using pure oxygen can actually be dangerous to the fish if you cause super saturation of the water. The use of pure oxygen is generally left to the commercial operations and experts who need to keep large fish loads in water that can't possibly hold enough oxygen trough any atmospheric aeration method. Using pure oxygen is generally costly and probably not appropriate for a backyard scale system.
I believe if you are going to use bottled oxygen in a system you want special diffusers and the goal is to make the bubbles small enough that they never actually break the surface since any of the pure oxygen that makes it to the surface will be lost to the atmosphere and thus a waste of money. Just having a couple of small oxygen bottles isn't really going to do you any good long term other than perhaps having it for a backup in case of extended power failure or if you ever need to bag some fish with pure oxygen for shipping or transport.
Pure oxygen may be a good thing to have handy in case of a power failure. I wonder if anyone has done calculations on how much you need per pound of fish per hour for life support. My fish supplier pumps it into the bags I get my fish in so even surface absorption might support them.
Yea, when bagging fish for transport, it is often really handy to fill the bag with O2 instead of just air.
Or if you have to transport fish during hot weather, being able to bubble small amounts of O2 in from a bottle may be handier than a regular air pump but you should research it carefully since bubbling O2 into your water should be done with a full understanding of what you are doing and how to do it safely. Also, one should be careful around tanks of O2 since it makes fire dangers greater.
I'd save them for a Nitrous oxide party!...wheeee!
Patric, you may already know....just an fyi for any thinking about doing this.
I use oxy tanks when I braze @ work.... Those tanks can have up to, or slightly over 2,000 pds of pressure. You need to make sure you have the proper regulator. You can get 'low flow' ones for the medical tanks.
TCis right...pure O2 is nothing to play around with...it can and will start fires with no ignition source.
Lower cost and safer oxygen concentrators can also be had or built for industrial uses including aquaculture. Concentrators should not be confused with generators and once people understand the differences between the two and between aBsorption and aDsorption the safer working with gasses and aires can begin. I think.