Diving old air in your tanks

[lowlysubaruguy]

I have a buddy in Florida who stores our tanks for us when were not there. Usually 6 to 9 months between dives some years maybe longer depending on where we might go instead of Florida at what time line. My wife’s tanks maybe longer because I tend to get cranky if I have been. In the water in 6 months. I know because its been just about 6 months for me right now and I’m thinking like Jack Nicholas in the shinning some times.

Often our tanks have just sat there with air from when he filled them from our last dive. I can ask him to use them there the same sized tanks he dives with so he probably should and keep the air fresh if thats the best thing for them. Should these tanks be dumped and refilled or even dumped cleaned and inspected before we come down for our dives. I dont know how air or even the tanks react when just sitting. I have to assume the air is not free of things that might not be great for you.

I know for a fact I’ve rented tanks that made me feel like crap at the end of a dive or at least I’m thinking it was related to the air Ive had some that literally had an off taste to them even. Maybe from the compressor or the filtration was in need of service what happens when a tank of something like that sits around for 6 to 9 months. Any thoughts?

 

[michael-fisch]

If the compressor's filtration is in order, what goes through it can be breathed and stored for many years - I wouldn't worry.
Where you have to watch out for is some operators try and save money by using filters long past the point where they should have been swapped.
BTW A relatively new filter can turn poison gas (Sarin, VX) contaminated air into something that is perfectly ok to breath.

Michael

 

[happy-diver]

I think I'd feel more comfortable drinking my own urine

 

[clownfishsydney]

The only problem is if they are steel and have water traces in them, the rusting can create CO2 and use up O2. If aluminium, should never be a problem. I would not consider this worrying about.

 

[Thomas gray]

When storing tanks for a long period of time (3 month or more). Leave a little pressure 200psi to keep moisture out. Now for storing full tanks and using them six months later It should be fine. Just make sure to visually inspect tank before using.

 

[DeepSeaExplorer]

If it makes you feel better, put an analyzer on it and confirm proper O2 level.

 

[PfcAJ]

It’s fine.

 

[GreggS]

Ours will sit full over the winter, usually up to 6 months between dive seasons. Never had a problem with them. Ours are aluminum tanks.

 

[broncobowsher]

The only problem is if they are steel and have water traces in them, the rusting can create CO2 and use up O2. If aluminium, should never be a problem. I would not consider this worrying about.

False, where does the carbon come from? Fe + N2 + O2 is all there is inside the tank. The trace amounts of carbon in the steel won't amount to anything. We are talking trace amounts of carbon, the steel tank will rust and blow out long before the amount of carbon means anything. You can't make CO2 without having a source of C.

Find a local rebreather diver and look at there bail outs. Especially there deep bail out. The inspection sticker is often expired by several years and not surprising if the hydro is expired as well. The gas is still tested and is fine. But since it isn't used in a dive as long as everything goes right it can be years between refills.

 

[ThatDogDontHunt]

Old air in tanks.

Bleed old air from tank?