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I am looking at getting a stage cylinder to use for accelerated deco (yet to do a course yet but one planned in the pipeline!) I have been looking into getting an ali 7 but I have just been offered an ali 12 at a pretty good price... So a newbie to diving with stages is it worth a punt for the 12 or go for a 7?

My diving is in the 35m range...
 

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id go for the 7 my self , ali80/ 11L are big lumps ,, id not bother with them till im hitting 50m plus

if your diving a twinset and just the one deco gas ,, a 7l is more gas than you will need ,, even if your using a pisspoor 50% for deco ..
 

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Yup, 7 is plenty big. I'd even consider an al40. Sits much nicer in the water, light as a feather and a lot slimmer than the 7.

I have both and unless I need the extra volume of gas, will take the 40 for preference every time!
 

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max depth of 35m twin set 40 min bottom , id say two just on a 50% 3 on 80% and maybe 5 on o2 ,, back up on back gas if you run low on deco ,, thats why i say 40mins bottom (thats off the top of me head )
with a half right sac ,

cant say about a 40, as iv never used one ..
 

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Well I have an Ali 80 and take it on most dives. I don't find it a pig an love knowing I have loads of deco gas.

C
 

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I recently bought a Luxfer 7l 200 bar ali for the type of diving you're talking about, I've never liked using the luxfer 232 bar 7s, I've always felt they were in the way, but i'm quite happy with the one I have now, then again I do have it rigged differently to how I had the 232 bar one, and the 200 bar one does float when empty even with a reg on in fresh water, I don't know how positive it is but it's something to bear in mind. I've tried an 80 a couple of times and they are very nice in the water, I preferred them to the 232 bar 7, but a pain out of the water compared to a 200 bar 7.
 

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I use an ali 40 which is good for two deco dives with 50% in for me.

Lovely in the water and out of it.

I guess the obvious answer is to figure out your sac and how many dives you want it to last for then go from there
 

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For me it's ali 40's up to 50m then ali 80's for deeper.
Both are very good in the water but 80's are a pig out
of the water. Then again I'm a short ass.
 

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I like the 40 for 100%. It's really nice in the water.

The 80 is a beast. Loads of gas but either heavy or floaty which tends to hurt my neck if I'm not careful. You can stick 2 under your left arm happily but you'll know they're there.

A 7l is great - slightly bigger than the 40 but no real bother and has rather more gas. Definitely the best compromise IMO.
 

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I like the 40 for 100%. It's really nice in the water.

The 80 is a beast. Loads of gas but either heavy or floaty which tends to hurt my neck if I'm not careful. You can stick 2 under your left arm happily but you'll know they're there.

A 7l is great - slightly bigger than the 40 but no real bother and has rather more gas. Definitely the best compromise IMO.
Or get the 40 for now then get a 7 later if and when two stages our one larger stage is needed
 

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big, floaty, 200 bar id stay well a way from ,,

260bar:zip: steel 7 cheap as all the smart money lol want , ali ,, fook knows why ,, but hay o ,,

given you said your diving is max 35m at the mo ,, your going to/want to dive one deco ,

the max you would get bottom time and deco is set by what you have on your back ie in the twinset ,
and your RMV .. if we say 20lpm norm and 15lpm deco , max you can do on THE TWINSET, is say 40min bottom .. ball park numbers ,,
now thats your dive plan ,,
now pick a deco gas lets say o2 , your going to need 400L (500L of 80% or 800L of the pisspoor 50%)

so looking at them deco numbers even with a pisspoor 50% you have twice what you need ,,

dont bother with all the bollox ,, a one cylinder deco dive is a TWINSET DIVE WITH YOUR DECO CUT SHORT , WITH WHAT EVER SHITE YOU WANT TO PUT IN WHAT EVEN TIN ,,

your back gas is what matters as that,s the gas your going to bail out to when your only deco TIN dont give you the gas you need ,,

the cylinder is not the problem to be solved ,, (get what ever you like ,test a few and pick one)

just my 2p worth ,,

ps tham numbers are air and o2 ,, you can fanny about with all the nitrox as much as you like get your self 10mins more bottom time ,, but your backgas wont get you home , ( backgas still has to get you home and do the deco .. on a one gas deco dive) thats why you see the big ali80 cos no back gas to get home and the diver now has to hit a pisspoor gas deep ,, , cos his back gas now wont do the job ,,

