Flowersmakemesmile,
From what you are describing it might be that there is a small area at the point where the coupling was placed that needs to either be re packed with mix and painted over, then resealed, or maybe an easier way to check would be to put a little bit or clear silicone marine caulking in the area to see if that takes care of the leak.
Dena

Thanks, again, Dena for all of your suggestions. I have been given elastomeric plastizer from Menards, an epoxy covering from Michaels (which is new to our area and totally blew my mind!!) but that was pretty expensive. I did what you suggested before (ie to build up that area where the stem is with a thicker layer) on fresh, unpainted concrete and that birdbath (still unpainted) is holding water. It is the ones I already painted and sealed that are giving me the hassle.

Does anybody else out there use anything different?

Remenber to put on the seatbelt.And,after you've taken it for a long drive,does iot sleep better?
Cheers