Love my Poseidon, but I think it's time to let it go. What's next?

[Archaeological diver]

Hello all. I have been doing deep air diving for a few decades, and have loved my Poseidon Jetstream/Odin (and have also been using a Scubapro MK15 with a Dive Rite second stage on the other cylinder, with no actual love but reliable performance). My problems are two:

1. The Poseidon seems to need an extensive rebuild after every trip, and in recent years there's no shop in Austin that services Poseidon, so I have to ship it to Houston every time, wait weeks, and pay through the nose. I've done this for several years, but I'm starting to feel a bit silly doing it to keep a 25-year-old reg going, and I am about to increase the frequency of my trips as well, so this regimen seems unsustainable.

2. I haven't kept up with regulators on the market in a long time, so I don't know what I should consider as a replacement, or actually two replacements, since the MK15 blew apart when I pressurized it yesterday, and it's 25 years old as well. I started poking around today, and kind of like the Apeks Tek 3s, but I haven't yet found much info online about my main concern: the need for and availability of maintenance. (I'm not very mechanically inclined, and don't care to do it myself, and it seems like most commentators on tech diving regs do maintenance themselves and/or dive in fresh water mostly, and I dive mostly in salt water.)

So my questions for those wiser, more mechanical and more current on regs are:

1. Why does my Poseidon's HP seat seem to fail every time I pull it out to test it before a trip (no matter how meticulously I rinse it after every dive)? I love the sound of it under water, the performance at 60 m, and, I'll admit, the image of it, but it fails EVERY time I pull it out to test it. I assume there is something about the design that makes it prone to corrosion (?).

2. Assuming my maintenance problem with the Poseidon cannot be solved, what should I get to replace my old regs? I need something that breathes well in deep water, handles salt water with a post dive fresh water rinse/soaking without corroding before the next adventure, and, when necessary, can be serviced in Austin. (There is a shop here that sells Apeks, and of course more mainstream brands are easily found here.) (Do modern Poseidons require less maintenance, perform like the Odin, and provide that old rumble? I couldn't buy those here, but if they only needed annual maintenance...)

I dive in Italy for 4-12 weeks every summer, and in the Caribbean for short trips at other times, so I am trying to factor that in for maintenance considerations. (For years while I was working in Turkey there was an old Swedish guy in Bodrum who would rebuild my Poseidon, but he's gone now.)

Thanks for any advice. Leaving for Italy soon.

 

[rsingler]

Your issue seems unusual. Poseidon is a superb design, though when you say "25-year-old" reg, I'm trying to imagine which model you have. If it's the old 300 short stubby first stage, then yes, it's time to retire that one. But if it's the 2950/2960 with truncated cones on both ends, I can't imagine why this is happening so recurringly.

In any case, it's probably not worth going through a discussion on how you could prevent this, and there indeed have been high pressure seat issues with an entire machine that Poseidon used to use to fabricate them (#4 on the seat stamp, as I recall). But that could be a long discussion.

What may be more interesting to you will be that the new XStream is UNBELIEVABLE. The key is that the HP seat sealing surface has been shifted from a knife-edge to an entire bowl. There is a synthetic ruby ball (e.g., zero corrosion) that plops into place in a cup-shaped floating seat that moves with varying tank pressure. It's the most ingenious diaphragm design on the market.

Xstream_cut

• rsingler
• Nov 9, 2017

Xstream

• rsingler
• Nov 9, 2017

So if you love your Jetstream, consider this upgrade.
The new Jetstream 2nd stage is also an improvement, with a shorter stem on the servo valve.
And it's tested to the 650 foot range. The 1st stage diaphragm is soft and pliable and bonded to a tough fabric that gives it a long lifetime.

PM me, if you'd like to chat. I can turn your gear around in less than "a few weeks", and while Poseidon parts are more expensive, I'm a very good (and approved) Poseidon repair guy.

Don't give up, just yet. If you'd like to give your existing gear one more try, let me take a look at it.
I'm sure loads of other SB'ers will chime in with alternatives. And I do love my Atomics. But it's nice to see Poseidon love every once in awhile.

Cheers!
Rob

 

[Caveeagle]

I suspect they are not being serviced by somebody who knows what they are doing.

The Jet/Odin 1st stage has a plastic seat with a steel cone shaped piston(orafice?)

In the DEMA Oct '17 tech class, they said any seat with a 3 or 4 should not be used, and they would replace them.

You can also have an issue with imoerfwctions on the steel cone surface. Another poster here says they can be buffed out with a micro mesh cloth, but I have not tried that personally.

Another Poseidon tech that I trust says he just replaces the cone/piston. Because that just aren't that expensive.

I halve not bought an Xstream yet, but they are very nice! I got to rebuild a set, and I was very impressed with the design.

 

[rsingler]

Now for a diagnostic discussion.
If it's always a HP seat issue, and we're talking a diaphragm reg, a little alarm bell goes off. Salt water shouldn't matter. Corrosion shouldn't be an issue. The inside of the reg is dry. Who cares how crusty the outside gets? The inside is dry, pure air.

Unless it isn't.

