Another Nitrox class question

[fjpatrum]

I tried to do a search but most of what comes up is about PADI's Nitrox class.

I'm considering doing a nitrox class and the shop I use does SDI. I don't know much about the course other than what's on the TDISDI website : https://www.tdisdi.com/userportal/online_training/index.php?course=SDI

My primary reason for doing this cert is the supposed (can't tell if it's fact or not) lower amount of fatigue after multiple dives on nitrox versus air. These will be shallow dives so I'm not really concerned at all about bottom time as NDLs for the depth I'm planning (30-60') are long enough to be reasonable dives.

Here are my questions:

1) Is Nitrox even feasible for use at these depths? (I haven't taken the course yet so I'm not sure what recommended depths and mixes are...)

2) For those that notice "reduced fatigue" what does that mean to you and how many dives? IE I'm scheduled for 2 dives per day right now, and hoping to do up to 5 dives per day for 3 or 4 days with a couple more days of rest and/or 1 or 2 dives. As stated above, this is the main reason I'm considering this course.

3) I'm planning to use my own tanks but I only have 3. If I make one a "nitrox tank" will I gain any benefit by diving 1 tank out of every two (or three) as nitrox? Will I have anything else to worry about other than making sure my computer is in the right mode for each dive?

4) Is it unsafe (remember I haven't taken the course yet) to go back and forth with fills in a tank? I believe I've read somewhere that a nitrox tank should stay a nitrox tank unless you get it inspected again (is that the same as "O2 clean???) but I'm not sure about that. I don't usually dive deep enough or consistently enough to warrant the use of Nitrox, typically, so converting a tank to dedicated Nitrox is something I haven't committed to just yet. Is it worth it?

5) The SDI online course is $119 versus the $195 for the PADI online course. Most of the local shops and the couple I've called in FL (where I'll be doing the diving) are all around $160 for an actual instructor-led course. A few dollars here or there isn't my concern, but I'd like to know if there's a significant difference (if anyone knows) in the course materials provided by SDI and PADI. (IE does SDI not provide tables because they mandate computers or something like that?)

 

[Mayor]

Take the class from any organization but sitting down with an instructor will teach you some little tricks. The online stuff is ok but you miss out on the experence insite to enriched gas. Some even review gas management etc. If you would like I can make some instructor recomdations but it's really worth your time and money to have it.

I tried to do a search but most of what comes up is about PADI's Nitrox class. I'm considering doing a nitrox class and the shop I use does SDI. I don't know much about the course other than what's on the TDISDI website : https://www.tdisdi.com/userportal/online_training/index.php?course=SDIMy primary reason for doing this cert is the supposed (can't tell if it's fact or not) lower amount of fatigue after multiple dives on nitrox versus air. These will be shallow dives so I'm not really concerned at all about bottom time as NDLs for the depth I'm planning (30-60') are long enough to be reasonable dives. Here are my questions:1) Is Nitrox even feasible for use at these depths? (I haven't taken the course yet so I'm not sure what recommended depths and mixes are...)2) For those that notice "reduced fatigue" what does that mean to you and how many dives? IE I'm scheduled for 2 dives per day right now, and hoping to do up to 5 dives per day for 3 or 4 days with a couple more days of rest and/or 1 or 2 dives. As stated above, this is the main reason I'm considering this course.3) I'm planning to use my own tanks but I only have 3. If I make one a "nitrox tank" will I gain any benefit by diving 1 tank out of every two (or three) as nitrox? Will I have anything else to worry about other than making sure my computer is in the right mode for each dive? 4) Is it unsafe (remember I haven't taken the course yet) to go back and forth with fills in a tank? I believe I've read somewhere that a nitrox tank should stay a nitrox tank unless you get it inspected again (is that the same as "O2 clean???) but I'm not sure about that. I don't usually dive deep enough or consistently enough to warrant the use of Nitrox, typically, so converting a tank to dedicated Nitrox is something I haven't committed to just yet. Is it worth it?5) The SDI online course is $119 versus the $195 for the PADI online course. Most of the local shops and the couple I've called in FL (where I'll be doing the diving) are all around $160 for an actual instructor-led course. A few dollars here or there isn't my concern, but I'd like to know if there's a significant difference (if anyone knows) in the course materials provided by SDI and PADI. (IE does SDI not provide tables because they mandate computers or something like that?)

