take a sirclip you use on hoes pipes then unscrew till open then take a piece rubber or a small piece of the hoes pipe cut it to fit over the hole you will need to open the pipe up and rejoin the sirclip round the pipe and dont over tighten, or empty the system clean area with steel wool,flux and solder over the hole eric
If the pipe has pressurized water in it, you should have that section replaced.
Replace the pipes. There is no other solution because the pipes are worn out. If you could find a fix, another leak will soon appear elsewhere.
I prefer to replace using CPVC piping. Cheaper, easier to work with, and is not subject to erosion from acidic water like yours.
More Information please
try flex tape . According to the commercial it is suppose to fix it instantly
take a sirclip you use on hoes pipes then unscrew till open then take a piece rubber or a small piece of the hoes pipe cut it to fit over the hole you will need to open the pipe up and rejoin the sirclip round the pipe and dont over tighten, or empty the system clean area with steel wool,flux and solder over the hole eric