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Calculation of Trimix fills

4K views 35 replies 19 participants last post by  Air Guzzler 
#1 ·
How can i calculate the cost for a trimix fill for None Standard gas fills

I realise its cost per litre but how much He for each mix
twin 12's

Without using software as my phone is $h1t and i have to use my brain
 
#3 ·
my muppet way-


you have to change the figures for yourself-.


lets say a dive to 60 m.(7 bar)

max 02 of 1.2.
max n2 of 3.8(makes the sums easy) bit less than 40m end.

add them together gives 5.

so 2 bar must be helium.-this makes the 7 you need.


2 bar divided by 7 =.28

so 28% helium fill.

28% of 4800lts =1344lts

1344 lts x price per ltr.
 
#7 ·
Even simpler - go CCR and never think about the cost again !:D ;)

Saw the price of Geoff's twins 12's remix on Sunday for £55 and all the CCR divers winced liked they'd been the ones kicked in the knackers !!! :D :D

By contrast I used 25 bar of 17/45 and 40 bar O2 which it cost me about £3 (and 4 or 5 quid of lime)

G

.
 
#13 ·
It's an old topic, but I reckon at the time I went CCR, I was doing 50-60 dives pa in the 50-70m range.

Avg gas cost per dive was £45.

On the CCR, my avg costs were gas and lime of less than £10, so saving £35 per dive.

My unit and traning cost me £4,350 over 3 years (purchase £2,750, training £1,000, servicing/cells £600), so, easily broke even.

A huge benefit was logistics for a weekend or week away, I just didn't have to worry about driving a hour each way to get gas or any similar silliness.

On top of that, it's a much nicer say to dive IMO.

For me it made sense on all counts. If I were only doing a few deep dives each year then I could never have justified it on cost, but would still have been tempted (knowing what I know now) just for the convenience.

Juz
 
#21 ·
Ironically I used to have a ybod sold it last year and went back to oc. Do I regret it? Not one bit I'm much happier on oc, dive trips are much more enjoyable due to the fact I don't have to spend ages arsing around with the unit and wondering if it's going to breakdown. I'll no doubt get loads of grief from ccr divers but this is just my opinion.


Sent from my iPhone using Tapatalk
 
#22 ·
more enjoyable due to the fact I don't have to spend ages arsing around with the unit and wondering if it's going to breakdown.
How much time did you spend arsing around then ? I dont get it - prepping a CCR is a piece of p!$$ - just methodical, hardly takes ages (well unless you're a Mod 1 newbie :D :D )

I've got 400+ hours on my Vision and the head has been back once for 1 led on the HUD going down. Nicola the same time but had to have handset work done when she caught it between the slats on a dive bench and stood up !!) She just did the dive on her Shearwater 3 cell backup (brilliant narked at 90 product) Thats it - I know loads of others with very few if any problems but you only ever hear the bad experiences on t'interent I guess.

What sort of depths/ runtimes were / are you doing ?

G :)

.
 
#25 ·
I agree completely. Cant understand though why you would buy a CCR with only intention of using Air dil to depths OC covers really well for little / no hassle.

The thread has gone a bit off topic (dont they all :D ) My view is that CCR is the way to go for Helium cost / benefits etc as above detailed but save your money and stay OC if you dont intend to do the dives that warrant using one.

I still do the shallower c. 35-40 metre stuff CCR because I dont own any OC kit anymore and I like to keep a CCR mindset

G
 
#29 ·
Little something from 4 days diving in the 40m to 50m depths.

My gas bill £21 - including refilling a 7l bailout and an18/30 in 3.

My buddy on twin 10's and stage. He was using 50% and air for the shallower stuff where he could and then 20/30 and a stage of 80% for the deeper couple of dives.

His gas bill - £156.
 
#30 ·
You need to include the £30 of lime you got through.

Your "profit" margin probably comes to £100 for 4 dives then. A saving of £25 per dive. There are a lot of dives for £5K, more than most people manage before they end up buying a different unit and losing a load of money selling theirs...

Never discount all the other crap that comes with rebreather diving - all the extra bits here, modifications there, cells, spares, tools, time spent on maintenance - it doesn't break even for 40-50m diving. I found if you didn't hit a huge number of dives in a year, or did a lot of 60m+ diving, the numbers don't stack up against a big twinset and two stages.

Digs.
 
#32 · (Edited)
I don't know anyone that has lost more than a hundred quid or so on a unit. I sold my KISS for more than I paid for it.

40-50m is a big grey area for me, I'd rather dive OC but I also resent paying for mix. I got to the point that I couldn't justify buying a rebreather because I wasn't diving mix enough to merit it but then I realised I wasn't diving mix enough because I was OC.

30 quid of lime in 4 days? I never used 30quid of lime in a week of gas diving in the northern Isles last year.

I did a calc of how long it took me to pay for my rebreather on DIRX, I think it came to 6 months diving. That was including consumables i.e. cells & lime. I see people writing about what they've had to buy since going CCR, I've not bought anything that hasn't needed replaced anyway. Sure you can go mad and buy computers and wings and lights and all sorts of crap but water is water, nothing is different because you have a different box on your back. The same kit works fine.
 
#35 · (Edited)
im happy to see lot s of oc divers on tm, keep,s the price of gas cheap for ccr divers ,, do you think we would be getting cheap gas if there was no oc divers ,,
dive shops price the gas so oc dives can just about pay for it ,, no oc diver = alot more cost for the ccr diver ,, so lets not take the piss to much ..

i would not want to end up paying 20 quid for a 3L of o2 and 30 quid for a dill ... .. so long live the oc tm diver ,, and please keep telling your lds that there taking the piss ,,,, cos when they have maxed you guys out they will be after us ,,,
 
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