Black Rings in Toilet or Shower

This is due to mold or mildew. Mold and mildew thrive in warm damp locations such as a toilet bowl or shower. Mold spores are found naturally in the air and will land on damp surfaces and multiply. Bathrooms without a window or fan are ideal places.

Treatment:

Open windows or turn on the fan for ventilation for at least an hour after a shower.

Install a toilet cake containing bleach that attaches to the toilet bowl. Avoid ones that are dropped into the tank, as the bleach will start to erode the plumbing on the toilet tank.

To immediately clean any stains, use bleach and a scrub brush or sponge. Add 3-5 tablespoons of bleach to the toilet tank and flush. While the tank refills, add another dose of bleach to the tank.