Yeah I was confused also. *Your best bet is to post the overflow model or if you have a picture. * *If power went out you could take a small air hose run it up to top of the overflow tube and suck up the air with out drinking that is, and that will get the overflow going again. *That's based on the assumption that you're talking about a normal overflow.
The aqua lifter pump is the best pump choice for pulling the air out and restarting the u-tube syphon should it break/ loose syphon. The method of using the air line to manually remove the air the first time is great for the initial start. In most cases once you get the syphon started you are good to go even when the power turns off. That is assuming the use of a properly designed HOB overflow like your Eshopps one is. Basically as long as both sides of the u-tube stay submerged then you will not loose syphon. But most people also find that overtime bubbles will build up in the top of the u-tube and that eventually the bubble gets big enough that you loose syphon anyways. This is where using the aqua lifter to constantly draw out the air really helps. I must stronly suggest that if you do use the Aqua Lifter pump method that you make sure to keep the output of that pump submerged in the overflow. I keep mine in the outside box. Do not leave it exposed to air as this will cause the syphon to break during power failure occurances by allowing air to back travel back into the u-tubes. I also do not suggest having the outflow of the pump drain into the sump as this can cause a continued syphon thru the pump even with the power off to the pump.
Alright thanks for all the help. Yeah I tested turning the power on and off again a few times and I didn't lose the siphon. Just gotta keep an eye on it I guess. My friend gave me a scare about it. Was a little confused but all is good.