 

[Doppler]

The SDI course is computer-based... if you want a more thorough course with the focus on giving you a more detailed comprehension of diving nitrox, take the TDI course.

 

[redacted]

1. You will not see much advantage from nitrox on 30 ft dives but you should see a good payoff at 60 feet.
2. I am one who believes I feel better on nitrox but this is with 4 to 5 dives pere day all in the 70 to 100 ft range.
3. If your supplier insists on O2 cleaned tanks, you may have a problem. If your shop banks EAN then you should be able to use all of your tanks depending on the shop's policies. Check before you take the class.
4. I do not dedicate any tanks to nitrox. But that means I have to shop around for suppliers who do not require O2 cleaning (or even silly labels).
5. The SDI course will not cover tables. Check again total prices as there will probably be some charge for an instructor above the price for the online course.

 

[dbulmer]

To the OP,

Take the course regardless. It's always good to know that if you wanted Nitrox that you could - a decent instructor will show why.

 

[darushin]

The SDI course is computer-based... if you want a more thorough course with the focus on giving you a more detailed comprehension of diving nitrox, take the TDI course.

Agreed. I took sdi nitrox, but my instructor used the tdi book. The knowledge in the tdi book is a lot mor thorough then what i have seen taught in padi classes and sdi.

Daru

 

[Jim Lapenta]

I just got my SDI/TDI Instructor materials today. I can offer both the SDI which is computer based and the TDI Nitrox which is more in depth. I also offer the SEI Nitrox course that is nearly identical in content to the TDI course. The SEI course though requires dives. The TDI course is also available on line. I did it as part of my crossover and am impressed with the amount of material on it. Took me a few hours to do. The cost is only $10.00 more for the TDI on line over the SDI. You still need to make arrangements with a shop or instructor to go in and do the practical stuff. Analyze tanks, see the actual blending methods, etc. There is also the advantage of doing the course with an instructor as you do get the insights and experience lessons that no computer course can give you. As to your questions about it's use.

I do feel better after using it but it is highly dependent on number of dives, depths, surface intervals, and what I'm doing, As a DM it was not unusual for me to do 6 -8 dives a day on checkout weekends. There was a huge difference in using it on these days. As an instructor the most I do now is 5 and more often than not, no more than 4. Over a day from say 10am to 5pm and lasting up to an hour. But these are shallow OW dives below 35 feet for the most part. I see little no benefit in it for those as we are doing good SI's and not working hard.

IMO it really does not come into it's own until you start doing dives in the 50-100 foot range. To directly answer your questions:

1) Is Nitrox even feasible for use at these depths? (I haven't taken the course yet so I'm not sure what recommended depths and mixes are...)

Yes

2) For those that notice "reduced fatigue" what does that mean to you and how many dives? IE I'm scheduled for 2 dives per day right now, and hoping to do up to 5 dives per day for 3 or 4 days with a couple more days of rest and/or 1 or 2 dives. As stated above, this is the main reason I'm considering this course.

See above

3) I'm planning to use my own tanks but I only have 3. If I make one a "nitrox tank" will I gain any benefit by diving 1 tank out of every two (or three) as nitrox? Will I have anything else to worry about other than making sure my computer is in the right mode for each dive?

Yes you will need to keep track of your PPO2 and CNS levels to a much greater degree. You will also need to watch your Nitrogen loading and decide when you are going to nitrox. Do you want less Nitrogen after the first dive or two or do you want it to help you off gas at the end of the day. Switching tanks on the same day is going to necessitate good planning and sticking ot those plans. Also will your computer do the switches and keep track of the information it needs to? If I were you I'd stick to nitrox on the 4 dive days and air on anything less if you are not going below 60 feet. Will make things much easier planning wise and tracking wise as well.

4) Is it unsafe (remember I haven't taken the course yet) to go back and forth with fills in a tank? I believe I've read somewhere that a nitrox tank should stay a nitrox tank unless you get it inspected again (is that the same as "O2 clean???) but I'm not sure about that. I don't usually dive deep enough or consistently enough to warrant the use of Nitrox, typically, so converting a tank to dedicated Nitrox is something I haven't committed to just yet. Is it worth it?

