We have a large brick lined well near the beach in Mexico (not drinking water) and I have been pouring in a 1/2 gallon of bleach every month of so. Recently had to replace a one year old water heater due to tank leaking and was told bleach will eat them. My opinion is it was just a just a faulty tank or cheap brand.
Too much chlorine might have been a problem, especially the day you added the chlorine. The make chlorinators for well water, have you had your water tested?
Too much chlorine might have been a problem, especially the day you added the chlorine. The make chlorinators for well water, have you had your water tested?
Buy a cheap swimming pool type water test kit. See how much Free Chlorine is in your water 30 minutes after you add the bleach. If it's above 4ppm, it's way too much and you're eating the tank from the inside out.
Try adding ¼ cup every two days instead of the ½ Gal every month.