I'm just installing a water softener which has a plastic, which I believe is nylon, valve. I ran 3/4 copper lines down to it on which I installed a 3/4 x 1" threaded female copper fittings. I put teflon tape on the male plastic fittings and installed. When I turned the water back on, I noticed some drips coming out of the connection. I tightened the fittings some, careful not to over tighten and break the plastic fittings. Checked again and still had some leakage so I went to pipe sealant and thought I had it licked, but I still have a very small amount of leakage. I don't want to tighten more as I'm afraid I might break the plastic fittings. Suggestions?