Need twice as much GAS cos you now have to buddy dive ,, as you know if the deep deco gas was to stop working , your only way out is what,s in your buddys deep deco gas ,, ffs its bail gas ,, not deco gas , lol

go read what a deco gas is / pp2 ,, look at what 50% ppo2 is at 9m . i say 9m as thats were your 35m dive will put you for the first real stops ,, for get them one min deep stops , look were your deco stops starts , and plan the / YOUR deco gas ppo2 for that ,,
 

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The 12L or 80 will allow you do 4 deco dives.

Put in an 80% mix and get 2 dives out of it. When you are down to bar top off with air to 200 bar and you have a 50% mix allowing you do another 2 dives before you get to 100 bar again.

I think that a cylinder that size allows great flexibility for weekends away where access to o2 is an issue
 

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I am looking at getting a stage cylinder to use for accelerated deco (yet to do a course yet but one planned in the pipeline!) I have been looking into getting an ali 7 but I have just been offered an ali 12 at a pretty good price... So a newbie to diving with stages is it worth a punt for the 12 or go for a 7?

My diving is in the 35m range...
What do you have on your back?

You're not going to get much acceleration at 35m depth - 35m/40mins is 3 minutes different if you use 30% bottom mix and a 36% deco gas, 14 minutes if you take O2. Main thing you're getting is more volume.

Without a deco mix you need 4690L - assuming you're in twin 12's - 195 bar (so not doable, RMV=20).

With the O2 you need 3848L (160 bar, doable) and 294L O2 (42 bar, 7L or 98 bar, 3L).

7L would be my choice here and then you can add another one later if you start meddling with gas.

Matt.
 

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The cylinder you have been offered what is its water capacity? people on here have assumed its an ally 80 in which case its water capacity will be 11.1 litres if its water capacity is 12 litres it will be an old cylinder that will be a right beast to use. what sort of valve does it have you really want a din valve.

I suggest you see if you can borrow some different size cylinders and see what suits you rather than listen to I have size x so it must be the best type advice.

Graham.
 

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The 12L or 80 will allow you do 4 deco dives.

Put in an 80% mix and get 2 dives out of it. When you are down to bar top off with air to 200 bar and you have a 50% mix allowing you do another 2 dives before you get to 100 bar again.

I think that a cylinder that size allows great flexibility for weekends away where access to o2 is an issue
cant see my self at 35m draging round 2000L of gas in a large cylinder , that is uslees to me till i get back to 9m, then use 500l of said gas ,, for my deco

each to his own ,,

im off done with this one,
 

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A 200bar Ali 7ltr would be my choice.... I didn't like the 232bar Ali 7ltr... I found it behaved just like a steel 7ltr, hung down and felt heavy in the water. The 200bar tanks are brilliant, and I hardley notice they are there. If it is a 12ltr you've been offered it may not be an Ali80 but an old MDE Ali... check how old it is..
Best advice is borrow a couple and try them out.. good luck, Its a very personal choice and no real right or wrong answer, as long as you have enough gas of course.
 

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cant see my self at 35m draging round 2000L of gas in a large cylinder , that is uslees to me till i get back to 9m, then use 500l of said gas ,, for my deco

each to his own ,,

im off done with this one,
You can't have too much gas on the bottom, you never know what you might find ;)
 

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You can't have too much gas on the bottom, you never know what you might find ;)
lol yep 2000l of 80% would be good for blowing the swag bag if your sending a Sherman tank up,
no other use for it at 35m,:shade: but your righ 1500l for the sherman and 500l for the deco ,, sorted ,,

right im off once again lol

your a bad man, ken


edit that only 1000l for the sherman ,, as my buddy will need 500l also ,, he ant got the back gas to finnish his dive, and hes lost his reg off his 2000l cylinder ,,

sorry ill need to edit once again

think ill pass on the sherman as im not sure 500l will do my fat buddy as his eyeball s are looking rather large ,, lol
 
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