Non Return Valve.

[steve01]

Hi All, I wonder if you can help me I have a Fluvall Roma 200 tank and I am running a Tetra-tec air pump for a air bubble curtain, now my problem is I dont think that the non return valve is working this is the second one I have put on the air line just above the top of the tank, my problem is the water is syphoning back down the line I had an airflow adjusting valve on which I took off because water was leaking from that so now I have got a clamp on my line which I have to completly close every night I have put the non return valve on the right way round so have any of you got any suggestion's for me please.

Thanks.

Steve.

 

[Axleuk]

Are you sure you have it on the right way around? The arrow pointing towards the aquarium? I know you said you have but to have 2 return valves not work is a bit of a mystery. Try a different make than the previous ones you have used and see how that goes.

 

[OldMan47]

A much more reliable answer than a check valve is to position the air pump higher than the waterline in the tank. No matter what happens after that, the pump will be safe from water and water will not siphon from the tank.