Short fills- how short is too short?

[toonchoon]

i work at a dive shop and fill my own and customers AL80's to about 3300 PSI, that end up at about 3000PSI once full and cool. They pay for the fill, and I fill it.

I don't really care if i get out and my tank is at 2800 or so. But anything less shortens my dive, because I usually surface with about 200-300 psi left in the tank.

 

[CJ Waid]

I just learned how to fill tanks at the dive shop (funny, my sudo-girlfriend was allowed to fill them before I was, I am at the end of the DM course and getting ready to start the IDC, she is still waiting to finish up her Open Water)...

I filled about 20 tanks last week, and one of the guys just bought two hp steels, we were standing around and my buddy visualed them, then I filled them from zero, tanks got real hot, the bank read 3,500, they cooled down to 3,200... So.... sometimes it is just not having a feel for how a tank will cool, as opposed to how much air was added (because that makes a big difference in how hot it is going to get, and eventually have to cool down)...

Besides, why would you want to keep stretching a 3,000 psi tank out, 2,800 won't push against the walls as hard as 3,000 will... if 200 psi makes a difference on a dive, you need to either switch to nitrox, doubles or work on your air consumption.

 

[ReefHound]

Besides, why would you want to keep stretching a 3,000 psi tank out, 2,800 won't push against the walls as hard as 3,000 will... if 200 psi makes a difference on a dive, you need to either switch to nitrox, doubles or work on your air consumption.

And 2600 won't stress a tank as much as 2800, and 2400 won't stress it as much as 2600, and 2200... That sounds like a line of BS you learned from your shop to explain away short fills. How you handle and store your tank will have a far more significant impact on your tank than filling it to 3000 psi.

200 psi makes a difference to every diver. In fact, it makes the most difference to the divers with low air consumption since they could get a lot more extra dive time out of that 200 psi than an air hog.

What the heck does nitrox have to do with air consumption and short fills???

 

[fishb0y]

Besides, why would you want to keep stretching a 3,000 psi tank out, 2,800 won't push against the walls as hard as 3,000 will... if 200 psi makes a difference on a dive, you need to either switch to nitrox, doubles or work on your air consumption.

WHAT?!? STRETCH THE TANK!?! It's official, we have a winner (wiener) :35:

 

[lamont]

Besides, why would you want to keep stretching a 3,000 psi tank out, 2,800 won't push against the walls as hard as 3,000 will... if 200 psi makes a difference on a dive, you need to either switch to nitrox, doubles or work on your air consumption.

the DOT regs rate tanks to take up to a 25% overfill at 120F provided they cool down to service pressure at 70F.

 

[JGBrown]

I was very happy for the last month or so, because all the rental tanks I was getting were overfilled to around 3400PSI, in 44F water
the shops gauges were typically reading around 3500.
I've never had a short fill, I just poke around the rental tanks till I find a nice tall one if I find one below 2800
But if I forget to check before leaving the shop I'm not going to come back all bent out of shape, and not just because I'll run out of air first seriously, at 10$ for the tank+air, or 7.50$ for a fill, its cheaper then a 6 pack of beer, and I'm not measuring the fills in a case of beer to make sure I get exactly 2130mL.

 

[diverdowndh]

if 200 psi makes a difference on a dive, you need to either switch to nitrox, doubles or work on your air consumption.

This made me laugh. This is like filling your gas tank and having the station "decide" that a gallon less won't hurt you, you need to change the way you drive (put don't think about paying less!). I'd switch dive shops not the way I dive....

 

[CJ Waid]

Wow a bunch of cocky internet divers... You are Cool.

Honestly, if 200 PSI makes that big of a difference to you, than I apologize, go ahead and whine about it, but if you are diving that close to the edge of your air supply, get doubles.

 

[ReefHound]

Wow a bunch of cocky internet divers... You are Cool.

Honestly, if 200 PSI makes that big of a difference to you, than I apologize, go ahead and whine about it, but if you are diving that close to the edge of your air supply, get doubles.

At least we're divers, not so sure about you. Still waiting to hear what nitrox has to do with air consumption.

 

[diverdowndh]

whining? dude, this is a forum... a place to voice your opinion, not to start tossing insults. I am a diver, pay big dollars for EVERY 100lbs in a tank. Yes, 200lbs makes a difference, to me if not you. you make me laugh again about using doubles... right, a recreational diver using doubles because a dive shop doesn't fill a tank? Cmon, that isn't the answer...