John Guest Bulkhead leaking

[MrWolf]

Hi,

I purchased a John Guest 1/4 bulkhead fitting for my 5.5 gallon Ro/Di reserve aquarium. I want to use it a gravity auto top-off.
at first, it leaks between the tubing and the fitting so I purchased another one, I tough I just got a bad one.
same thing happens with the second one.
As a test, I connect a tubing on the inside of the tank long enough for the tubing to get out of the tank and filled the tank. (no water should be able to pass through the fitting) but it leaks again.
What is the purpose of a bulkhead if it's not sealed?
Anyone have an idea on how to seal it?

Thanks

 

[dbl]

I've never had one leak. You need to make sure you're pushing the tube all the way in to the fitting. You might think it's in because it feels like the tube "stopped". Try pushing the tube in a little further and you might find it will go in just a little more. I'm not saying this is your issue, but it's worth taking a look.

 

[MrWolf]

I think my problem is the same as this one explained here: https://confluence.cornell.edu/display/AGUACLARA/Leaking+Bulkhead+Fittings
but I don't like the solution.

 

[MrWolf]

if I use the bulkhead as union, it doesn't leak.
it's only when water goes "on" the bulkhead that it leaks from between the tubing and the bulkhead.

 

[JoshH]

so it's not the tubing that leaks it's the seal of the bulkhead itself? clearly the tubing is sealing properly if when you use it as a union you have no problems. somehow it's not properly sealing to the ato container itself. Have you tried a rubber ring around it on the inside to provide a better seal? I'm interested to see what comes of this as I was thinking of doing the same thing but don't want to run into issues like you have

 

[MrWolf]

I found the problem. The bulkhead is not made like it should.
I cut the first one I had and as you can see, the O-ring and tubing are in an inner union but their is nothing to seal the inner union with the outer bulkhead.
this shouldn't be called a bulkhead at all...