I am confident my tanks can survive about 24 hours, summer/winter, without power, but anymore than that, I will be scrambling for a generator!
A propane generator is on the top of my needs list, not my SW list, but all lists.
Like most everyone here, I have a great deal of money and time into fish/reef keeping, I also never forget these creatures are my responsibility.
We have a very outdated, fragile and over loaded power grid in this country! This has always been a concern, not just for my reef's, but also for my family.
Good reminder, thanks!