This came out of a tank that hadnt even seen its first hydro.
There was so much rusty water in it that when inverted the water level was over the dip tube and water was forced out instead of air. This rust water was then forced through the 1st and 2nd stages and they now require a full service.

Time line was something like this.

Brought new
Used
Viz test done
used some more
Not used for more than a year but stored fill.
Sold then used by new owner.

According to the previous owner he always filled at the same dive shop Dive Centre Wairau Road to be precise. And always filled with Nitrox. This one was one of a pair and the second has yet to be opened.

Wow! these yours?

No not mine.

I'm guessing there must have been at least half a litre in there. Some good chunky bits of rust as well.
I strip down and look inside my twins at least once a year, and never, ever found any moisture in there.

Would be very interested to find out exactly how it got in there...

No there wasnt that much. It was an inch or 2 in the bottom of a 750ml water bottle and a little more that had been blown out when the tank was inverted. My guess 300ml total.
Anyway... Got a txt from the owner "Surface rust on bottom and 2 sides! Will need to be rolled. Other one was dry but does have some rust patches"

I talked to the original owner last night and as far as he can recall these were always treated as a pair. Both used the same day and filled on the same day.

How did the water get in there?

1. Sabotage. Very unlikely
2. Fault with the compressor that filled it.
The fact the second tank showed no water indicates it was probably a one off as opposed to accumulative on the compressor failed and all that water was pushed into the tank in one kit. Perhaps when it was first connected. Only problem with this theory is the lack of any oil at all in the water which I would expect to be present at some level.
My guess is the auto dumps

That's about how much came out of the bottle after the dive.
You probably need to add on some for what he drank during the dive

OK. Turns out according to a tasteOmeter it was fresh water.

I had a talk to Dave the Dive Doctor.
Due to lack of any trace of oil the compressor has been ruled out as the culprit.
A possibility is that the original owner breathed the tank empty, spat out the 2nd stage, dropped down a little in the water column so the ambient pressure was greater than the internal tank pressure and water flowed into the tank via the regulator. This would have happened in the lake due to it being fresh water.

Or the tank has been drained of all air and left with the valve open. After many many days and nights the tank has "breathed" in moist air as the ambiant temp drops which has condensed inside the tank and then breathed out drier air when the ambient temp has risen again.
Honestly I find either of these reasons likely knowing the original owner, but if you rule out the impossible what you are left with is the probable right?

Thoughts?

I find the first one the most likely...

I bet I can guess who's tanks they were

Isn't air pressure inside the tank suppose to prevent water/moisture away fromgetting in? Or it depends how much air you got left in your tank...?

No Milky. nothing can travel from a low pressure system into a high pressure system unless being forced into it under higher pressure.

Ergo the water either had to get in there while the tank was at ambient pressure or get forced in by a compressor.

Interesting.
I'm gonna have a pang at the tank left completely empty in a shed or something where water condensation accumulated within due to cold air but liquidified when the day warmed up. This is why (empty or not) I place a peice of tape over my tank valve and it helps keep dust out and O-Ring in.

...by the way - Hello again. Visited a while back, but thought I had stumbled upon the South Australian SODS with this new facelift. I like it - very oceanic in the colouring.

So what happens if you have water inside your tank? Do you just tip the bottle and let the water flow out or ????

Thanks for your inputs.

Or???? suck it out with a straw?

1st you need to find out where it came from.
Then you need to get it out and get a viz test done on the tank.

I don't see how it could possibly be as a result of the second stage being lower in the water than the 1st with an empty tank.. It would require the water to get past two seats one of which is being held closed by a fairly strong spring. I reckon it's faulty dumps (or inattentive filling) on a water trap. No oil in the water doesn't rule that out IMHO..