At what point is filling doubles two fills?

[Omicron]

Higher stress on the components?

[Bubblemaker]

Friction, the size of the Hp Stage is usually the size of your pinky, So it takes longer to get more volume at the higher pressure.

K

[WIdiver_Paul]

The only time you could justify a half-price double fill is if you had your isolator closed and really only got a half fill. But then you're dealing with mismatched uneven bouyancy issues. Double price is just the cost of having the kind of fun we get to have when diving doubles and all the great runtimes we get out of them. When diving with recr. divers with singles, I get double the bottom time that they do on all the dives when I've got 260cf versus their 80x2=160 cf and usually I don't have to waste the gas when doing tank swaps like they do. A few bucks in air is way worth the extra run time we get, IMHO.

If you do the math on my doubles, from 1500 psi to the rated pressure of my HP 3442 psi tanks I would be starting with 113cf and getting a topoff of 147 cubic feet. This is almost double a 3000 psi AL-80 anyhow! In reality i'm getting over 3 fills for the price of 2 when I start with empty tanks, so in the end we really end up getting our cake and eating it too!

Chris, I think you forgot that even if your fills were $25, you're only needing a total of 2 fills on a 2-dive/tank charter over a 2 day weekend, so it would only be $50, and not $100. We don't need to swap our tanks like the singles divers do, we just recalculate thirds and actually get to use all our gas. Ain't it grand?

Some shops do charge by the CF for even Nitrox (Cave Excursions in FLA does). This is fair in most respects. It's definitely fair to charge per CF for Helium and Argon, that stuff ain't cheap. If they started charging per CF for air, i'd lose much more than i'd gain!

And after that accident at Cave Excursions and the horrible death that happened with Fran, I don't think we're paying enough for our fills. Tami at Diversions in Madison only charges us $5 a fill! That can only barely cover her maintenance costs on the compressor, if that even. I know she just had to replace all of her fancy Hyperfilter towers so that she keeps us in the highest quality and safest air in town. Throw insurance, taxes and labor in there, it's definitely a "loss leader". But it gets people in the shop and hopefully sales. It really is true that to make a million on a dive shop, to invest 2 million!

At Hoofers we've talked about buying our own compressor, but with all the costs and time, it's not worth it. Those poor divemaster candidates that toil away in the shop doing fills for you earn every penny they make, as does the shop. This is off topic as well, but yes, Leisurepro may be cheaper, but there are real people at your LDS that need to eat just like you do - appreciate them and spend your money with them! Keep your money here in Wisconsin, I know the LDS's here appreciate every customer that walks in the door, i've never been treated as nicely by retail people as I do when going to a diveshop. They love diving just as much as we do, and it shows!

And if your LDS gives you the service, please please make your purchase with them. I heard the heartbreaking story from one LDS that did all the measurements for a large government group of divers for their drysuits only to lose a 5 digit sale to another LDS because the price was a few bucks cheaper! I know it's common practice to do the window shopping at the LDS and make the purchase online, but we need to stop that. They're here for us, we need to be there for them as well!

Happy diving all!