I realize that the initial higher IP would makeother octos explode but they weren't exactly intended for each other. All Poseidons except the new Xstream?

 

[scubatoys]

Larry I was always under the impression that Poseidons operate and an IP that increases as the the supply pressure decreases, thus causing a regular octo to freeflow? I realize that the initial higher IP would makeother octos explode but they weren't exactly intended for each other. All Poseidons except the new Xstream?

Not really enough to do anything... I dove a poseidon for years with both a standard octo, and an Air II system hooked to the poseidon 1st stage.

The only thing that is weird about poseidons, is when your pressure is low - the Odin second stage won't seal... For fun some time kick on a tank just a little bit with a Jetstream Odin, and the second stage will be free flowing along... You have to crank on the valve to get the pressure up to get the second stage to stop free flowing... but just the odin - not your octo.

So the thing that happens is when your tank pressure get's very low - below intermediate pressure settings - your odin second stage will start free flowing in your mouth. If you're below 150 psi... I'm thinking it might be time to go up anyway... you think?

 

[DA Aquamaster]

With an upstream second stage design like the older Poseidon second stages, a higher IP means a tighter seal, unlike a regular downstream second stage that will freeflow with excessive IP. Conversely when the IP is low enough, an upstream second stage will no longer seat effectively and a freeflow can result.

An increase in IP as tank pressure decreases a characteristic of any unbalanced diaphragm first stage and was pretty commonly encountered in the past. Any downstream second stage will work fine on this type of first stage as long as the octo or second stage is tuned at a low tank pressure (normally around 300 psi) where maximum IP will occur. The breathing resistance will be slightly higher with a full tank but not to the point of being objectionable.

 

[rab]

The only thing that is weird about poseidons, is when your pressure is low - the Odin second stage won't seal... For fun some time kick on a tank just a little bit with a Jetstream Odin, and the second stage will be free flowing along... You have to crank on the valve to get the pressure up to get the second stage to stop free flowing... but just the odin - not your octo.

So the thing that happens is when your tank pressure get's very low - below intermediate pressure settings - your odin second stage will start free flowing in your mouth. If you're below 150 psi... I'm thinking it might be time to go up anyway... you think?

I thought this was the case given the normal behavior when relieving the pressure to remove the reg (Xstream) after the tank was off. Another ScubaBoarder had surmised that this was possible, but didn't back it up with evidence/experience.

-Rob