Help filtration

[cjml]

Hello! We went from a single hang on the back overflow to a dual hang on the back overflow and now if the power goes off we lose siphon.Its almost as if the dual lines are evacuating the water from the spillway too fast during a power outage. we have adjusted the depth of the spillway repeatedly with no luck.
All help greatly appreciated! Thankyou!
ML

 

[bot587]

consider a small generator incase power does go out. You should try and set it up through gravity though (defeats hassle of electricity)