At what point is filling doubles two fills?

[FreediveWI]

I know of one shop owner who complained that it was the last part of the fill, when the tanks were at their highest pressure, that did most of the wear and tear on his compressor, and thus he didn't have a problem charging for any fills that he did.

The last time I actually bought an air card was from Pirate's Cove. They used to sell 50 fill cards for $100- which brought the price down to $2 a fill. I don't know what people are charging now.

Charging by the cubic foot makes sense, especially for trimix fills. If the shop has a Helium analyzer they could do that very easily.

Chris, since you have a core group of guys you dive with you could all look into going in on a compressor together. Mixing gas isn't as hard as some people make it out to be and both Gert and I are nitrox/trimix blending instructors who could certify you to run your own show.

I will say that, while it might make trimix diving cheaper, you might be suprised to find out how much just a standard air fill costs you.

Jon