On 1/18/18 9:15 AM, trader_4 wrote:
That's at the age where typically you have problems with steel pipe
failing. It actually corrodes and fails from the inside out, kind
of like artery blockage in people. That could be contributing to
the clog.

I had some old "white" (zamac?) metal piping replaced
several years' back. The inside was all "honeycombed" with
builup that was hard as a rock (calcium in the water?)...