I don't worry about air in the line. It pushed its self out once power comes back on. But my tank has a big backup battery. I can run my tank full power including heater pumps skimmer lights ect for over 2 hours. I have 2 Power supply's on my apex that turns things off if power is out. Only thing that stays on is one power head low power, return pump low power as its a DC12000 converted, heater only if temp drops below 74 (normally 77), skimmer will run on for 1 hour then off for 3, lights off, dosers off, second powerhead off. With this way I get about 12 hours time.