how to stop return water from siphoning??

[K9bones]

Hello, I been planning on adding a sump w/ hangover overflow for quite some time. Right now i have everything running smoothly, but when i tested the system when i unplug my return pump to check to see if i have the right water levels to stop from overflowing, i found out that my return line, which i used pvc, is now siphoning the water threw it into the sump causing it to overflow. How do i stop it from overflowing?? I was reading online and came across someones setup/build saying they used a u shaped tube which has a build in anti-siphoning on it. How do i add a anti-siphoning to my return line so it doesnt overflow??

Tank setup atm,
75g glass
20g tank as a sump
mag7 pump
cs90 overflow box

later this week im going to buy a bigger tank 29+ tank to make into a sump.

 

[CHOMPERS]

Drill a small hole in the return pipe just below the waters surface. It will allow air to enter when the pump is shut off, and it will break the syphon.

 

[Carpet Man]

Same issue here.

 

[vanimate]

Drill a small hole in the return pipe just below the waters surface. It will allow air to enter when the pump is shut off, and it will break the syphon.

Yup this will solve your problem

 

[ken 429]

check out this pic,water level is a little low but normally the hole is just below the surface.

 

[K9bones]

Just drilled the hole, it works like a charm. Thanks guys !!!

 

[JN31]

CHOMPERS IS RIGHT....JUST DRILL HOLE ON RETURN LINE JUST ABOVE TANK WATER LEVEL....HAD SAME PROBLEM AND WHEN THE POWER GOES OUT FORGET ABOUT IT




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