Nitrox best mix question

[black1]

Hello all, this Saturday im doing a wreck dive off of Pompano Beach Florida called the Guy Harvey, it rests in 140ft of water and this is part of my AOW Deep dive, ive done 106ft the weekend before perfectly and i used a nitrox 36% for that which is my usual mix. Im not sure we (my instructor/friend) will hit bottom but probably close to it say aroun 135ft and she suggested to fill my tank with EAN30 for this dive, at PPO2 1.6= 143ft, I would like to stay in the PPO2=1.5 range for comfort (maybe current,challenges, etc) and this gives me 132ft as a MOD. My question is should i stay at this mix as she suggests or should i use EAN28 which gives me a PPO2= 1.5 at 143ft. and gives me a little safety room in case there is a strong current or some type of strenous activity that may come about?

 

[Diver0001]

Are you going to be diving to 140ft or is that just the depth on the bottom?

Ideally you take the right mix for the job. If you can get a custom mix then work it out and get exactly what you need. Pushing the ppr02 isn't a good idea if you ask me. The limits were set like that for good reason.

R..

 

[wedivebc]

Hello all, this Saturday im doing a wreck dive off of Pompano Beach Florida called the Guy Harvey, it rests in 140ft of water and this is part of my AOW Deep dive, ive done 106ft the weekend before perfectly and i used a nitrox 36% for that which is my usual mix. Im not sure we (my instructor/friend) will hit bottom but probably close to it say aroun 135ft and she suggested to fill my tank with EAN30 for this dive, at PPO2 1.6= 143ft, I would like to stay in the PPO2=1.5 range for comfort (maybe current,challenges, etc) and this gives me 132ft as a MOD. My question is should i stay at this mix as she suggests or should i use EAN28 which gives me a PPO2= 1.5 at 143ft. and gives me a little safety room in case there is a strong current or some type of strenous activity that may come about?

I think you would be wise to back off the PO2 a little in consideration of strenuous activity.
May I ask what agency you are training with? I am surprised that any one would allow you to go that deep on an AOW and would encourage a high PO2 for said dive. Most agencies I am aware of mandate a maximum 1.4 PO2, at least for training dives.

 

[Reg Braithwaite]

Hello all, this Saturday im doing a wreck dive off of Pompano Beach Florida called the Guy Harvey, it rests in 140ft of water and this is part of my AOW Deep dive, ive done 106ft the weekend before perfectly and i used a nitrox 36% for that which is my usual mix. Im not sure we (my instructor/friend) will hit bottom but probably close to it say aroun 135ft and she suggested to fill my tank with EAN30 for this dive, at PPO2 1.6= 143ft, I would like to stay in the PPO2=1.5 range for comfort (maybe current,challenges, etc) and this gives me 132ft as a MOD. My question is should i stay at this mix as she suggests or should i use EAN28 which gives me a PPO2= 1.5 at 143ft. and gives me a little safety room in case there is a strong current or some type of strenous activity that may come about?

Get a new instructor. Stat. I'm not saying there's anything wrong with her choice, but I am saying you are second-guessing the person who is teaching you how to stay alive under incredibly demanding circumstances, diving a wreck near the limit of recreational diving, and who will be responsible for rescuing you if something goes wrong on your dive.

You need to find someone who you will trust with your life. Not that she isn't trustworthy, but clearly you haven't forged that bond with her. She's a friend, great. A dive buddy, excellent. But your relationship with an instructor is something else entirely. An instructor is not your buddy, an instructor is someone who is dedicated to keeping you alive and progressing at the most appropriate pace without any consideration for your feelings or how much you pay to be taught.

Now that I say that, I almost think the expression "instructor/friend" is a contradiction in terms

p.s. You lead an exciting life! When I did my AOW deep dive, it was just 87 feet. You've already done 106' and are gearing up to go to the adge of the abyss at 130'! My instructor cautioned me not to go rushing off and try to dive over 100' for quite some time. He's an ex-military diver with a huge amount of wreck and commercial diving experience, I trusted him and his advice implicitly.

 

[The Kraken]

What Diver0001 said . . .

the K

 

[D_B]

I learned a max PO2 of 1.4, and to be backing off from that if cold, or stressed.
... most that I've read suggested a higher PO2 ONLY when doing deco, and only because your just relaxed and not doing anything

 

[jerry_h]

What agency are you training with?

 

[ScubaSteve]

I would heed the warnings given here and seriously think about getting a new Instructor or even switching agencies. From my training experience, what you are doing is not recommended for the reasons listed above. Do some research and make your decision but altering your P02 to increase your MOD is the wrong decision IMO. It is a recipe for an eventual disaster.

 

[Walter]

I'd dive the Guy Harvey with EAN 26 which would allow me to make a rescue at the bottom without exceeding 1.4. I've found the bottom there to be at 143.

 

[jtivat]

I would not push your PPO2 above 1.3 there is just no good reason to risk it. I would be looking for a new instructor but thatÃÔ just me.