[Sk8r]

Suggestion: instead of trying to provide full power for a transient power outage, get a Penn-Plax bubbler pump: they're small, cheap, and they can be rigged to come on to power an airhose and bubbler somewhere behind the rockwork. They'll last as long as you have batteries to feed them. For big weather problems, yes, a generator; and you're where there can be extended outage; but for the minor ones the little bubbler can keep fish breathing well enough. They're a good option for everybody to have, at least in the house.

Most tanks can go 8 hours with no power, no problem. Beyond that, things can get iffy, and among precautions for a long workday stint or a weekend at the beach, these might help, running on regular power most of the time, but switching to battery in a power-out. In general, bubblers aren't a useful item in a reef, and not something you want going on long-term; but if you live where power is a dice throw, and you have to be away for 3 days, this is a good bet. Just keep bubbles away from fish and corals as a rule.