Rust inside steel tanks failing visual inspection

[GROBIOG]

It could happen if the user essentially empties it and then descends with that empty tank.

Like freediving with the empty tank strap on his back? Not sure I understood you.

Or someone does it while filling or servicing the tank - usually done by a "dive professional".

Filling??? please read my post again
Servicing? How would salt water STAY in a tank from servicing? Even considering that as a possibility, I can guarantee you it's not the case, the tanks were serviced by me and I can rest assure you it was done properly.

What is your explanation?

I wasn't offering one awap, I was asking the "experts". Yours wasn't very convincing.

Unless the tank was submerged with the valve open and empty, water comes in one way; through the filling process.

Really? And how would that happen?

4 fl oz means you're getting one hell of a wet fill.

I can accept that as valid reason, but I would like someone to explain how the hell am I getting so much water into ONE SINGLE TANK out of HUNDREDS of tanks, kind of an unlikely scenario don't you think?
But forget about all that anyways, it's salt water.

Oh yeah, as awap's post reminded me, there is another way. Someone could fail to dry it out after hydro, slap a valve on.

lol, that was a funny one.

If I was finding that much water in a tank, only filled from a single compressor, then the compressor is lacking some serious maintenance.

I think your reading skills is lacking some serious maintenance, it's A TANK out of a batch of A HUNDRED, please read the post again.

I would never fill my tanks there again.

lol, "there", is where I make my living.
This is a great illustration on how scubaboard members are quick to crucify LDS, often enough, with no factual basis

 

[KD8NPB]

lol, "there", is where I make my living.
This is a great illustration on how scubaboard members are quick to crucify LDS, often enough, with no factual basis

Just curious, but what are you guys using for filtration media? MS13X or AA?

 

[NAM001]

i posted here before and can not find my post. sooo. It lkooks to me ike you are getting bad air. wet air. My first vis on my lp95's were rusty. When the shop closed down i got one of the compresser systems and found a portion of the filtering system plumbed backwords. new air in the top and "cleaned air" out the bottom. seperateed moisture just fgot pushed out the bottom into the banks. the shop worked on them (TANKS). got them back and most the rust gone. It is my guesss that the main compressor was down and the backup , miss plumbed) was used till the primary was back on line. only takes one fill of wet air. any way alight tumble and cleaning , and a treatment of oms corrostop i think. after that i started to dry the tank once the valve was put on. by that i mean that i fill to 500 and vent. The humid air n the tank being valved and hit by hgh ppo2 air contriutes to the rusting. so i put in 2-500psi and vent the tank to diilute the humidity. a fill and vent to 10 atm should dilute the humidity by 90% each time. after 3 cycles i am well under 1% from a beginning of 90+%. then i fill as normal and inspect on the next vis.

If you have access to another lds to fill i would llook into that.

 

[redacted]

Like freediving with the empty tank strap on his back? Not sure I understood you.


Filling??? please read my post again
Servicing? How would salt water STAY in a tank from servicing? Even considering that as a possibility, I can guarantee you it's not the case, the tanks were serviced by me and I can rest assure you it was done properly.


I wasn't offering one awap, I was asking the "experts". Yours wasn't very convincing.




Really? And how would that happen?


I can accept that as valid reason, but I would like someone to explain how the hell am I getting so much water into ONE SINGLE TANK out of HUNDREDS of tanks, kind of an unlikely scenario don't you think?
But forget about all that anyways, it's salt water.


lol, that was a funny one.


I think your reading skills is lacking some serious maintenance, it's A TANK out of a batch of A HUNDRED, please read the post again.


lol, "there", is where I make my living.
This is a great illustration on how scubaboard members are quick to crucify LDS, often enough, with no factual basis

When you eliminate all the likely and unlikely causes, you may have to start looking at the "impossible" events. If the tank is not emptied, then it will require some type of filling operation to introduce water into the tank. With the added information of SALT water, it is probably not the result of a service cleaning. Tell us more of the history of the tank. Was the tank used in rental? Have you pissed someone off? I have an equalizer hose that would probably hold about 4 oz and could easily be used to introduce a liquid into a tank. But I would find it mhard to believe that someone would do that to another diver. Especially when, with the same equipment, you could J-B weld the valve on the tank and not endanger some other diver.

If the tank was emptied, then it would only require a descent of a few feet to create the situation where water can enter. Perhaps a diver went OOA and used a pony or buddy to safely surface. Of course, that would mean either the diver had a way to add some pressure (that equalizer hose or even a simple adapter to connect through an HP hose) or the filler missed the empty tank and refilled it on top of the water. Unless a diver is out to get you, it is pretty hard to find an explanation that does not involve an error by the filler, which includes the dive shop.

BTW, just because a diver goes OOA and creates a vacuum in a tank does not mean water will enter. Most properly worky systems are sealed (pass a vacuum test) so a seal will still have to be compromised somewhere for water to enter. I say most systems because there are Scubapro and Atomic 2nds with a seat saver design that may easily compromise that seal. Otherwise, some other failure (tank valve o-ring) will have to occur or a valve will have to be actuated to allow that water in.

Still unconvinced. Perhaps you should ask an "expert" who makes his living in scuba retail. They would probably know but might be a bit hesitant to share the truth as it may not be flattering to scuba retailers.

 

[halocline]

Grobiog, you have a bit of an attitude problem. People here are trying to help you and all you're doing is bitching back at them.

You must realize that if the tank does not leak, there's only ONE way water can enter it, through the valve. And there's only one way anything can go in through the valve, that's if the pressure pushing it in exceeds the air pressure in the tank. There simply is no other physical possibility. If you are 100% certain that the tank was A) dry when the valve was installed and B) never run empty while submerged, then there is only one physical possibility.

You got a wet fill, accept it and move on with your life. If it really is sea water in the tank, then I would strongly suspect that it was empty underwater at some point.

 

[drbill]

Exactly. Pulling a tank too low allows water to get in is one of those old diving wives tales. For water to enter the tank due to low pressure, 2 things MUST happen at the same time, the ambient pressure containing sufficient moisture must be higher than the tank pressure AND the tank must be unsealed -the valve open or removed.

Of course in my assumed scenario the valve would have to be open. I thought that went without saying.

 

[Mike Holden]

Thanks all for weighing in on this. I don't think the dive shop is being unscrupulous about the rust existing. I'm sure there is rust of some sort, flash or otherwise (It's a nitrox tank, so I don't know how to make that call). Most of my fills have been at Jensen since they closed the Stuart store. They are a good bunch of guys that work there. The explanation of how the moisture may have gotten in the tank pissed me off. I doubt, however, that they would volunteer that, well, there was that time they maybe couldn't get filters or driers replaced on the compressor and perhaps were giving wet fills.... Maybe I will just make a tumbler and do it myself.

Ahh yes, those guys are absolutely top notch and scrupulous. I've went in there more times than not to buy something and they actually say "Yea.. you really don't want to buy that." lol I found they are more interested in getting returning customers than they are making a quick buck. So if I were to guess I would talk to them to try and figure out what could actually be happening. Perhaps make sure to always have more air in the tank than you have been thus far? To take that variable out of the equation. I really don't know I'm just kinda thinking and typing lol. I really hope you figure it out though man!

 

[Hoyden]

I think that the explanation for moisture in scuba cylinders is pretty simple - in all likelyhood, one of two things happened - either the fill station is blowing moist air or moisture in/on the valve was blown into the cylinder at the start of a fill process. If you are getting all of your fills at the same place, I would speak to the manager about it. Either they have a compressor issue or they have fill station operators who are not following correct fill procedures.