im thinking you are in DWC correct?? if so i have had my power out for several hours (like 8-10) at a time with no problems. i would change out the water every 12, hours at the latest, as new water has new oxygen in it. technically in dwc you dont even need the air pump but you would be changing out water constantly. or another thing you could do is lower the water level and only leave about the bottom 2" of water in your res/bucket that should work ok for a while to.