I have an apc brand ups1000 battery backup. I have my 75, eheim canister filter, heater, light strip, 3 powerheads, 10g hospital tank with a rena 60 filter and two small heaters all hooked up to, when the heaters aren't on, it barely registers any use, this setup should last a few hours. I also have a portable generator that can run my whole house. We had a snow storm last year and had not power for 5 days, thank god for that puppy!