Thanks for the great information. I believe the IP may be too high as the dive shop I bought the reg from wasn't Poseidon trained, but I am not comfortable checking it out. I was concerned the 300 octopus was holding back the performance of the 5000. It hasn't been serviced yet, but has only around 50 dives on it. It was usually the 300 free flowing, particularly when I went in the water, or it got turned a certain way. The 5000 only went off once or twice. Thanks for the info on the service shops, it was Mario in Toronto who said he could do it but with his shop only running part hours, I couldn't guarantee it getting there in his open time frame , and he is three hours from me.Too bad about your difficulties; those regulators are quite simple to maintain and last forever. I, too started out with the Cyklon 300. Many, in the States, who don't work on their own gear, routinely ship their regulators to different cities or out of state for overhauls.
Out of curiosity, does the Cyklon simply free-flow, when pressurized; or when the purge is used? Are you comfortable enough with your gear to check the regulator's IP? It could be a very simple fix, with a flat-headed screwdriver or dental probe; or one which will require an overhaul. When was the last time that it was serviced, if at all?
Below, is a section of the manual, where the second stage is adjusted, through the mouthpiece, by rotating an either white or black-colored ejector sleeve. It may just be a matter of decreasing its sensitivity a bit, since the Cyklon is usually set close to a free-flow. I adjust mine in that fashion and futz with it from time to time, if it becomes a bit too touchy.
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Here are also some resources for Poseidon, in Canada (you're in Ontario, eh?) and a copy of the service manual for you to examine . . .
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