MOD marking question

[do it easy]

Is there a consensus on how to mark back gas when the MOD is deeper than the planned dive. For example, I'm diving to 100ft on air, so should I mark my backgas as 100ft (planned depth) or 185ft (MOD)?

Call Guiness- First post ever!

 

[Soggy]

You mark the MOD based on the actual MOD of the gas.

For air, that would be about 20 ft

 

[Inst. Dean]

I agree. In case something goes wrong and you get deeper then your planned depth, you want to know the MOD of the gas you are diving. You don't want to have to figure it out when you are down there.

 

[Boogie711]

You don't mark back gas. You mark your stage bottles.

And you DON'T dive AIR (icky!) to 100 feet.

 

[Soggy]

You don't mark back gas. You mark your stage bottles.

Well, you don't stencil it, but you mark it on the analysis sticker.

 

[do it easy]

You don't mark back gas. You mark your stage bottles.

And you DON'T dive AIR (icky!) to 100 feet.

If you were diving best mix at 100ft, you wouldn't mark your back gas to indicate that it might no be a good idea to breathe below 100ft?

 

[Soggy]

If you were diving best mix at 100ft, you wouldn't mark your back gas to indicate that it might no be a good idea to breathe below 100ft?

Yeah, you would mark the MOD on the analysis sticker, but in DIR we don't dive best mix, we dive standardized gasses.

Here they are:
http://www.divetekadventures.com/Technical_standardGas.htm

 

[Boogie711]

Valid point on the gas analysis sticker, Soggy - thanks.

And Do it Easy - Soggy is, as ever, correct. DIR divers don't dive "best mix." That makes life unnecessarily complicated. For recreational diving <100 feet, it's either 32% Nitrox or Trimix 30/30.

 

[Snowbear]

If you were diving best mix at 100ft, you wouldn't mark your back gas to indicate that it might no be a good idea to breathe below 100ft?

Since you are asking this in the DIR forum, you are looking for the DIR answer, correct?

What these folks are getting at is:
- It's not DIR to dive air to 100'... Air is for tires and really, really shallow dives

- DIR "Best mix" for a 100' dive is your choice of EAN32 or Triox 30/30. The MOD and tables are essentially the same for both (If ya need to get nitpicky about the difference, your dive is too aggressive and you should plan accordingly).

- The only tank markings on back gas are on the analysis sticker. You mark the actual MOD of the gas in the tank.

 

[do it easy]

Yeah, you would mark the MOD on the analysis sticker, but in DIR we don't dive best mix, we dive standardized gasses.

Here they are:
http://www.divetekadventures.com/Technical_standardGas.htm

When you write analysis sticker, I'm assuming you mean the little 1 inch tape, not 3 inch letters. Is the analysis sticker just for identifying the contents on the boat/shore, i.e., it itsn't used underwater?