Air Tank Valve Leaking

[Mobius V]

Dont know if this is what thread this should be in but mods move if needed, I had some of my tanks hydro tested and they came back to me with the valves not installed back in, two out of the three I put in and had no leaks but my last tank is a 48ci 3k steel pmi pure energy tank and I can not get it to seal, I have tried several different orings on the valve and thread tape. Any suggestions will be appreciated thanks!

[athomas]

Make sure the threads are clean and unblemished. Make sure the oring is the proper size and isn't punctured or damaged in any way. If the surfaces are smooth and the oring is good, it has to seal.