Who has experience with a DIY PVC overflow?

[Reef Pilot]

Originally Posted by trilinearmipmap

Just wondering with the airline to the pump to suck air to prevent losing the syphon, can the airline itself not become a syphon and cause a flood?

As soon as the flow stops as with a power outage the water level in the tank drops below the overflow immediately, so no more flow from the tank. And the airline syphon will then break, too.

And to be extra safe, you can put another open elbow (instead of the plug) pointed up at the end of the overflow that will then be slightly higher than the serrated overflow pipe, in case the overflow gets plugged with debris.