Need help on used AL tanks

[ChrisA]

I have someone that wants to sell me some used AL tanks. Here is what he has.

2 - 80cu AL standard tank that has been Nitrox cleaned and he says it can be used for either air or nitrox for $100.00ea
Can you use air or nitrox in the same tank??

2 - High pressure Neutral Buoyancy tank with sherwood valves for $120.00ea
How can you tell this?

each are 1 1/2 years old.

Are these worth buying for the price? I know you can buy new ones for $125.00 so I do not know if this is a good deal or if the guy is being stright with me.
Thanks

I can buy a brand new AL80 for $110. Why pay $100 for used? But maybe stuff
cost more in FL?

The High pressure tank may be worth it if you want to move some of the wieght off your belt and if you can get it filled to the higher pressure.

I don't see these as great deals but I've seen worse. I've seen people spend more than retail for used equipment. It's leat it's not that

 

[pasley]

In another incident, the result was a flame thrower. Now let me mention that I am strickly an air diver. But from what I have read, if the O2 level gets above a certain level (40% ? ) then the whole system has to be able to handle it, including the tank, valve, and regulator. Contimants in the system could result in a flame when and when you don't want one. Now take 3 deep breaths on your 2nd stage before you start the dive.

 

[teknitroxdiver]

Yes, that's right. You can use non-O2 cleaned items up to 40%. Above that you need O2 cleaned parts. Basically that means different O rings and lubes. If you do not, you run the risk of the non O2 compatible parts oxidizing. Or burning. Neither is good, especially not the burning part, since things seem to burn much better in a high O2 environment. Hmm wonder why??

I think there's a picture around somewhere of a 40cf oxygen tank that explosively burned in the fill station. The reg and neck of the tank were completely blackened, I think it also hurt the fill monkey pretty good too. I'll try to find the picture, it's a very good reinforcement of why you have to be careful around mixes containing more than 21% O2.

 

[jlwest63]

Thanks for all the info. New tanks here are 124.00 +tax and for the NB 3300 it is 145.00 plus tax. Then add another 20.00 per for the cleaning. Come to find out they are less then a year old. I will probably have them checked out and if all is good go ahead and get them. Thanks for the info and letting me know what to look out for.