I just finished my Nitrox Cert class and wanted to find out what shops fill Nitrox. One LDS said they would be glad to fill my tank, however I had to bring it in empty. I know you never empty the air in your tank. Is this a palce I should stay away from?
NITROX Refills
- Thread starter ccso434
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lifeisfullofgooddives
Contributor
Most shops I know in Florida have Nitrox. The only place I know of that doesn't is Diver's Direct.
What you want to look for is a sheet stating when the last time their fill stattion was inspected. I know at the shop I go to they have the sheet sitting right where you sign out your tanks. On the sheet you should see an air quality reading. This is there to state what grade of O2 they are using as well as how good their filters work.
If A shop doesn't have it out you can ask for it, if they won't show it to you...well you might not want to get your tanks filled there.
but that's my 2 cents
What you want to look for is a sheet stating when the last time their fill stattion was inspected. I know at the shop I go to they have the sheet sitting right where you sign out your tanks. On the sheet you should see an air quality reading. This is there to state what grade of O2 they are using as well as how good their filters work.
If A shop doesn't have it out you can ask for it, if they won't show it to you...well you might not want to get your tanks filled there.
but that's my 2 cents
They must partial pressure blend (mix the gas in your tank), so the tank needs to be drained for accurate formulas to get the right mix. If there's gas in the tank, it would change the formula for the mix you want. It's not uncommon to have to bring in empty for places that partial pressure blend. You should be sure you let all of the gas out through the valve slowly bleeding it off, don't just crack them open to full...ccso434:
If you get nitrox someplace that banks it (pre-mixed nitrox) - then they wouldn't require you to empty the tank.
Uh, Lifeisfullofgooddives, are you responding to this guys question?
CCSO, if that's your only option, I wouldn't worry about it. They just don't want to use their HP O2 (or they don't want to screw with the math). For example if you brought in your tank with 1500 psi, they'd have to use an O2 tank with say 1600 psi to give you EAN32 instead of their nearly empty tank with only 200 psi.
CCSO, if that's your only option, I wouldn't worry about it. They just don't want to use their HP O2 (or they don't want to screw with the math). For example if you brought in your tank with 1500 psi, they'd have to use an O2 tank with say 1600 psi to give you EAN32 instead of their nearly empty tank with only 200 psi.
I suspect they only want it empty for the first time they fill it for you... unless it is o2 clean?
Regardless, just bring it in with 300 psi and tell them to go ahead and empty it if they need to.
Regardless, just bring it in with 300 psi and tell them to go ahead and empty it if they need to.
PerroneFord
Contributor
It could also be they are cascading oxygen and don't have a booster pump for it. Thus in order to get the oxygen to flow into your scuba tank, they have to drain it down first. No, you should NOT empty your tank. 200psi should do fine. If they can't cascade to 200psi, they need to replenish their tanks or buy a booster pump.
Most shops will ask you to empty it first. If they do a blend, they need to begin with an empty tank for the proper mix.ccso434:
Actually, that's also true if they use the denitrogenating process (filter out nitrogen through a membrane). Either way, they'll want the tank empty (20-100psi is fine... as long as there's just a bit of positive pressure).
I'll accept that filling from lower pressures of O2 is an acceptable reason for wanting a tank bled (mostly) down, but although I don't fuss, not wanting to do a little math to get the proper mix annoys me.
Now, if it's not being *able* to do the math to get the proper mix, I would be more than happy to hire myself out as a "Physics and Mathematics Consultant" for the low, low price of... say... 20 free fills, and if that's even too hard, I'll custom write a tiny applet for, say, one jumbo-D O2 cylinder for the recreational nitrox version.
Now, if it's not being *able* to do the math to get the proper mix, I would be more than happy to hire myself out as a "Physics and Mathematics Consultant" for the low, low price of... say... 20 free fills, and if that's even too hard, I'll custom write a tiny applet for, say, one jumbo-D O2 cylinder for the recreational nitrox version.
also alot of places want to do more than one tank at a time.. its easier to belend 4 or more tanks at once than do them individually.. this way you empty the tanks and blend all at once..
If I have one tank to do, I'll just mix on topof the old one, but if I'm filling alot of tanks, they all get emptied.
If I have one tank to do, I'll just mix on topof the old one, but if I'm filling alot of tanks, they all get emptied.
BabyDuck
Contributor
eh, just dive the kludge mix. as long as you're analyzing, and not doing a dive where a specific mod matters, close might be good enough.
or go where they bank. that's the easy answer!
or go where they bank. that's the easy answer!
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