How do you properly bleed air out of nitrox tanks

[tursiops]

Invest in a tank muffler if you drain tanks often.

A towel wrapped around the valve to muffle the sound works pretty good.

 

[BoltSnap]

If you have to drain the gas out of the Tank, do it slowly as not for any condensation to form inside the Tank. The condensation is bad for Steel Tanks especially.

For those that say rapid draining the gas out of the tank is not an issue, you are wrong! Condensation of water vapor WILL occur and water will accumulate at the bottom of the tank if you let the gas out rapidly. This is NOT good especially for Steel tanks! I know this for a fact from experimentation and even when using new filters in good condition in the compressor.

 

[johndiver999]

Nothing special needed. 40% is about as safe as air, regardless of what CGA and other handwringers say.

No need to worry about moisture - the gas in the tank contains only traces of water vapor so there nothing to condense if you dont go all the way empty.

I used to think the exact same thing and after rather rapidly draining a steel tank in order to get a VIP, there was a lot of water in the tank.

I always assume that even if there was cooling and condensation (from rapid release of the presumably dry air) that subsequent filling would rapidly result in the re-evaporation of the previously condensed water. The rust in some steel tanks has somewhat convinced me that this "assumption" may not be valid either.

 

[happy-diver]

I empty slowly in the sun with a towel, open the valve a bit more when the flow stops, the last bit upside down.

The bad hydro guy that doesn't dry the tank brings the rust

A quick empty makes wetness and coldness inside and out

Whether you empty the tank, completely, or not completely

That is the question!

Well how do I know, have you seen Honey, I shunk the kids

 

[Still Kicking]

I used to think the exact same thing and after rather rapidly draining a steel tank in order to get a VIP, there was a lot of water in the tank.

I always assume that even if there was cooling and condensation (from rapid release of the presumably dry air) that subsequent filling would rapidly result in the re-evaporation of the previously condensed water. The rust in some steel tanks has somewhat convinced me that this "assumption" may not be valid either.

If you rapidly drain a tank all the way empty, yes you can get condensation inside from vapor in ambient air.

I let the tank warm up to room temp before draining all the way or immediately put it on a hot air dryer (quicker).

 

[grf88]

I made a simple muffler that attaches to a BC hose. It is a piece of capped ABS tubing with multiple holes drilled in it and filled with plastic pot scrubbers. It has a BC nipple at one end. Since the 1st stage acts like a one way valve no ambient air can enter the cold tank to cause problems with condensation. It is also very quiet.

 

[Manatee Diver]

t is a piece of capped ABS tubing with multiple holes drilled in it and filled with plastic pot scrubbers...It is also very quiet.

 

[grf88]

View attachment 680775

Good job I didn't make it out of iron pipe.

 

[johndiver999]

If you rapidly drain a tank all the way empty, yes you can get condensation inside from vapor in ambient air.

I let the tank warm up to room temp before draining all the way or immediately put it on a hot air dryer (quicker).

Well, it was my conclusion that the water was in the tank the instant it was opened up, there was no introduction of ambient air - or not enough to allow measurable water. Drain the steel tanks slowly

 

[grf88]

Well, it was my conclusion that the water was in the tank the instant it was opened up, there was no introduction of ambient air - or not enough to allow measurable water. Drain the steel tanks slowly

Scuba air should have a very low dew point much lower than you would get from the adiabatic cooling of the tank. Maybe in warm locations this is not too important but in cold water locations it can result in serious problems.