Cheaping out on Trimix - travel gas

[Marie13]

you are correct but helitrox require you to already be advanced nitrox certified or be taking advance nitrox at the same time. there is no way to be helitrox certified and not also be advanced nitrox certified.

I know this. I’m in the midst of the class.

 

[loosenit2]

You need to do TDI Advanced Nitrox in conjunction with Helitrox to get up to 100% O2 (above 40%).

Explain how you come to this please. TDI says AN qualifies the "Ability to dive using EAN 21 through 100 percent oxygen". Not sure why you would do that without DP and the ability to plan decompression but...

 

[rjack321]

You cannot do heliox without AN either beforehand or at the same time.

NONE OF THIS IS RELEVANT TO THE OP HOWEVER

He/she/they are new to trimix but are now balking at the fill costs and want to use a trimix backgas, a deco bottle, AND a 3rd gas to save breathing that 35% helium. They are not full trimix and have no experience or training with multiple stages. Those of you in the midst of intro trimix courses or only having gone this far in your training and experience might want to listen instead of talk.

Bringing along a "travel" gas or a second deco gas is not a casual no big deal thing. People die breathing the wrong gas and its shockingly easy to do when you carry extra bottles, have no supervised training in their use, and start doing multiple gas switches when you are only familiar with one.

 

[Alekseolsen]

Are you solo diving too? I couldn't tell. What is your buddy diving?

Starting the dive on the wrong gas (50% in this case) is shockingly easy to do and to have you swimming along at 30m working at a ppO2 of 2.0 is very likely to be life threatening. Innocent seemingly obvious mistakes like this is how people die.

As a new trimix diver I would suck it up and accept the minimal extra cost of diving exactly how you were trained - backgas and one deco gas. If you can't afford that extra 20 or 40 euros etc, then don't do the dive. Making these kinds of logistical compromises at the beginning of your trimix career is especially unwise since you don't have the mental habits or muscle memory established yet for anything.

Thanks a lot for the feedback, definitely not an error I'd expect to be "easy to do"

I'm not diving solo, the buddy I usually do these dives with took the course together with me, and we're diving similar rigs, and been considering considering that bottom stage together.

 

[Alekseolsen]

You cannot do heliox without AN either beforehand or at the same time.

NONE OF THIS IS RELEVANT TO THE OP HOWEVER

He/she/they are new to trimix but are now balking at the fill costs and want to use a trimix backgas, a deco bottle, AND a 3rd gas to save breathing that 35% helium. They are not full trimix and have no experience or training with multiple stages. Those of you in the midst of intro trimix courses or only having gone this far in your training and experience might want to listen instead of talk.

Bringing along a "travel" gas or a second deco gas is not a casual no big deal thing. People die breathing the wrong gas and its shockingly easy to do when you carry extra bottles, have no supervised training in their use, and start doing multiple gas switches when you are only familiar with one.

And thanks a lot to you to - the ease of mixing up comes as a surprise to me, but very happy I asked.

 

[Marie13]

Explain how you come to this please. TDI says AN qualifies the "Ability to dive using EAN 21 through 100 percent oxygen". Not sure why you would do that without DP and the ability to plan decompression but...

The DP stuff is covered under Helitrox. I did the above 40% comment as divers have basic nitrox class that covers them up to 40% before doing AN.

 

[Marie13]

So, as it happens to be, I'm currently a newbie Trimix-diver.
Due to the cost and hassle involved in getting a trimix fill, I usually get a 21/35, which is topped up with air after the first dive, to get more dives out of the fill.

My local divesites includes a bit of swimming in the 10-30 meters range both before/after the deep part of the dive, thus I've been playing with the thought of bringing a stage with ie. EAN32 to use as "travel gas". Normally I'd have 1 stage with 50% for limited deco, so now considering bringing two stages.

I dont intend on including the stage with EAN in gas planning, just utilise it to save on the helium.

Any thoughts appreciated!

Just curious - what are you paying for Trimix?

 

[Alekseolsen]

Just curious - what are you paying for Trimix?

Roughly 140 Euros for D12's with 21/35, but that can only be arranged through my LDS Thursday evenings(they bring the bottles to a different shop for fills), if I want a fill other days, then I have a 90 minute drive each way - so the hassle is as much part of it as the cost. I won't be taking that extra stage anytime soon though!

 

[MichaelMc]

As with others, I don't know what agency certifies trimix divers but does not allow 100% oxygen for deco.

IANTD rec trimix has deep and nitrox as prereqs and lets you add He to your one gas (e.g. 32/15 28/25 21/35) but adds to neither O2, depth nor number of gasses. RAID has a similar option with their deep class.

I recently took IANTD rec trimix, and it is very much just one gas. As benign as say 28 might be.

 

[boulderjohn]

IANTD rec trimix has deep and nitrox as prereqs and lets you add He to your one gas (ie 32/15 28/25 21/35) but does not add to O2, depth nor gasses. RAID has a similar option with their deep.

I recently got the IANTD, and it is very much just one gas.

Well, then, that would explain it. He is IANTD according to his profile page.