Looking for thoughts that people had for selection of 2nd stages. I have Posidon Jetstreams on my twins. I like the 1st stages but would like to team them up with second stages that have a lower breathing effort.
Recommendations for 2nd stages
- Thread starter gdive
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BigboyDan
Guest
Howdy from Austin,
I use the Atomic M1 for open water (I DM near rigs, Flower Gardens, Stetson, etc.) - easiest breather that I've ever used. Shallow inland, I use the Zeagle Flathead with twins.
What's your diving profile?
(By the way, Keibler at Ocean Ventures in Houston runs the best rec-tek shop in the country, give him a call.)
http://oceanicventures.com/index.htm
I use the Atomic M1 for open water (I DM near rigs, Flower Gardens, Stetson, etc.) - easiest breather that I've ever used. Shallow inland, I use the Zeagle Flathead with twins.
What's your diving profile?
(By the way, Keibler at Ocean Ventures in Houston runs the best rec-tek shop in the country, give him a call.)
http://oceanicventures.com/index.htm
gdive:
Your 2ndstages sound like they need to be serviced and tuned properly. The Jetstream / Odin 2nd stage is a great delivery system for high volumes of gas. They are not "smooth" at first use but once you get them tuned right they are very easy to crack and deliver gas when you want it. The breathing effort on those is next to zero when set up right.
If you dont have a good technican who has worked on them a lot there is no way they will tune up right. They require a flow bench with dual gas supplies to set them properly.
Regards,
rescuediver009
Contributor
I am not 100% but am pretty sure that if you want to keep those first stages, you are limited to the poseidon range. As they are upstream regs, the intermediate pressure increases as the tank pressure drops (would cause other regs to trickle). The servo assisted design (poseidon, oceanic omega and zeta) will work on these as opposed to all the rest which are either balanced or unbalanced demand levers. Hope I didn't lose you.
The Poseiden first stages will work with some other second stages. Poseidon uses an upstream second stage design, but that just affects what happens when there is a failure resulting in an excessively high IP - the upstream second stage will not freeflow like a downstream second stage and some other method of overpressure relief must be used, usually with an OPV in the hose or on the first stage.
With an unbalanced diaphragm first stage design, the intermediate pressure will increase as tank pressure drops but this is not a problem with a balanced second stage, particularly if the cracking effort is adjusted at low tank pressure and maximum IP.
I have heard that Poseiden uses a higher than normal IP on some models but this is again not always a problem, as most balanced SP second stages for example can handle operating IP's of up to 190 psi.
With an unbalanced diaphragm first stage design, the intermediate pressure will increase as tank pressure drops but this is not a problem with a balanced second stage, particularly if the cracking effort is adjusted at low tank pressure and maximum IP.
I have heard that Poseiden uses a higher than normal IP on some models but this is again not always a problem, as most balanced SP second stages for example can handle operating IP's of up to 190 psi.
The jetstream 1st stage is outstanding. It is a balanced 1st stage with a servo boost. It has an IP range that can run from 100 psi - 300 psi for a variety of purposes. When we used them with the Kirby Morgan 2nd stages we would have the factory set the IP on the jetstream at 130 psi. When they are used with the Jetstream 2nd stage they are set at 152 ip.
The great part about the Jetstream 1st stage is the 15psi IP swing. Above 2000 psi supply pressure the unit stays at the set ip (eg 130 psi) as the supply pressure drops below 2000 psi the IP increases a little bit each time allowing the 1st stage to deliver the gas you need regardless of supply pressure. at 500 psi it has increased the IP by 15 PSI.
Aqualung and APEKs use this technology as well in their ATX and Legend series regulators calling it overbalanced ......
works well
jds
The great part about the Jetstream 1st stage is the 15psi IP swing. Above 2000 psi supply pressure the unit stays at the set ip (eg 130 psi) as the supply pressure drops below 2000 psi the IP increases a little bit each time allowing the 1st stage to deliver the gas you need regardless of supply pressure. at 500 psi it has increased the IP by 15 PSI.
Aqualung and APEKs use this technology as well in their ATX and Legend series regulators calling it overbalanced ......
works well
jds
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