Need help placing my Check Valve on Return Pump x_x

[francis]

Hello everybody, today I was able to finally set up my diy pvc overflow. It is working okay but...I think I have a problem.

Now, I do not have a check valve on the PVC pipe because I thought after initially starting the siphon...I would never have to do it again if everything was working properly. My problem is that when I turn off the return pump to simulate a power outage, the return outlet begins siphoning water from the display tank back to my sump. Normally this would not be a problem because I have space for the excess water in my sump however, when I turn my pump back on the overflow pipes do not re-establish siphon like they should. Can somebody help me please? Thank you

[Sparky74]

I put air tubing inside the U tube for the overflow and connected it to the venturi intake on a powerhead. I'm not sure if this is the problem, but if you are getting flow back to the tank and the overflow won't siphon, it's probably air bound. The powerhead sucks the air out and allows it to re-establish siphon.

I'm sure there are other ways, but that worked for me with the materials I had at hand.

[David S]

All you need to do is drill 2 small holes in the return pump pvc pipe just below the normal operating water level,this will act as an air break and stop the syphon.But you should never loose the syphon in your overflow ,if you do then its made wrong.post a picture of it.

[francis]

Do you mean a hole below the normal level in the refugium, or in the display tank?

[David S]

2 holes just below normal operating water level in the display tank,I say 2 because just in case 1 gets blocked by for example a snail.these holes will also aggitate the waters surface as well when running.