Cylinder advice.

[Lee Hurley]

Hi,
im looking to get my wife and i 2 cylinders, i think were settled on 12ltr tanks, (unless anyone has good advice/reasons why not ) upon looking closer at where i was going to buy ( not sure if i am allowed to post links ) i saw that for £5 more the cylinders were nitrox ready both were 232b.

sorry for whats possibly a dumb question but can i use the nitrox cylinders for just air, then id be sort of ok for when i go to nitrox?

or am i not making sense or have this completely wrong?

thanks
Lee.

[Nigel Hewitt]

sorry for whats possibly a dumb question but can i use the nitrox cylinders for just air, then id be sort of ok for when i go to nitrox?A cylinder becomes a 'nitrox cylinder' by being specially cleaned. Nothing magic.

Most cylinders come like that from the manufacturers but the shops don't bother with all the extra stickers or paperwork unless you actually want 'nitrox'. They might do the stickers free or they might charge a fiver.

Getting a cylinder re-cleaned and stickered will cost you about 20 quid so it's a good deal if you want it.

However a cylinder becomes not nitrox clean if you start filling it with unknown gas. Now I say unknown as most gas supplied is clean but not every gas source is tested and certified. Filling it with air is quite OK provided it is 'clean' air. ie: certified clean.

I'd go for it. Nitrox suits the sort of diving we do in the UK and keeping a cylinder in 'clean' status isn't hard. In fact most shops will just fill it as most of the cylinders they see are nitrox cylinders.

A nitrox course is half a day of lectures and a simple test. If no-stop times are getting restrictive, they do, go for it. Then if you want to use nitrox you can but you never have to. Nitrox just gives you longer no-stop times than air at the same depth.

[Dave (Simmo)]

Hi Lee,

i'm assuming the cylinders new.
If not, at least get two that are the same, many people move onto twin set diving you may well in the future, if you buy two cylinders which are balanced now it will save you with the bother of having to sort it out later.

Oh and in the future i wouldn't buy a 15. i started off thinking 12 is fine. Then i wanted to go a bit deeper so i bought a 15. Now as diving becomes more adventerous i'd like a twin set but i'm left with an old tall 12 which i cant easily match and a 15l O2 clean. So i'm going to have to speand a fair sum to move on.

Dave

[Hamish]

Hi Lee,

No question is dumb if you don't know the answer, but as for your question, purchasing nitrox clean cylinders means just that, they are already cleaned and suitable for nitrox fills. It is the second part of your premise that is slightly incorrect in as much as this.

If you decide not to use them for nitrox and just fill them with air there is no problem that I know of provided the air station has double filtering (most that I know of do). The problem would arise if you filled it at say an air bank supply which was replenshed by an older compressor which did not filter to the standards required by nitrox cylinders. You can of course buy filtering units that are positioned between the filling station and the cylinder but these are costly.

The bottom line is, if you are not going to be using nitrox for perhaps some time I would not bother with nitrox clean cylinders, if I remember correctly nitrox cylinders require certification every 12 months so if you do not use them for such you will be required to get them cleaned before use anyway.

If my information is out of date I'm sure one of the brighter boys will be along to put me right.

Regards

Hamish

[PeteM]

However a cylinder becomes not nitrox clean if you start filling it with unknown gas. Now I say unknown as most gas supplied is clean but not every gas source is tested and certified. Filling it with air is quite OK provided it is 'clean' air. ie: certified clean.

However be aware that some dive shops rip you off an extra 50p or quid to give you clean air - sort of acceptable if you are diving nitrox but not if you are not going to do the course for a while as you will still end up paying the £15-20 to get them recleaned anyway after a year.

[Lee Hurley]

all sounds good advice, looks like ill save the extra £5 then and go for the normal 12 fabers.
is it ok if i post where i found them? incase it helps someone looking for cyclinders, you guys are probably well ahead of me anyway hehe.

thanks again,
Lee.