I suspect that this question is like asking what is the best light for caving and that it may sound a little naive but;
Any tips on what type of regulators are best for cave diving?

I too asked this question very recently to some experienced cave divers and they all came back and said :

Poseidon cyklon 5000


Stu.

Poseidon regs are the best because (apparently) other regs can go into free flow "mode" in the cold water found in caves.

Poseidon Cyclon 300 regs (as opposed to 5000s) are better for British cave diving, with a few reservations. Not generally available new any more but still crop up S/H at good prices. They're out of fashion because they (just) fail the ANSTI 50 metre test, which has very little relevance to most UK cave diving. These regs are the standard workhorse; some CDG members have been regularly using these (i.e. the same actual regs) for >30 years because nowt better has appeared.

There are many other regs which can be used perfectly well of course. But the Cyclon 300 has been the standard regulator used on many of British cave diving's finest explorations and achievements.

Look on the thread archives of the CDG website message board and you'll see quite a lot of very useful discussions there.

Whatever reg you end up with ( new or S/H ), make sure the connection to the bottle is DIN screw.

pitlamp said:

Look on the thread archives of the CDG website message board and you'll see quite a lot of very useful discussions there.

Click to expand...

Cheers, I have found some good threads on the subject in one JC agrees with you fully.

What is the difference between Cyklon 300's & Cyklon 5000's?
I ask as 5000's seem a lot easier to get hold of.

Mike W said:

Whatever reg you end up with ( new or S/H ), make sure the connection to the bottle is DIN screw.

Click to expand...

Understood.

Nooooo: don't touch the cyclon 5000. Got four of the buggers, had them for about a decade, and the only good thing about them is that they're easy to service. Quite handy as when I was diving a lot of grotty sumps I'd have to strip them down three times a year. Two disadvantages with the cyclon 300: they're like rocking horse poo and they can be a bit tricky to service (tend to damage the seat when you try to remove it).
(300 refers to the old, unbalanced first stage-the bit that attaches to the bottle; the 5000 is a more modern, balanced first stage). Real shame about the 5000 is that they're very nice bits of kit but they're too sensitive to survive proper caving. In my opinion, obviously. And most other people who've ever felt the need to twat their regs with a bolting hammer when they're on the wrong side of a sump!
One idea that the manufacturers don't like (but I swear by) is mix and match. I use cyclon 2nd stages (bits that go in your gob) attached to the most basic 1st stage money can buy (in my case a Scubapro something or other). You need to tweak the regs a bit but there are plenty of helpful types out there who could help. Seriously, though, if you're just thinking about short, simple sumps then just go for anything that's cheap, simple, and reliable. To get your shiny 5000 serviced in a dive shop you're looking at a ridiculous price of about £60 plus. Really not worth it. Hope this helps. If nothing else it'll make you realise that every diver out there has a different opinion...
By the way, is "Mike W" the Mike W that I'm thinking of? Hope you're coming to the BCRA do?
Joel

Disagree with Joel - 5000's are not as easy to service as 300's. The other main difference is that 300s are much less chunky in the 1st stage so are more easily packed into a smaller container for long difficult carries. They also weigh less than 5000's. 5000's are more finnicky and less good as a UK workhorse reg. 5000's definitely breathe easier at depth but the difference isn't really important unless you regularly visit the wrong side of -50 or -60 metres. It's horses for courses really.

But ignore what we say - try loads of different ones and buy the ones YOU like best. Just avoid those dreadful Oceanic "shower head" regs!

Thanks for all your advice guys.
I have managed to get hold of a Cyklon300 and will have it serviced. Also I have purchased an Apex similar to the one I have been borrowing, seems simple, robust and I like the feel of it.

When I was diving I used various regulators including Apex ST5000 and several Scubapro models. However, my favourite valve was a Poseidon with a Jetstream second stage and the simpler unbalanced diapragm first stage (as found on the old Cyklon 300). It is very easy to service the Jestream second stage (much easier than the Cyklon) and I found the first stage very reliable - only once did I have to strip it down.

I found that the Jetstream was less sensitive to variations in interstage pressure than many other models (either caused by bad tuning or another first-stage problem such as dirt or ice causing a slight malfunction). This was partly due to the fact that it has an adjustment button which can be used to adjust the sensitivity. With my old Apex valves it seemed impossible to get a good compromise between an easy breathe and minimising the risk of a free-flow. I used to opt for a stiff breathe, but it wasn't very comfortable.

The Jestream is pretty robust too. The one criticism is that it is very bulky, which makes it harder to pack into a small container for transport underground.

All this is history....since I don't dive anymore!

Mark

i havent done much cave diving in this country but have done a lot of deep diving in very cold water and the only reg i would use is an apex tx40. they dont freeflow and are easy to get hold of. i find the poseidon jetstream is just awful and the cyklon blow the high pressure seat for fun. i have dived on tx40s for years now and have never had a problem.