I have some APC batery backup units. They can run my tank for a few hours if hte power goes out. I have only had a need to use them once when the power went out for 4-5 hours. They are relitivy cheap and can be bought at just about any bestbuy compusa, ect. I tink it costed me about $150-$200 for a 2 hour run time with everything except the lights on.