Water inside your air tanks...

[dschulte]

Today I took two of my steel tanks to be O2 cleaned for NITROX. The first was a brand new tank, never filled. This one passed the visual inspection with flying colors of course. The second was an identical tank that I have dove about 6-8 times since I purchased it back in July. To my shock and horror, when the valve was removed and a visual inspection made, two tablespoons of rusty water were found pooled in the bottom of the tank. The inside was covered with flash rust. I was at the shop when this was inspected. I brought my other two steel tanks, both about four months old, in from the van and had them looked at. We drained them, pulled the valves and found the same thing, the inside covered with rust! My tanks have never been lower than 300 psi and were purchased brand new. I was present at all three of the initial fillings and saw that the insides were spotless when purchased.

I have talked with several experienced friends and none of us can come up with a reason for this beyond bad air fills. The only way to get water into a tank is to either let it empty completely, not drying out the DIN prior to filling or an issue with the fill station. Before I point any fingers, does anyone else seen this happen? These are new tanks, the oldest is five months old, and the youngest is just over two months old. All purchased new and spotless. I have around 40 dives on the most used, and 8-10 on each of the others.

Any feedback would be greatly appreciated.
:lurk2:

 

[FlynDive]

Today I took two of my steel tanks to be O2 cleaned for NITROX. The first was a brand new tank, never filled. This one passed the visual inspection with flying colors of course. The second was an identical tank that I have dove about 6-8 times since I purchased it back in July. To my shock and horror, when the valve was removed and a visual inspection made, two tablespoons of rusty water were found pooled in the bottom of the tank. The inside was covered with flash rust. I was at the shop when this was inspected. I brought my other two steel tanks, both about four months old, in from the van and had them looked at. We drained them, pulled the valves and found the same thing, the inside covered with rust! My tanks have never been lower than 300 psi and were purchased brand new. I was present at all three of the initial fillings and saw that the insides were spotless when purchased.

I have talked with several experienced friends and none of us can come up with a reason for this beyond bad air fills. The only way to get water into a tank is to either let it empty completely, not drying out the DIN prior to filling or an issue with the fill station. Before I point any fingers, does anyone else seen this happen? These are new tanks, the oldest is five months old, and the youngest is just over two months old. All purchased new and spotless. I have around 40 dives on the most used, and 8-10 on each of the others.

Any feedback would be greatly appreciated.
:lurk2:

Hey, I just bought a 119 HP steel at Diver's Supply and I noticed it had no pressure when I went to fill have it filled two days later. It is a new XS Scuba Worthington tank. The Macon store was out of stock so I got it from the Marietta store. Maybe I should have it looked at, it's full now, I'll check on it soon. Just wondering where you got yours.

 

[mike_s]

Have you gotten all the fills at the same fill station? (was it the one that you were at when they discovered it?)

It sounds like to me moisture from the fill station.

 

[NorthernShrinkage]

the flash rust is exactly that flash from the time it is 02 cleaned until after you take it off the dryer it will have a light coat of rust there are products out there that will prevent this but its realy no biggy . as for the water in the tank one of 3 things is happening in my opinion either the tanks are not being dryed properly at the shop before the valve is replaced , your getting bad air fills , or the tanks are being drained to low or to quickly any of these will cause water build up .

 

[dschulte]

Have you gotten all the fills at the same fill station?QUOTE]

Two of the three solely at one fill site, the other tank at two sites. The site that found the issue is not the one where 90% of the fills occurred.

 

[fire_diver]

the flash rust is exactly that flash from the time it is 02 cleaned until after you take it off the dryer it will have a light coat of rust there are products out there that will prevent this but its realy no biggy . as for the water in the tank one of 3 things is happening in my opinion either the tanks are not being dryed properly at the shop before the valve is replaced , your getting bad air fills , or the tanks are being drained to low or to quickly any of these will cause water build up .

It's most likely bad air fills. I don't care how fast you drain a tank, it won't form condensation if the water isn't there in the first place. My air fill station test to -95 degrees for condensation. Maybe if I just open the valve all the way with a full fill I MIGHT get close to that number. Even then, that's to get ANY moisture to stick to the walls. If you're pouring water out of a tank, someone really screwed something up. My guess was a dive shop.

FD

 

[kidspot]

Do the shops use a water tub for cooling, or do they fill in a dry environment? My understanding is that one of the reasons shops are moving toward dry fills is there is less chance of water getting into the valve prior to filling (via splashing etc.)

Just something to consider.

Aloha, Tim

 

[Packhorse]

I always hear that if you drain a tank to quickly you will get condensation inside. I ask how does this happen and they say it just happens. But as fire dancer says its not going to happen unless the air is moist to begin with. Or you drain a tank quickly, it gets cold and you remove the valve while the tank is still cold. This will allow moist ambiant air to enter the tank. I doubt this is the OPs problem though.

 

[Bob3]

It sounds for all the world like somebody hasn't been changing the dessicant in the compressor's filters on time.
I watched water run out of a fill hose once, it was just removed from my tank. I was so ******* that I couldn't even chew the guy out; I was totally speechless.
That shop *may have* never filled another tank after that, I spread the word, after I got my voice back.
In the event someone stores a bottle with that much water in it for several months (like over winter) the developing rust can eat up enough O2 to be fatal to the guy diving it.
Have a serious chat with whoever filled your tanks.

 

[Gez Ward]

sounds like bad fills ,take this up with the lds ,if no joy ask yourself what else do they let slip and go somewhere else.