An "as-needed" chemical. Metal Sequestering Agents can either be liquid or granular. Metal Sequestering Agents are used to treat odd tints to the color of the pool water, stains, or the formation of scale. These odd tints, stains, and scale can either result from the minerals that are present in the tap water that is used to fill the pool (such as copper, iron, manganese, magnesium, or calcium) or result from poor water chemistry. If an odd tint, any stains, or the formation of scale are present, the condition can easily be rectified by re-attaining and maintaining proper water chemistry and by using a Metal Sequestering Agent, which will rid the water of these excess minerals. Read the instructions on the label to determine the amount to add, how it should be added (either diluted in water or poured/broadcast straight from the bottle/container), and other precautions. Issues such as "minerals," "the presence of metals," "odd tints," "stains," and "scale" cause much confusion.