There are many common misconceptions about Bleach. The greatest misconception is that all bleach is created equal. Cheap, no-name or bargain brand bleach is mostly water and will not brighten your whites. My favorite brand is Clorox or Clorox concentrate.
Use the manufacturer's recommended quantity. Using more bleach than is recommended is very hard on the fabric. Putting bleach directly on cotton fabric will “eat it,” so be sure to use the bleach dispenser on your machine.
Chlorine bleach must be used with hot water in order to “activate” the bleach. The water temperature has to get to 150 degrees or it won’t be effective. If the water isn’t hot enough, the bleach causes the fabric to yellow.
White cotton has naturally a grayish tint. The bleach helps keep the cotton fibers bright. Without chlorine bleach, white fabric will gray over time.