Return Valve

14 Jul 2007
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What can I do to prevent the water to flood the sump in case of a power failure?

I had a non-return valve in, but that slow down the waterflow.

Please help
hey dude try drilling a hole in the return pipe just under or level to the surface of the water assuming it enters quite deep into the tank. as the power switches off a certain amount of air will enter as it syphon's thus causing am air block and break the syphon. when the power is restored the air will be pushed out and all will be normal...

testing that this works is very important or else you will have your whole tank emptied onto your lounge floor....

good luck
It will work, as soon as the air is sucked up it will break the syphon, dont trust the non return valves as they do often stick in the open position.
what size hole are we looking at drilling les?in my case its a 25mm piping
5mm hole should do fine i went 4mm and it battled.. be sure to clean the burs out of the hole!!!!
No.... the hole is drilled in the return pipe in the display itself just below the water level.
My sump is quite small, it will flood easily. I think I will drill it just above water level.
Chelmon, do you have the option of raisig your return pipe so that it sits on the water surface in your display tank? If so this will work as a quiet return and will also not siphon if teh power goes off.
no. where the return pipe enters the tank..... and perhaps drill a little closer if not level with the surface....
My sump is quite small, it will flood easily. I think I will drill it just above water level.
Bear in mind, if you do that you will have water squirting out of the little hole and possibly make splashes which will cause salt creep.
if it slpashes just stick a bit of airtubing in the hole and have it run into your overflow.
this is what i did. dont remember why i drilled two holes:001_huh:


This is where the Hole should be mekaeel, also use one of the air restrictors that come with the Resun powerheads, once you have drilled the hole, you can glue it in and point the flow towards the water, thus having a "syphon break" a centimeter or so above the water
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