How soon do you refill your air tanks?
- Thread starter Reef_Haven
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Depending on time of year and climate I'm in I either dive once a week or once every 2 weeks, with two time periods of maybe a month between dives. So I try to have them filled ASAP and ready to go. My 50+ miles from the LDS here at home is also a factor.
OldNSalty
Contributor
I think the question might be a little...skewed (not sure if that is the word I am looking for)
If you are talking theory then I would think the filling/draining/filling is going to affect the tanks more than just sitting at full.
In practice, having them sit at full might do more damage for a specific set of tanks for a specific diver. The reason i suggest this is that say you make 500 dives on a tank in 5 years. How you store them isn't going to affect the number of times you get them filled (500 in this case). You aren't likely to go out on Wed to drain your tanks so you can get 'fresh air' in them before Saturday's dive.
As for the manufactures recommendation, I didn't know that it was recommended to store them at a lower psi. Sounds reasonable..but I don't always do that.
drl
Contributor
We dive nitrox, so we usually get tanks filled when we know where the next dive will be, so we can get the appropriate mix for that dive.
Being an avid diver, I not only fill as soon as I use my tanks, but also leave them at the LDS to pick up when I'm ready to dive either there or at a shore dive nearby.
soltari675
Contributor
Interesting. I didn't know about that recommendation. I fill mine as soon as possible. I live a ways from my LDS, so I don't like driving there before a dive site. I like having them ready when I want them. I also thought low pressures increase the chance of them getting moisture inside? I could be wrong but thought I heard that. So I keep them stored full.
EastTNDiver
Contributor
I've not seen that recommendation either, but I'm willing to bet it's related to long term storage. My tanks don't go unused long enough to qualify for "long term" storage.
OP
Reef_Haven
Contributor
I found this FANTASTIC thread on tank storage.
http://www.scubaboard.com/forums/ta...-cylinder-long-term-storage-fact-fiction.html
It screams, STICKY, so I'll ask a MOD to do so.
I was shocked
at some of the data on steel tanks with a bit of salt water intrusion.
Results:
One cylinder that was stored horizontally with salt water at full pressure was so badly corroded internally that only 30 ml of salt water remained. The rest of the salt water had been consumed in the corrosion process. Corrosion had reduced the cylinder wall to only 1/3 of its original thickness (wall thickness before: 0.179 inches after: 0.055 inches. After only 100 days, this cylinder was corroded so badly that it was in real danger of exploding. It was not subjected to hydrostatic testing.
Lots of great data there. It was definitely an eye opener for me.
http://www.scubaboard.com/forums/ta...-cylinder-long-term-storage-fact-fiction.html
It screams, STICKY, so I'll ask a MOD to do so.
I was shocked
at some of the data on steel tanks with a bit of salt water intrusion.Results:
One cylinder that was stored horizontally with salt water at full pressure was so badly corroded internally that only 30 ml of salt water remained. The rest of the salt water had been consumed in the corrosion process. Corrosion had reduced the cylinder wall to only 1/3 of its original thickness (wall thickness before: 0.179 inches after: 0.055 inches. After only 100 days, this cylinder was corroded so badly that it was in real danger of exploding. It was not subjected to hydrostatic testing.
Lots of great data there. It was definitely an eye opener for me.
RonFrank
Contributor
For those that do not want to read a book to get a brief answer here it is.
For long term storage (more than 3 months) it is best to store the cylinders at partial pressure.
Steel tanks are much more subject to corrosion than alum.
Tanks used in Salt are more subject to corrosion vs fresh water.
If you suspect your tank has moisture in it remove the valve stem and clean and remove any moisture inside, then fill it.
Storing a tank at 3000psi is better than storing it empty.
Store a tank upright if possible.
Most alum tanks are very corrosion resistant. Steel however can rust quickly, so take precaution if needing to store over a long period.
For long term storage (more than 3 months) it is best to store the cylinders at partial pressure.
Steel tanks are much more subject to corrosion than alum.
Tanks used in Salt are more subject to corrosion vs fresh water.
If you suspect your tank has moisture in it remove the valve stem and clean and remove any moisture inside, then fill it.
Storing a tank at 3000psi is better than storing it empty.
Store a tank upright if possible.
Most alum tanks are very corrosion resistant. Steel however can rust quickly, so take precaution if needing to store over a long period.
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