Depending on geographical location, water quality can be quite variable. Fluorination, pH, or other minerals present can impact not only how the dyes are picked up by the tissue, but also the life of the dyes. Because hematoxylin, for example, is slightly acidic, a basic pH tap water can raise the pH of the hematoxylin, making it less effective. If the tap water quality is poor or variable, the use of deionized (DI) water is a great option. Just remember to make sure the DI water pressure is sufficient for your automated platform stainer if it is directly connected to the instrument.
