I have a air check valve on the top of the of the first tube plus I have a hole drilled into the pipe right below on the water line on the return pipe as well hopefully this will stop that from happening. But on the skimmer stuff you think it's ok I don't need to rebuild it? You r right the chamber where the skimmer is the water level will stay the same unless water from the main tank overflows from power outage. But like I said I will have a siphon brake their.