LDS and Nitrox fills.

[imjustdave]

So I walked into a new dive shop to me a few days ago as I need a fill and needed to shop for a few things.

I asked how much a fill would be and they had a chart on the wall showing all the difference pricing. First it was broken down to size of tank, LP or HP then Air, 32% and then Custom Nitrox. I asked for 32% and they said sure NP. While I waited I did a little shopping and talked about Crab lic info and I could hear them slowly filling the tank which I liked and then they say you know its a little warm if you want it now NP but if you want to come back in a few hrs we can top it off cold so you have a full 3500 fill cold. It made sense so I left and everything so far seemed great, close to work, nice guys, ok selection of stuff that I might want to buy.

So I return and set the base line of 21% hook up the analyzer to test my tank..... and it stops at 29%.... being a new shop to me unhook everything let the tester return to air and test again still 29% So I asked I'm reading 29% but wanted 32%, then they replied back with what was in the tank when you came in? I said around 22% as the last few fills were air. and they said yup sounds about right. They mentioned that they partial filled in their bank tanks, and bank 32%.

Should I expect 32% with a partially filled tank when I ask for 32%?
should I expect them to test the tank prior to filling?
My tank is 02 clean, and stamped accordingly.
If I come in with a tank that has a different amount then request should I expect to pay 2$ more for a custom fill to get it where I want it? even if 32% is a cheaper option.

In this case I started with about 22% and 1200 PSI from my memory I could have drained the tank and gotten closer to 32% then paying even more for a custom fill. but that just seems strange to empty the tank out to then fill back up.

Based on my tank and psi
I paid $14 for 32%
I think air was $10

In comparison I have 2 other dives shops that will fill nitrox to what ever level I want with what ever level is in the tank to start with. If I ask for X% that is what I get and the pricing is Air or Nitrox and not varying pricing based on % of Nitrox.

Am I expecting to much for my $14?

 

[Jim Lapenta]

If you wanted 32% and paid for it you should have told them to empty the tank and fill it from the banked 32%. Or added enough O2 then topped off with air or the bank to get what you asked for. When I get nitrox fills I get what I ask for. It's not hard if the shop partial pressure blends. There are charts and the full version of v Planner will tell me exactly what needs to go in a partially filled tank. If they only bank then your tank does not even need to be 02 clean. They or you just need to empty it and fill it with the right gas.

 

[rongoodman]

A local shop did the same thing to me and I've never darkened their doors since. I picked up a set of doubles I had asked to be filled with 32% and found them to analyze at 27%(and the fill was 15% short to boot). A little arithmetic showed that they had just dumped 32% on top of air already in the tanks. To add insult to injury, they stripped off my custom DiveSigns name tags to make room for PADI Nitrox bumper stickers, for which they wanted to charge me.

 

[kelemvor]

I'm surprised a shop would be okay selling a fill where they missed the mark by 3%. The value in their bank isn't what's important, the value in your tank is.

Every shop I've been into who fills of premixed banks will dump the contents of my bottles first. The only exception has been when I went to a shop with say 1000psi of 40% and asked them to top it off with the 30% they had banked at a shop in key largo.

Anyway, if I ordered 32 I'd expect 32 and be surprised if the shop botched the fill. Unless I was depending on that extra 3% to make my profiles, I don't think I would raise too much of a stink. I would just remember not to go back to that shop if I had another option.

 

[Brandon]

So it sounds like the OP went into a shop that banked 32%, he asked for 32%, and the fill station operator put 32% on top of a partial air fill. The final analysis came up well short of that, but that's not really the fill station operator's fault... unless you told him otherwise, it wasn't a stretch for him to assume you had 32% in there already, or that you didn't care that you'd come up a little short on the 02 analysis.

Lots of us end up doing this when swapping back and forth between air and nitrox. Congratulations, you've now joined "Slightrox" diver family. Please see your local PADI rep to pay the requisite certification fees, and we'll get a card in the mail to you! =)

If you wanted to convert a partial air fill to a 32% fill you should have either 1) drained the cylinders as low as possible (below 100PSI), or 2) let the fill station operator know they contained air so he would know that a partial pressure, or custom continuous blend, would be required to get you up to 32%.

Also, it's more than a good idea to have contents labels on all cylinders used for anything other than straight air. That may have prompted the fill station operator to clarify your request.

 

[dive_more]

I am with brando, it was not their fault, and it is also not traumatic, empty your tank before the next fill

 

[Wookie]

^^I'm with these guys. Sure, they could have analyzed your cylinder and calculated how much O2 to dump in to make 32, or assumed you had 32 in your properly labelled nitrox cylinder and assumed you wanted a top off. Set your dive computer for 29% and go have a dive riot. Next time don't assume they know what is in your tank, or drain the air you had in it and get the real deal.

It's 4 bucks. Your cup of morning starbucks costs more than that. You both made an assumption. You were both wrong.

 

[DogDiver]

We pay by the cubic foot. If you come in with say a HP steel 95 with 1800 psi and fill to 3600 psi. You only pay for the 45 cubic feet of 32% you put in the tank. Banked nitrox is 11 cents a cubic foot so this fill would cost $4.95.


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---------- Post added July 12th, 2014 at 01:34 PM ----------

In North Florida cave country, banked nitrox is Cheeper than air.

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[Brandon]

Okay, we have to stop posting pictures of the fill station at Amigos in response to any nitrox fill thread... it's not a fair comparison for the rest of us, and I'm jealous. =)

Though I am returning to cave country in December...

 

[Wookie]

It's also off topic. Guy wants to know if he should be pissed, and he's not likely to drive to N. Florida to get fills.