Short fills- how short is too short?

[NorthWoodsDiver]

WHen I paid for my fills it was costing me $8 each so when I had a tank with 2900 psi I complained and now all my tanks come back with at least 3100 psi (thats for al80's). I think the best fill I had on an al 80 from that place was 3146 psi. Now I dont pay for air anymore so I am happy to get 2800 or more but there should never be a reason to get less than 2800 especially when I dive cold water. My hp steel tanks get 3300 psi or so cause thats the limit of the compressors around my area. When you pay for air you had better get you moneys worth!!

 

[jefffalcone]

It's my understanding that dive shops don't make anything on air fills and some actually loose money on them. It is a service they provide to get people into the shop. With that in mind, should we really complain about a few hundred psi? It's been my experience that no matter what fill I have I can dive as long as I had planned to, and I'm a new diver, so my air consumption is not anything special. With a 2700 fill, I think most people will still be able to come as close to the ndl as the should and be back on the boat with more than 500 in the tank.

 

[redacted]

It's my understanding that dive shops don't make anything on air fills and some actually loose money on them. It is a service they provide to get people into the shop. With that in mind, should we really complain about a few hundred psi? It's been my experience that no matter what fill I have I can dive as long as I had planned to, and I'm a new diver, so my air consumption is not anything special. With a 2700 fill, I think most people will still be able to come as close to the ndl as the should and be back on the boat with more than 500 in the tank.

Dive shops lose money on everything. It is just a hobby they have, out of the goodness of their hearts, so folks like us can enjoy diving.

If you pumped $30 worth of gas into your car, would you be happy if the pump only delivered $27 worth of fuel?

 

[Alian1]

And for that matters, if the goal is to get people in the store, and they are already losing money, wouldnt it be better to always give good fills to get the divers to come back?

 

[ReefHound]

Short fills are always annoying but especially so on dive charters at premium dive sites. Especially when it is consistently short for everyone and clearly the result of the staff just rushing everything through. They don't consider being off by 10% to be a big deal. I'll let anything less than 10% short slide but I wonder how they would react if I deducted 10% of the charter fee from my bill (or tip)? I got a feeling 10% short would suddenly be a pretty big deal.

 

[under water]

With a 2700 fill, I think most people will still be able to come as close to the ndl as the should and be back on the boat with more than 500 in the tank.

Hi Jeff,
Not true for me. I might be considered an air hog. I ALWAYS run out of air long long before I approach any NDL limits, especially if we are talking NITROX.

 

[Cacia]

2800 and I whine. I liked it better when my gauge was broken and I always believed I had 3300 and that everybody loved me.

 

[SparticleBrane]

Aluminum, over 10 years old, sorry can't fill those. Steel, sure let me put 2 or 3 burst disc in it and then it won't have a limit.

Do you have any credible basis for rejecting aluminum tanks manufactured in the early '90s? Could you identify the shop where you do this?

Sarcasm...

 

[J.R.]

Here is my understanding of how short fills happen from my son who works in a dive shop...

There are cold fills and hot fills...

When the tank is a hot/fast fill, it will register as being full, even up to 3200psi... thus when the tank cools down it now becomes a short fill at 2800psi.

When the tank is a cold/slow fill the compressed air has a chance to cool down and compress even further. A cold fill that takes a few hours to do will result usually in a full tank at 3000psi.

So it probably is the situation with most LDS and dive boats that they are doing a hot/fast fill and to them, it looks full. Thus cooling down later or when hitting the water the air pressure drops.

... question...

Years ago I remember dive shops set the tank to be filled in a 50 gal. drum of water while filling... today all I see (although this is a limited sampling) is "set the tank on the floor, attach the whip... hit the air"...

Would putting the cylinder in water during the fill help with a full fill by acting as a heat sink? "Back When", I seem to recall they did it "in case the tank ruptured"... but that was 30 years or so ago...

Is there any reason they don't set the tanks in water these days??? Safer tanks? Better inspections? Just curious...

 

[fishb0y]

You're gonna get a couple answers on that one... My belief, the temperature differencial between the tanks and water isn't really enough to effect the temperature of the tanks. Second... if a tank were to rupture, not only would your body be mangled, you would also be wet. I'm sure you would see plenty of "Professional Tank Fillers" yelling that I am wrong...