Do I have the right tank bulkhead connector?

[kungfuman]

Hi, after being out of fishkeeping for many years, I am about to set up a new tank and my first time with a sump.

i recently bought a new tank with bottom holes drilled for piping to a sump.

i spoke to an aquarium supplier for the plumbing and they have sold me the attached photo tank connector.

they advised me to install the threaded end inside and the gasket being outside.
Firstly this goes against what I’ve read about fitting the gasket as it should be inside so the outside nut doesn’t distort it when tightening.
secondly I don’t understand this connector seals as i'm thinking the water will get into the threads and bypass the joint?

the only way i can think of to make this robust is to have the stem end on the inside and the nut fully tightened against it so sealing off the threads (maybe even using sealant around the threads?) and also installing the gasket on the inside.

have i got this right?

 

[ReApEr666]

Havent seen a bulkhead with removable inside nut... shouldnt change the principle tho. Gasket always goes on the inside to make the seal. Tighten by hand. No silicone is needed as others may suggest. After u tighten it go back later and hand tighten a bit again. You can usually get another half turn or more after the gasket compresses a bit.

 

[kungfuman]

Havent seen a bulkhead with removable inside nut... shouldnt change the principle tho. Gasket always goes on the inside to make the seal. Tighten by hand. No silicone is needed as others may suggest. After u tighten it go back later and hand tighten a bit again. You can usually get another half turn or more after the gasket compresses a bit.

thats what i dont understand though, wouldn't a removable nut on the inside be a leak path through the threads?

 

[DThompson]

thats what i dont understand though, wouldn't a removable nut on the inside be a leak path through the threads?

Yes, you will still have a leak through the treads. The gasket around the flange of the nut wont help with this leak. I haven't seen a bulkhead like this before.

 

[ReApEr666]

thats what i dont understand though, wouldn't a removable nut on the inside be a leak path through the threads?

only 1 way to find out lol...worst case scenario use reg. pvc primer and glue and just make that 1 nut permenant to not worry. or chaulk it up to a learning experience and order a diff/reg. style bulkhead. If that was the only part I had to work with id give it a shot see what happens...easy enough to add some pvc glue if there is a problem. all part of the game IMO... trial and error.

 

[kungfuman]

only 1 way to find out lol...worst case scenario use reg. pvc primer and glue and just make that 1 nut permenant to not worry. or chaulk it up to a learning experience and order a diff/reg. style bulkhead. If that was the only part I had to work with id give it a shot see what happens...easy enough to add some pvc glue if there is a problem. all part of the game IMO... trial and error.

ok i see what you mean, essentially just glue the nut threads onto the pipe thread section so becomes one part.

on another note, i only bought uni-100 xt solvent cement which i thought was all i needed i see you also mention a primer, is that essential?

 

[esoxlucius]

ok i see what you mean, essentially just glue the nut threads onto the pipe thread section so becomes one part.

on another note, i only bought uni-100 xt solvent cement which i thought was all i needed i see you also mention a primer, is that essential?

Using glue or silicon is fine, if not a little on the permanent side. I always put loads of PTFE plumbers sealant on my threads. It comes in like a flexible plastic tape form but without the adhesive. Wind it round the threads several times and screw in.

 

[DN328]

How many of those bulkheads did you buy? If inches matter the piping will go lower since it's a longer bulkhead.

Don't forget ABS/PVC transition cement.