we had a power outtage about a month ago, I was scared to death for my tank! hubby had the setup hooked up to battery backup...was fantastic. We had 2 ready to go..one already hooked...lasted 2 1/2 hours...the 2nd one was on and power came on after about 4 total hours....we kept heater, powerheads and filter running..turned off skimmer and lights...worked like a charm for that shorter time but I think we are going to get a generator as well....