[Delphinus]

I think my tank has gone as long as 8 to 10 hours flatlined due to a tripped breaker when the house next door was being built. Everything survived although I was sure upset to find out about it.

Also have routinely suffered power outages over the years although rarely have they ever been longer than 30-45 minutes. IMO those aren't too bad.

The real type power outage you have to worry about is when the electrical grid goes down like in '03 in the east (I was there for that, fun), or weather related things (ice storms, hurricanes, whatever). And then your only real hope is a generator and enough fuel to last you through. Although I suppose battery operated heaters and air pumps may help you limp through the event.

To me (and this is by no means a definitive list), my concerns would be prioritized like this:
- (if there is a sump), make sure the sump can handle the extra water volume when the sump return pump is shutoff and there is backflow from the main tank
- O2 saturation, without water agitation from the sumps, the O2/CO2 exchange can be impeded; but if you think about it, this isn't going to become a problem instantly.
- temperature, it will drop. Again though, not an instant problem, because it will take a long time for water to shed the degrees. If the room temp isn't much lower than the tank then that should help slow it down too.
- as for being in the dark, this is less stressful on animals than being stuck in a lights-on situation (which is much more stressful IME).
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