Power out

Depending on the tank size, there's no need to panic.
I've lost power in the middle of the night(Thunderstorm) and the tank went without power for ~6 hours and it was perfectly fine.
 
The most important concern with short term power out is loss of oxygen. Depending on the tank this can happen in just a few hours. I recommend that everyone have a battery powered Penn Plax B-11 set up for every 2 ft of tank length. This pump can sense the loss of power and will then turn on, pumping for several days on a pair of fresh batteries. Large fish are the first to die. I go into this and all the other things that can take down your tank in a series of articles I wrote a while back (Stopping Murphy in His Tracks):

http://reefkeeping.com/issues/author/gh.php
 
Back
Top