I have used 2 paRT EPOXY TO STOP MINOR LEAKS.

iTS REALLY BETTER TO TAKE IT APART AND START OVER the corrosion may be
attacking the tanks connection area.

Dieelictric unions are a good idea.

If the lkeaks at the tanks connection and you dont fix it one day soon
you will need another new tank Have that one pro installed its
cheaper than buying another new tank