On Wed, 17 Nov 2004 12:48:09 GMT, Victor Martinez
wrote:

Dick wrote:
I have air bubblers in all my tanks. Never gave a thought to them as
backup to the filters. One more reason to have air in the tank.

Actually, air bubblers have a minimal impact on oxygen concentration in
the water. It's surface water turbulence that provides enough gas
exchange. Bubbles are too small and their contact time is too short to
provide efficient transfer between phases.
If your filters go out, I'd recommend a power head producing water
surface movement.

Better yet keep spare filter on hand. I have seen the bubbler help in
the quarantine tank when I briefly treated several mollies for
possible ich. They were swimming at the surface until I added air, so
it can be helpful.

dick