It depends on the blending method. If they are using the partial pressure method yes it can be unsafe to go back and forth unless you know for certain that you are putting O2 compatible air in the tank every time. As it blow up unsafe. If the shop you are using continuous blends, banks nitrox, or has a membrane system there is no problem with switching for mixes under 40%. They may say you need an O2 clean tank but in reality you do not. The simplest way and what I do is have all my tanks O2 clean and only get fills from those places with compatible air supplies. If that's not an option I'll rent a tank. But that is usually only on trips as I have two sets of doubles, 5 al 80's, 2 LP 95's, and an HP 80 as well as two older 72's all O2 clean. I only use local shops that happen to PP blend so I know all their air is O2 compatible.

5) The SDI online course is $119 versus the $195 for the PADI online course. Most of the local shops and the couple I've called in FL (where I'll be doing the diving) are all around $160 for an actual instructor-led course. A few dollars here or there isn't my concern, but I'd like to know if there's a significant difference (if anyone knows) in the course materials provided by SDI and PADI. (IE does SDI not provide tables because they mandate computers or something like that?).

The PADI on line course is computer as well I believe. And that is expensive for an online course. Don't forget you still have to pay a shop or instructor for the practical portion. You don't get a card until you've done that. Personally with what I've seen from your posts I'd go for the TDI class if on line is what you want to do. You'll get more info and a more thorough understanding on nitrox use.

 

[KY_BOB]

Good answer Jim.

(BTW, the new drysuit has still never been wet but I'm thrilled with the looks of it)

 

[Thalassamania]

I tried to do a search but most of what comes up is about PADI's Nitrox class.

I'm considering doing a nitrox class and the shop I use does SDI. I don't know much about the course other than what's on the TDISDI website : https://www.tdisdi.com/userportal/online_training/index.php?course=SDI

My primary reason for doing this cert is the supposed (can't tell if it's fact or not) lower amount of fatigue after multiple dives on nitrox versus air. These will be shallow dives so I'm not really concerned at all about bottom time as NDLs for the depth I'm planning (30-60') are long enough to be reasonable dives.

Here are my questions:

1) Is Nitrox even feasible for use at these depths? (I haven't taken the course yet so I'm not sure what recommended depths and mixes are...)

2) For those that notice "reduced fatigue" what does that mean to you and how many dives? IE I'm scheduled for 2 dives per day right now, and hoping to do up to 5 dives per day for 3 or 4 days with a couple more days of rest and/or 1 or 2 dives. As stated above, this is the main reason I'm considering this course.

3) I'm planning to use my own tanks but I only have 3. If I make one a "nitrox tank" will I gain any benefit by diving 1 tank out of every two (or three) as nitrox? Will I have anything else to worry about other than making sure my computer is in the right mode for each dive?

4) Is it unsafe (remember I haven't taken the course yet) to go back and forth with fills in a tank? I believe I've read somewhere that a nitrox tank should stay a nitrox tank unless you get it inspected again (is that the same as "O2 clean???) but I'm not sure about that. I don't usually dive deep enough or consistently enough to warrant the use of Nitrox, typically, so converting a tank to dedicated Nitrox is something I haven't committed to just yet. Is it worth it?

5) The SDI online course is $119 versus the $195 for the PADI online course. Most of the local shops and the couple I've called in FL (where I'll be doing the diving) are all around $160 for an actual instructor-led course. A few dollars here or there isn't my concern, but I'd like to know if there's a significant difference (if anyone knows) in the course materials provided by SDI and PADI. (IE does SDI not provide tables because they mandate computers or something like that?)

1) Yes Nitrox is feasible for shallower depths, but the biggest bang for your buck comes when it is used somewhat deeper.

2) I feel that there is significant fatigue reduction during multi-dive multi-day scenarios. There is no good empirical science to demonstrate this, but the study that is most often quoted to "prove" that it is not so did not test multi-dive multi-day profiles.

3) If you're gonna dive nitrox, set up all three tank for nitrox, it's not that expensive (at least it shouldn't be).

4) If you're using banked nitorx it does not matter, if your having partial pressure mixing done, it can be a problem. In fact, if you're using banked nitrox no special cleaning should be required, but it often is anyway.

5) I have no opinion.

 

[rongoodman]

If you have access to the TDI class, that's the one to take.