Rcpilot
Reef enthusiast
Thats it.
My return line comes up over the back of the tank and runs under water inside the tank. The tank drains down until the water is beneath the teeth on the overflow. But it won't stop there. It will continue to flow backwards now through the return lines. It would siphon back into the sump until the end of it sucked air and broke the siphon.
The holes is placed so that as soon as the overflow teeth are out of the water (no more water flowing through the overflow) the hole becomes exposed and begins to suck air. It sucks enough air to break the siphon and stop the tank from siphoning backwards through the return line.
My return line comes up over the back of the tank and runs under water inside the tank. The tank drains down until the water is beneath the teeth on the overflow. But it won't stop there. It will continue to flow backwards now through the return lines. It would siphon back into the sump until the end of it sucked air and broke the siphon.
The holes is placed so that as soon as the overflow teeth are out of the water (no more water flowing through the overflow) the hole becomes exposed and begins to suck air. It sucks enough air to break the siphon and stop the tank from siphoning backwards through the return line.
