Dangerous lies?

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The only way I could imagine it might be true, is if repetitive smoking slowed one's circulation enough so that you actually used less oxygen overall. But that's a reach, and I have no evidence.

Not a good outcome, regardless of the reason.

- Bill
I never could understand the thinking behind the "smoking makes you use less air" theory, but to the best I could decipher it, they felt that people who smoke have adapted so they can get by with less oxygen, or something like that.
 
I guess the best three whoppers I've ever heard come from the dive industry, not from divers.

"Them J-valves will kill you, that's why we don't use them anymore."
Um, no, the USN, NOAA, and OSHA actually approve them as redundant air sources and REQUIRE them in some conditions. But the dive industry knows better. And DAN notes that somehow, even with pressure gauges, divers are still dying from "out of air" situations because they just forget to look at the gauge. The USN knows that even in black water diving, you don't need to see squat in order for the J "reminder" to work.

"You can't get a plus certification on your tank after it was made."
Um, no, the DOT says a + rating can be given forever, at every hydro, if the hydro shop knows what they are doing and the tank passes the test. But of course, that would mean "choices" and interrupt the assembly-line routine. And maybe, even require looking up numbers.

"You need a hydro and a VIP"
Um, no, again. The DOT says every hydro STARTS with a comprehensive VIP. If you got a hydro, you already got a VIP, there's no need for the dive shop to do a second one. When the dive shop says "Yeah, but they don't know how to do a SCUBA VIP" ask them, "So, the hydro shop is incompetent, but you used them anyway?"

There's enough FUD in the industry to go around, even if the divers remain speechless.
 
Ask them to blend you some 28% and stay with 1.4 (mod 132) or dive 1.6@32% (mod 132) or just get them to top up a used 32% tank with air and analyze it to see what you've got..

Well Duh, I'm a dumb a$$. I didn't even think to ask for a custom blend. Only dove Nitrox a few times and have just been used to being handed a cylinder of 32. No one has ever asked what blend I would like - but again, am new with Nitrox
 
Well Duh, I'm a dumb a$$. I didn't even think to ask for a custom blend. Only dove Nitrox a few times and have just been used to being handed a cylinder of 32. No one has ever asked what blend I would like - but again, am new with Nitrox

I would not say you are a dumb a$$, actually most places will NOT blend you a special blend unless they state that. Most places will bank whatever Nitrox seems to be the most popular for the area, if they have Nitrox at all. I still frequent a few shops that don't even do Nitrox.
 
First, understand that we don't have lots of experience, so no judgements please. So we are doing 4 days of diving next week. I bought a Nitrox package that covers all the dives. But I noticed that one of the dives is 130 fsw - a wreck. The MOD of Nitrox 32 according to my computer is 110. So, I am thinking that we will opt for air during this dive. Does this make sense? It seems like a no-brainer but looking to my more experienced forum members to confirm.

Well Duh, I'm a dumb a$$. I didn't even think to ask for a custom blend. Only dove Nitrox a few times and have just been used to being handed a cylinder of 32. No one has ever asked what blend I would like - but again, am new with Nitrox

I would not say you are a dumb a$$, actually most places will NOT blend you a special blend unless they state that. Most places will bank whatever Nitrox seems to be the most popular for the area, if they have Nitrox at all. I still frequent a few shops that don't even do Nitrox.
A lot depends upon the shop and how much control it has over things. If it is making its own mixes, they can take care of you easily. If they are getting standard fills from somewhere else, they might not be able to help you.

You do not need a specific mix for the dive you are planning; you just need to make sure you do not go beyond the mix's MOD. That gives you more options than you might think. THe shop has some options they might not realize, either.
  • If the wreck is advertised as 130 feet, that probably means 130 feet to the sand. You don't have to go to the sand. If it is a good sized wreck like the Spiegel Grove, you can have a great dive without going below 110 feet.
  • I dived out of a shop in Bali a few months ago. It filled its tanks out of sources--its bank of air or its bank of 32%. It sounds like you have only two choices, but that's not true. They can fill your tank say 80% full with 32% and then top it off with air. With a little math, they can give you any percentage you want. If you aren't particular, you can take anything in the range of 27- 30% and be perfectly happy.
 
With a little math, they can give you any percentage you want. If you aren't particular, you can take anything in the range of 27- 30% and be perfectly happy.

What he said.

With this calculator:

Nitrox Blending Calculator

I calculated that you can bleed a cylinder of EAN32 down to 1900 psi, then top it with air, to end with 3000 psi of EAN28.
 
It's been a while, but we have threads on ScubaBoard in which people insist it is true. There was a thread a couple of years ago about a team of pubic safety divers. Normally non-smokers, they smoked up a storm when they were diving on the theory that it made their air consumption better. That is lunacy. There is no physiological reason why it would be true, and there is a strong physiological reason why it would NOT be true.
unless it helped them relax and they misinterpreted the data-but eventually the alveoli might have the deciding vote
 
Well Duh, I'm a dumb a$$. I didn't even think to ask for a custom blend. Only dove Nitrox a few times and have just been used to being handed a cylinder of 32. No one has ever asked what blend I would like - but again, am new with Nitrox

I bet the operator provides gas appropriate for the dive. They would be foolish not to. I dove the Spiegel Grove in Feb with Rainbow Reef. They provided 30 for the dive. My max depth was 105 feet. There is no need to go to the sand.
 
https://www.shearwater.com/products/peregrine/

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