It says right on my tanks - DO NOT OVERPRESSURIZE

[Ted Judah]

A year ago, I bought tanks for my wife and I. In that year we have used them on 16 dives and had them filled at 5 different dive shops. The pressures after each fill seem to vary wildly and is often overfilled.

Here are the markings on the tanks:

FABER MADE IN ITALY M8303 21/0154/ 073 02•21+
TC - 3AAM - 184/DOT - 3AA2400 DO NOT OVERPRESSURIZE REE67 BS85S


Below are the start fill pressures for each dive:

2400 lbs.
3400 lbs.
2600 lbs.
2500 lbs.
2500 lbs.
2500 lbs.
2200 lbs.
2800 lbs.
2800 lbs.
2800 lbs.
2950 lbs.
2400 lbs.
3000 lbs.
2750 lbs.
3250 lbs.
3525 lbs.

Am I missing something? should I be concerned? Should I request a certain pressure from dive shops?

 

[Manatee Diver]

In that case to be “proper” just get a bigger tank. They do, and then they overfill those too and that new extra amount of gas becomes part of the regular dive plan, and so on.

Then we start adding stages. Just short of 500cuft in the photo.

Expensive dive, and I didn't even find what I was looking for.

 

[Bearded Diver]

There is an argument that super high pressure cave fills provide better margin of safety.

So lets say you get a 4,200psi fill. That gives you a 1,400psi third for penetration. But that means that third is is from 2,800psi to 4,200psi the pressure at which Z factor means you get less actual gas for the given pressure. So that means you go through it more quickly as you still need the same amount of gas to get IP.

Now this is one of stupid post dive arguments you have while waiting for dinner because we are probably talking maybe a few percent difference. And 4,200psi cold is very very hard to get.

Could you please specify what IP means? Thank you

 

[Bearded Diver]

Then we start adding stages. Just short of 500cuft in the photo.

View attachment 790396

That’s a pretty spring

 

[Manatee Diver]

Could you please specify what IP means? Thank you

Intermediate Pressure, it is the pressure that the first stage delivers to the LP side if the reg.

That’s a pretty spring

Ginnie is very pretty when the crowds die down. That was taken in late August.

 

[Bearded Diver]

Intermediate Pressure, it is the pressure that the first stage delivers to the LP side if the reg.



Ginnie is very pretty when the crowds die down. That was taken in late August.

Always wanted to dive Ginnie Springs. May I ask what the temperature was on the bottom in late august. I’m aware the springs are cold, but I imagine it’s slightly “warmer” temp (water) during the summer? Tia

 

[rx7diver]

... I look forward to acquiring old tanks made well before I was around sicne they not only look cool, some are reasonably priced and are overfilled by the cavers all the time. Happy diving.

I wouldn't recommend overfilling these old 2,250 psig 72's. I never ask for mine to be overfilled beyond its 2,475 psig plus-stamp. However, it sometimes gets filled to 3,000 psig (because some shops around here have their fill stations set up to fill Al 80's, and sometimes people neglect to check, I think). I never complain, though.

"New" low pressure steel (3AA) cylinders are commonly 2,640 psig (= 2,400 + 10%), and seem to be engineered a bit stouter.

rx7diver

 

[Manatee Diver]

Always wanted to dive Ginnie Springs. May I ask what the temperature was on the bottom in late august. I’m aware the springs are cold, but I imagine it’s slightly “warmer” temp (water) during the summer? Tia

72 degrees all year round. The spring run might be a degree or two warmer or cooler.

 

[Eric Sedletzky]

I wouldn't recommend overfilling these old 2,250 psig 72's. I never ask for mine to be overfilled beyond its 2,475 psig plus-stamp. However, it sometimes gets filled to 3,000 psig (because some shops around here have their fill stations set up to fill Al 80's, and sometimes people neglect to check, I think). I never complain, though.

"New" low pressure steel (3AA) cylinders are commonly 2,640 psig (= 2,400 + 10%), and seem to be engineered a bit stouter.

rx7diver

I love it when they fill my 72’s to 3000. I keep my mouth shut.

 

[James79]

I love it when they fill my 72’s to 3000. I keep my mouth shut.

I prefer to run mine at 2800... The occasional 3000 or 3100 never hurts my feelings, though!

 

[Eric Sedletzky]

Then we start adding stages. Just short of 500cuft in the photo.

Expensive dive, and I didn't even find what I was looking for.

View attachment 790396

That spring looks beautiful! Too bad it’s 3000 miles away compounded by the fact I don’t have any cave training