seems to be coming from the T connection from dishwasher
Determine if the tee connection is a self tapping connector. These often leak. The best solution is to install an actual tee in the line. Since it is likely that the pipe is in an open area, you could use a compression tee.
The entire joint will have to be replaced and sweated in. FYI, it's almost always the hot lines that leak because they corrode faster than cold copper lines.
flying dragon is quite correct in his answers. In addition Mg+2 is a co-factor in over 50 enzymatic reactions in the body and is involved in all reactions involving phosphate transfer( hydrolysis of ATP, pyrophosphatase, etc )
