Nitrox Common Mixes

[Lead_carrier]

By 'limits' I meant that the local SSI place here offers a nitrox cert that is limited to 32%. It has a through lab and test after the study work. But they also offer a 40% max cert if you include dives. Little more expensive and it is getting colder here. Not sure if this is standard everywhere (I haven't gotten the same answer twice when I call around), but I love this shop and their customer service.

My 2psi says that you might ought to look for a more above board dive shop, and for the record, I am an SSI instructor. SSI offers EANx40 which is the orginal EANx course that we have taught for years. No dive is required but they are optional. The EANx 32 card should serve you just fine but I still think they are a bunch of peckerwoods for playing that game.

As for the diving I do, if 32% is banked and it will handle my dive then I will gladly use it. According to the planned sites, I'll figure out my MOD at 11.4 ppo and base my mix on that. Then if the site isn't attainable I can do a shallower dive with no problem and even a SLIGHTLY deeper on that might make my ppo 1.5.

 

[conway400]

This has been very educational for me. Thanks all. And for the record - I am with you. I am not stupid and I do understand that the primary difference between the two course that they are offering (32 vs. 40) is to charge more money. I was bothered (the SSI shop and the local PADI shop did the same thing) that they said the course was just $75! But you may want to also pay the $50 for the lab, test, and cert card. Now why anyone call and not want the one price to get it all done...

 

[MXGratefulDiver]

This has been very educational for me. Thanks all. And for the record - I am with you. I am not stupid and I do understand that the primary difference between the two course that they are offering (32 vs. 40) is to charge more money. I was bothered (the SSI shop and the local PADI shop did the same thing) that they said the course was just $75! But you may want to also pay the $50 for the lab, test, and cert card. Now why anyone call and not want the one price to get it all done...

Lab? Test? Cert Card? ... they charge extra for that ???



... Bob (Grateful Diver)

 

[scubafanatic]

Simple. Choose a standard nitrox gas that matches the deepest MOD you'd be willing to dive anyway. For me, that works out to 32%. Past 110', I'd want helium locally anyway. 32% covers *any* dive depth I'd be willing to do on nitrox (1-110').

If I bring 40% for a dive planned to 70', but that's blown out and we end up at a site in 100', I'm screwed (been there, done that once, never again).

There are also other benefits to a standard gas choice: teammates are all on the same gas (so similarly NDL-limited), familiarity with allowable NDLs at various depths / profiles, not having to remix for future trips, ease of blending, ease of gas acquisition, etc.

Helium past 110' ? Seriously ? You're not gonna find Heluim in 99.999999 % of the world's dive sites/ops anyway or be able to afford it either......

 

[Rainer]

Strange, I've so far been able to dive it in 100% of the dive sites I've wanted to.

Helium past 110' ? Seriously ? You're not gonna find Heluim in 99.999999 % of the world's dive sites/ops anyway or be able to afford it either......

 

[vladimir]

Strange, I've so far been able to dive it in 100% of the dive sites I've wanted to.

Presumably with the aid of a loan shark, since there's no way you're able to afford it.

 

[MXGratefulDiver]

Helium past 110' ? Seriously ? You're not gonna find Heluim in 99.999999 % of the world's dive sites/ops anyway or be able to afford it either......

Presumably with the aid of a loan shark, since there's no way you're able to afford it.

Well ... he did say "locally" ... and for him that means southern California. Helium's probably a lot less available and more expensive where you live than where he lives. I could easily afford to use helium below 110' if I chose to (my personal cut-off's 120') ... and I don't make a rich man's salary. On the other hand, it's pretty readily available and affordable where I live too ...

... Bob (Grateful Diver)

 

[vladimir]

That was subtle sarcasm on my part.

I have no idea what Rainer can afford; I was just ribbing scubafanatic a little for presuming to know. (Maybe he's Rainer's accountant? )

 

[MXGratefulDiver]

Generally speaking, a trimix fill in my 119's would run me somewhere between $5-$10 more than the percentage of helium in the mix. For example ... 25/25 is about $30 ... 18/45 is about $55. Considering the other costs associated with doing those dives, if I can't afford the mix I shouldn't be contemplating going that deep ...

... Bob (Grateful Diver)

 

[Jax]

There are also other benefits to a standard gas choice: teammates are all on the same gas (so similarly NDL-limited), familiarity with allowable NDLs at various depths / profiles, not having to remix for future trips, ease of blending, ease of gas acquisition, etc.

Pardon me for using your post . . . I hear people saying "common gas = common NDLs", but that only works in a DIR-ish scenario. If divers are all on the same mix (like Bonaire), and everyone has different computers, and some are set to more conservative levels . . . that doesn't ring true, then.

There are underlying unspoken premise in those thoughts.