# Correct Fitting of Non Return Valve



## super7star

Hi there

I wonder if someone could help. I am setting up a fish tank for the first time, it has a pump and a non return check valve, this one:

http://www.swallowaquatics.co.uk/179/pr ... rline.aspx

I'm not sure which way around the valve should be fitted (no instruction :frown should the black end connect to the airline coming from out of the water or is it the other way around?

Sorry if this is a dumb question, I'm a novice  !

Thank you


----------



## hawksport

Put it in your mouth and try to blow though it. You will only be able to blow through one way, the end that is in your mouth when you can is the end that should go to the air pump


----------



## hawksport

I would also still have a loop of airline above the top of the tank, check valves can fail and lead to an empty tank


----------

