I'm trying to install a undersink water filter system. I've removed the cold kitchen tap connector hose and replaced it with a FEMALE TEE 15MM X 15MM X ½ but the depth of the female branch is deeper than the male so it's reaching the end before tightening properly. I've tried it with 2 rounds PTFE tape but it's causing a slow leak. https://photos.app.goo.gl/gnGeAYVrteBeDtUG8 I have a feeling the male and female connectors are different standards. Can anyone confirm and suggest what I can do? Use more tspe? I can't seem to find a female tee all with 15mm.