Generally, if your machine has a bleach dispenser, it is a good idea to use it. On some models, the dispenser automatically delays the addition of bleach, which is our “for best results” addition method. Dispensers that do not delay addition, conveniently add the bleach in a method that avoids direct contact with the laundry load before water is added. If your dispenser delays addition, I would recommend using it, and the user’s guide for your washer should indicate how the dispenser works. The delay is beneficial at helping a good detergent work better for two main reasons:
That said, there is a potential problem with bleach dispensers: some designs limit the amount of bleach that can be added. This prevents consumers from adjusting the amount of bleach they use to accommodate an extra-large or heavily soiled load. In that case, it is better to skip the dispenser and add the appropriate amount of bleach directly with the detergent as the washer is filling, before the laundry load is added. You can also wash two smaller loads if you have an HE washer that “locks” during the cycle, making it difficult to safely add bleach without using the dispenser.