As long as it isn't to cold and the tank isn't over crowded, I would say that 12+ hours shouldn't hurt anything that bad. I had a 9 hour outage on my 50 g tank years back and only lost one coral. I have even had fish shipped to me that got delayed for almost two days and only 1 out of the 10 fish died. Corals would be more of a concern, they don't tolerate a lack of water movement for very long. Each is different but I would guess you could see stress in them within 8 hours with no movement.
|