I have a 1" barb male thread fitting that is screwed in to a PVC tee.
It was new work and I used teflon tape. Upon water testing, it was
barely leaking, maybe a cup a day. Tried tightening it more, didn't
make a difference. Took it apart, re-wrapped it with teflon tape
really well and now it leaks much worse, maybe quart+ a day.

This is on an irrigation well, so I wish I had never even noticed it
as the tiny initial leak wouldn't have amounted to anything. But now
that I'm down this path, what next. It would be very difficult to
change the T. Since it's an irrigation application, I'm thinking of
using Permatex as a next step. Only concern would be if Permatex
could destroy the PVC over time? Any other ideas? TIA