I see as a recurring repair issue for Poseidon a line of pitting in the HP cone that seals against the seat:

I think that high velocity air comes straight from the tank thru the filter and impacts the cone here. IF a diver is a little sloppy about keeping the sintered filter dry, then salt crystallizes there, and can get blown into the cone like a sand blaster. Alternatively, if the air supplied has dust, either from aluminum oxide corrosion in the tank, or iron oxide dust in a steel tank, the same thing can happen.
In other words, this design is susceptible to slightly dusty air.
But otherwise, corrosion shouldn't be an issue. If your sintered filter isn't slightly green from verdigris corrosion, and your tank is absolutely clean inside, and you trust the filtration of your source air, and you don't have HP seat #4, then I have no idea why this is happening to you.
But I sure do polish a lot of Poseidon cones (they call it the "piston"), rather than charge my customer for a new one.

 

[rsingler]

Lol. @Caveeagle beat me to it while I was writing!

Yeah, I DO restore the piston with Micromesh:

 

[Caveeagle]

Can you describe how you restore that piston/cone surface? Do you spin it somehow? Or just by hand?

 

[rsingler]

Can you describe how you restore that piston/cone surface? Do you spin it somehow? Or just by hand?

PM sent

 

[diversteve]

I've access to an old Jetstream also - no issues with it. Closer to 35 years old and I believe it's s 2950 but not sure.

As a replacement with the same or better breathing - I'm currently diving Atomics - currently a T2 but I've also owned a B1 and Z1. They are just the sweetest breathers without the "rush" of the Poseidon. www.atomicaquatics.com

The whole line breathes the same - just different materials used at different price points. If there's a gotcha it's that due to the Seat Saver Orifice water can travel down the hose into the 1st stage when non-pressurized. So to rinse mine, I keep the hose higher than the stages - usually hanging it on the faucet works well. You wouldn't want one for a pony for that reason.

Of course my T2 - being all Titanium - it doesn't matter much. I've also had it upended off the back of a truck with the tank on, landed on a rock right on the yoke. Picked it up,dusted it off and dove it the rest of the week. You can't tell.

All their models have 2 year/300 dive recommended service intervals.

 

[scubafanatic]

I own several Jetstreams (sold off a couple like 10 yrs ago, still have a few left in reserve) and I liked them, plus they look COOL! However, Poseidon has had parts supplier issues in the past, plus they are a bit 'weird' internally (the 2nd stages), parts are expensive, and most reg techs have little clue how to overhaul or tune them, so I haven't dove mine in probably a decade or more. I also own 10 or so Atomics (8 or 9 of them being various T2's or T3's) and the Atomics are the ones I bring on dive trips, as they look (and are) quality and high performance, reliable like a Toyota Camry, you never question if it's going to work or misbehave, they just plain work and I don't have to worry about them!

 

[Caveeagle]

Of course my T2 - being all Titanium - it doesn't matter much. I've also had it upended off the back of a truck with the tank on, landed on a rock right on the yoke. Picked it up,dusted it off and dove it the rest of the week. You can't tell.

Just make sure you don't use that titanium reg with O2 or any rich nitrox mixes!

I own several Jetstreams (sold off a couple like 10 yrs ago, still have a few left in reserve) and I liked them, plus they look COOL! However, Poseidon has had parts supplier issues in the past, plus they are a bit 'weird' internally (the 2nd stages), parts are expensive, and most reg techs have little clue how to overhaul or tune them, so I haven't dove mine in probably a decade or more. I also own 10 or so Atomics (8 or 9 of them being various T2's or T3's) and the Atomics are the ones I bring on dive trips, as they look (and are) quality and high performance, reliable like a Toyota Camry, you never question if it's going to work or misbehave, they just plain work and I don't have to worry about them!

Parts are now easier to get than most of the big names like SP and AL.

I really don't understand why people have trouble with the 2nd stages. Jetstreams are much simpler to tear down and assemble than traditional downstream, balanced 2nd stages. I get that they are different. ..maybe that's why people avoid them. I started out diving with a Jet/Odin combination, so I find them very straight foreward and easy to understand.

I also find a few popular myths being perpetuated by those either unfamiliar with the brand, or just biased against them.
I.e.
Myth A: "All Poseidon regs use an abnormally high IP, and can't be mixed with other 2nd stages"
Reality: 0nly the Cyklon 2nd stages require higher IP (~165) and yes, that's higher than most 2nd stages are happy with. Proper IP for Jet/Xstreams is around 135, which is right where most other traditional 2nd stages belong.

Myth B: "poseidons are the only regs that will fail off, and lock out gas supply"

Reality: Jet/Xstream 2nd stages are both servo assisted upstream designs could be closed by pressure from runaway IP. That's why all early poseidon jetstreams had the OPV built into the LP hose. And after ~1991, they had an OPV built into the 1st stage housing. Mixing up an early 1st stage with a non Poseidon hose+adapter, and eliminating the OPV protection is where the risk exists. *Don't be stupid, and go swapping around reg parts if you don't know what you are doing.

Also, the only "no gas failure" I have ever witnessed was NOT with a Poseidon reg. It was a traditional design reg my wife was using, that one time we decided to use rental gear on a trip. Once we surfaced and reported the incident, the shop claimed "that's impossible, ..you must have done something wrong..etc". Shop owner hooked it up to a tank and the found out... "awe sh1t.... I guess it is possible".