Calif Bill wrote:

It will eat the copper. If high enough concentration.

The chemistry of the reaction between Cu and HCl are well
documented and easily researched on the web. There is no
reaction.

As one who regularly uses highly concentrated HCl to remove
seawater deposits and biological growth including barnacle
cement and "husks" from shipboard machinery I can assure you
it will not "eat" copper or most copper alloys normally used
in marine applications.

HCL will react with oxides of Cu and nearly all of the
components and structure of a home swimming pool as
illustrated by your friends experience.


Rick