down4fun
Contributor
Heart a lot about Trimix lately. I'm always interested in learning new things about diving. Can somebody explain me what are the advantages of diving with Trimix?
Air is 21% oxygen and the rest Nitrogen (some tiny percentages of other stuff but for this conversation o2 and N2). In recreational depths N2 becomes a limiting factor to your NDL's So the next step then is to reduce the nitrogen, this can be done in shallower depths by adding more O2, hence nitrox. Increase the O2 decrease the N2. But as you go deeper O2 itself becomes toxic. Also N2 is responsible for narcosis, so now you have to decrease the N2 for narcosis and the O2 for toxicity. Helium has become the norm for this third ingredient. It is an inert gas, meaning it doesn't it isn't metabolized or used by the body making it the best answer (so far). Helium is absorbed into you tissues faster than the other gases and so slowly ascending and being able to hold stops in order to off gas the helium at the correct rate is very important.
Most people have no idea how narc'd they are doing regular recreational dives, especially beyond 100 feet. As an AOW diver using nitrox on the deeper dives there would be parts of the dive I didn't remember until some one described it. That was narcosis. I have done some of those same dives now on trimix and remember every minute of the dive, the features of the wreck, and am more aware of my buddies and environment.
But all good things come with a cost and for helium it's just that...the expense. At our local fill station you can get nitrox for .10/ft and trimix is .35/ft. So you can see that trimix is significantly more expensive. But for anything past recreational depths it is absolutely necessary. If you can't afford the gas, the right gas,then you shouldn't do the dive.
Hope that helps
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