MOD Stickers

[stuartv]

@stuartv it isn't an excuse to not analyze the tank. It's a historically deadly variable that can be minimized with a $150 max purchase for aluminum bottles.

Unless you are somehow able to be SURE that the person filling that cylinder will never put a gas in it that is different than what the MOD sticker says, I just don't see it.

And I do realize that some of you fill your own cylinders and so you may be able to do that.

But, I don't fill my own cylinders. I believe fill station operators occasionally make mistakes. Anything from doing a blend that ends up "off" from the target (e.g. 70% when I asked for 80%) to just putting the completely wrong gas in. So, I don't see how dedicated bottles really would make a difference - to me. I analyze when I get a fill, and label the tank with the mix, my initials and the date, regardless of what the MOD sticker says. If the MOD sticker does not match what's in the tank, I take the MOD sticker off.* No big deal to take it off, since it cost me almost nothing. No thought of "that sticker cost me money and I'll just have to put another one right back on after this one dive. I'll just leave it on there and remember that it's not really correct for this one dive. No big deal. The actual MOD is deeper anyway, so I'm safe."

I would rather use a process that makes it normal to change the MOD sticker every time, so that I know it always matches what is in the cylinder than a process that requires me to do something "exceptional" in the case that my cylinder ends up with a fill that does not exactly match the label. A process where, if I don't have to change the MOD sticker, "oh, that's nice." Not, "oh, dang. The guy put 50% in my O2 bottle and O2 in my 50% bottle. Crap. I don't have time to drain these bottles and redo them. Crap. I need to find some stickers..."

And I analyze again before I use it.

Anyway, I think we're going pretty far OT and I'm not trying to tell anyone else how to manage your cylinders or MOD stickers. In the end, it seems that we are all going to analyze before we dive and make sure the MOD sticker matches the gas... I was just chiming in on what I do for MOD stickers. Not trying to start a debate on whether to dedicate cylinders to specific gases (thanks PfcAj! ).


* now that I think about it, if I am asking for a fill that does not match what the MOD sticker says, I will start removing the MOD sticker before I hand the cylinder over for a fill. That will help ensure no cylinder ever has an MOD sticker that does not match the contents. But, going further down that road, it seems like maybe that should be SOP for ALL cylinder fills. No MOD sticker is ever on a cylinder until after it has been filled and analyzed. Only then would the MOD sticker be put on. That would make SURE that you never have gas that doesn't match the MOD sticker. Unless you put the sticker on the wrong cylinder right after you just analyzed it....

 

[tbone1004]

@stuartv mod stickers are a big, obvious, easy check. If you have a permanent bottle for EAN80, and someone shorts you to EAN70, you don't have to change the MOD sticker. Sure the MOD is now 40 instead of 30, but who cares? You aren't using EAN80 on anything where you will have a mandatory 40ft stop anyway.

beauty of standard gases. You really don't gain a whole lot deco advantage with custom mixes. Hell, a 60min dive at 100ft on EAN32 has 26 min of deco on EAN50 vs 16min on O2. 10mins is not significant enough for me to mess with EAN80 to save less than 10 mins *decoplanner doesn't let me use 30ft as a last stop*

 

[boulderjohn]

Some people seem to think there are only two choices--standard gases or best mixes. In their worlds, that may be true, but that is not the world in which I do most of my dives.

I am not going to a shop, dropping my tanks off, asking for a specific fill, and coming back later to pick them up. I don't have that luxury--it isn't even an option. I do all my own mixing, and I do all the mixing for the others with whom I dive. That is our only choice. Some of that is done in my home. Most of it is done on the prairie in New Mexico, using the supply bottles lying down next to my booster in my van. When I make the initial fills at home, I have pretty good control over what I can do. Once on the prairie, we are working with a philosophy that is more like "What can we make with what we have, and what can we dive with what me make?"

 

[stuartv]

Actually, Best Mixes are a superset of Standard Gases. There is no gas choice that isn't allowed by Best Mix (as practiced by me, anyway). It is only Standard Gases that are limiting.

Best Mix doesn't mean I HAVE to use the gas that will give me exactly 1.4 on my ppO2 at max depth. It just means I can. But, I can also factor in things like "what can I make with what I have?" And I can factor in "my target dive site has a max depth of 140, but I might have to divert to a different site and that has a max of 160."

@tbone1004 I know you wouldn't change a dive plan (i.e. gas plan) to shave off 10 minutes of deco. But, I would! At my level of technical diving, 10 minutes is a non-trivial amount. And, really, why wouldn't I? To save re-labeling my cylinders? Really? I will happily peel the tape, put on new, and write on a new MOD, if it saves me 10 minutes of hang time.

 

[stuartv]

@stuartv mod stickers are a big, obvious, easy check. If you have a permanent bottle for EAN80, and someone shorts you to EAN70, you don't have to change the MOD sticker. Sure the MOD is now 40 instead of 30, but who cares?

I do. I'm too new at this to be cutting corners and diving with a label that is 10% off on the mix seems like cutting corners, to me. I would do that to save 3 minutes of time putting on some tape and writing the correct info?

I want my computer setting, my MOD sticker, my plan, and the actual gas in the cylinder to all match.

I do not want to dive a cylinder full of EAN70 with a sticker that says 80.

I do not want to tell my computer I am using 80 when I'm really using 70.

I do not want to tell my computer I am using 70 when my bottle says 80.

Etc..

If I planned for 80 and I got a fill that is 70, and I don't have the option to fix it, then I'm changing my plan, my computer, and the labels on the cylinder to match what is actually in the cylinder.

Hopefully, my buddy didn't get 80 and I got 70. Then one of us is going to have to get their fill fixed.

 

[PfcAJ]

Who leaves the fill station with a gas 10% off from the target?

Do you guys really do this?

I can’t even.

 

[tbone1004]

Who leaves the fill station with a gas 10% off from the target?

Do you guys really do this?

I can’t even.

I certainly don't. I give them about 2-3% before I get grumpy.

@stuartv don't confuse MOD stickers with mix stickers, VERY different things

 

[Lorenzoid]

@stuartv don't confuse MOD stickers with mix stickers, VERY different things

Good point. They almost never give you a mix richer than you asked for; if there's an error, it's that the mix is too lean. Still within the permanently marked MOD.

 

[tomfcrist]

Yeah...I took a 50% bottle with 70 clearly marked on it into a shop while traveling a few years ago. Asked if they did deco fills (which they say they did) and asked for 50%.

I’ll be damned if the monkey at the fill station didn’t put 1500psi of O2 in it and top it off with air.

 

[stuartv]

He used Inert Air, right?

LOL