On the subject of battery backups, I got an Enercell 90W portable inverter for $8 online. It isn't the most efficient unit, but it comes with a 4Ah battery inside and one outlet. I tested it out and it powered a Koralia nano (425 gph) for 6 hours before it ran out of battery. A lot cheaper than the Vortech backups, though it won't last as long. At this price, it is probably a modified square wave, but I didn't notice any strange cycling of the pump and it didn't heat up at all, so I'm fine with it. I'd rather drop in a powerhead during a blackout than an airstone. Plus, the unit can be charged with either AC or DC power, so I could add an extra 12V deep cell battery to extend the amount of time it could run during a blackout.