The two times I lost power for an extended period of time was for 4 and 5 days. During that time I had only my vortech with a DIY dry cell car battery. The second time was a little tougher since it was cold outside but I got through both event with no losses. IMO you only need to run a pump to oxygenate the water and you'll be fine. I agree with everyone who said your best bet will be a generator for long term outages.
