Green & Blue Set for making Strong Kangen Water and removing sediment. 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. Blue Filter: Used for removing sediment, which pre-treats hardness minerals to help prevent scaling on the unit’s plates for upto 1500 gallons.