I bought two of these kedsom ones for each tank. Has 2 lines and says runs for 24 hours. Plugs into an outlet and comes in when power is lost. I’ve unplugged it and it comes on a couple seconds later. Don’t know about duration yet. But should help if I’m not around.Ice and snow not a problem here, but hurricane season is. Did not have a salt water tank set up last time power went out for any major length of time. but I used the air stones from Walmart for minnow buckets. The small ones can run 12 hours on 2 AA batteries. larger ones take C batteries I think.