Green & Purple Set for producing Strong Kangen Water and general filtration with chlorine removal. Green Filter: This ion is an ion exchange filter, which softens your water, softening the hardness present in the water. Reducing the dissolved calcium and magnesium, some manganese and ferrous iron. This filter is best used when making strong Kangen/strong Acidic water. Purple Filter: This is a triple sediment, taste and odor controlling, chlorine reduction filter, which removes dirt from your water while controlling lime and scale deposits on your valuable equipment. Better taste, better water, better for you.