Siphon break

[cdalmost]

Hi all, the return pipe from my sump to my tank is 3/4" PVC. How big of a hole should I drill just below the water line to guarantee to break the siphon when the pump is switched off? I could experiment, but one of you guys probably knows the right size off the top of his or her head.

Thanks,
Chris

 

[bnmir]

3/16 or 1/4" imo

 

[raynist]

I did 1/4, and do more than one. If a snail is covering one it will not work.

 

[Spyder_78]

I drilled three in mine, I think they are 3/16".

 

[iamwrasseman]

3/16" is all you need and it could be smaller but you have to check it so it doesn't get clogged from time to time .