Quote Originally Posted by MartinP View Post
So the inert gas would need to totally replace the air inside the top of the container, in order to be effective? One of my colleagues is mis-using the stuff, oops. Though perhaps the diffusion of the smaller volume of inert gas takes some time (more than the time between weekends anyway)? I'll stick to marbles and squeezable bottles I think.
The Argon settles to the surface of the developer because it is heavier than Oxygen. People use this in preserving paint and varnishes, and a brief spray is all that is needed. I've been using this for two years now and have had no developer go bad in an opened container.

From the Bloxygen site:
The heavy, inert Bloxygen gas sinks down to block oxygen from the liquid surface. Because Bloxygen is heavier than air, it will separate the liquid surface from any air that may remain in the container.

BlOxygen has a suggested retail of $10.95 to 11.95. Each can is good for about 75 uses in quarts, 32 uses in gallons.

Hold container lid/top closely above opening of the container to capture the gas blanket.
Spray inside for 2 full seconds (quart size or less)
Spray inside for 4 full seconds (gallon size or more)
Replace lid on container immediately and capture the gas blanket. The gases now settle on the surface to prevent loss through drying and hardening.
Each can of BLOXYGEN provides over 150 seconds of protective gas.