There are three different way of backup for power outage. Basic is a pennplax air pump that runs on c or d batteries automatically when power goes out. this is only for water movement/aeration. These can run like 10-12 hours on fresh batteries. Then there are battery backups for like computers. these can run power heads for movement/aeration and small filters, maybe not heater though unless it is small. There are ways to calculate your electric use for your emergency equipment vs how much run time you get out of the UPS. We call it Watt hours, or W/h. Then there is full blown generators/inverters that are gas/propane/nat gas powered. These are generally expensive, need to run outside, cause its a motor. And depending on what you want to run, you can go balls to the wall with a massive one and run your tv, computer, tank, and maybe fridge. or smaller one that can run your whole tank and lights, again looking at your W/h needs will determine what you want to run/can afford to run (vs cost of backup system) and for how long.
