I was wondering what the difference is between the Xtreme, Jetstream, and Cyklon?
Are there any new Poseidon reg models that are still upstream valves?
Why is the Cyklon cheaper than the other two?
Is it worth it to get the metal Cyklon?
What is a Cyklon 5000 as opposed to a regular Cyklon?
Are they hard to work on?
Can a diver get parts on their own through contraband sources easily enough?
I heard they're unbelievably smooth and great breathers, is that true?
How bullet proof are they?
1. Xstream and Jetstream are pilot assisted, semi-upstream designs, functionally identical for the regulator internals.
Cyklon is standard downstream design
2. see above, the Xstream and Jetstream require OPV's on either the hose or the first stage to prevent hose failures, require a certain IP to stop freeflowing *you hear a big whoosh when you pressurize them*, but at high enough IP, will start to leak.
3. The Cyklon is almost 60 years old, Jetstream is only about 30, Xstream about 15 *don't quote me on years*, the Cyklon also has a lot less parts in the second stage, and now it uses a very old first stage design vs the MK3 in the Jetstream/Xstream, and the MK3 is a brilliant first stage
4. Cyklon 5000 is plastic housing, Cyklon 300 is metal
5. no, but you need a vice to get the retaining ring back in the hockey puck of the Cyklon, and ideally a pair of custom forceps to adjust the Jetstream/Xstream. The forceps are available for about $25 from Northeast Scuba Supply. On the older first stages, like the ones coming with the Cyklons, you need a 27mm wrench that has been ground down to get the top caps off. Other than that it is standard allen keys and that's about it.
6. no need for contraband, they are freely available. DRiS has all of the parts if you call for them, DGX has them on their website
7. The Cyklon set the gold standard but requires a very high IP 165 vs 135 of standard regulators, and the Jetstream/Xstream work on a quite low IP of 125 or less. The cracking pressure of the Jetstream/Xstream is higher than most other regulators, but WoB is effortless. They all have a very violent purge though.
8. Ask the sump divers in the UK, the metal Cyklons are still being used over there for their durability, and are more durable than any second stage on the market. I dive Jetstreams personally which are quite robust as well but can't be cleaned as easily if you're muck diving. The Xstreams are the least durable of the bunch, but are also the smallest/lightest, and are on par with any other second stage for durability.
They all are non-directional which is nice for sidemount/stage/deco bottles, unlike the Apeks XTX which require parts to be reversed, you can simply flip them upside-down. Also nice for OOA situations where instead of creating an S between you and the OOA diver, you can flip the second stage up-side-down and it is good for an extra foot or so of hose vs. a normal regulator in this situation. Also allows you to swim next to each other without the hose having to make a 180* bend, very convenient. They breathe best when the diaphragm is down, but when the diaphragm is straight up they get a bit stiff. Won't leak nearly as bad as normal regulators when inverted though. The Jetstream has a dive-predive switch which raises the diaphragm off of the servo valve which is great for DPV/High current use to prevent freeflows, the other two do not, but it is also significantly larger, so pros and cons.
I love my Jetstreams and couldn't imagine using any other reg. My buddy says he would rather drown than breathe off of them because he likes his regs to breathe for him. His Hog's are set up so where if he loosens the pressure on his lips, it will start freeflowing. None of the Poseidons will do that, and I greatly appreciate it, he hates it.
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