[jagermaier]

Originally Posted by Reef Pilot

Depends on time of year. Where we live, power outages tend to happen in late fall and winter, and the house will cool more quickly. 5 or 6 hours is no big deal, but after 12 hours there could be harm to your livestock, especially your fish. So you will definitely want to operate your heater after 5 hours, IMO.

That's why I like a battery inverter, to operate pumps (intermittent and low setting) and heaters. And it has enough capacity for 12 hours and more, depending on what you have. I can add an RV battery (or car battery) to mine to more than quadruple its capacity if I need to. I had to go through this a couple years ago, when our power was out for more than 24 hours. Everything survived just fine, and fish and corals did not suffer in the slightest.

I actually use this equipment during the summer at our lake cabin, charged by our solar panels. Then I just bring it home in the fall, and use it as a power back-up for my reef tanks. So no extra cost for me.

Obviously for long outages especially in winter heat becomes a concern. Water retains heat fairly well so if you cover your top so should be good for most power outages that are only a few hours long. I have yet to experience a power loss longer than that!