These saved my fish during a power outage. I run sponge filters so this was perfect...they are a bit noisy but exactly what you would expect from a battery powered air pump.
I hooked it up and tested it when this latest wind storm started. I ended up not needing it but was glad I had it ready to go.
When my power recently went out this pump worked well as expected. I used just one in my 55 gal. tank, with lots of fish in it, for a day and a half and didn't loose a fish.
3 day powe outage? Annoying and uncomfortable, but no longer panic-inducing. I lose 1 fish to the cold, and the rest hunkered down, with enough oxygen to survive the storm. I just got a 2nd one in case I have quarantine tanks set up during a storm. Pair these with the never-clog airstones, an emergency blanket, a few heat pads and a stash of D batteries and you're good to go!
Ordered one in the aftermath of Hurricane Florence.
Being from Wilmington, NC, ground zero for Florence, this was just what I needed to help get through widespread power outages.
Don't have one? Get one asap!