The CA2Tannin Reduction Filter System is installed following a Twin or Triple cartridge Whole House Water Filtration System which first removes sediment particles. The CA2 is an automatic filtration system which contains silver carbon media to absorb tannin from the rainwater supply. Silver is used to inhibit bacteria growth in the media. The system automatically back-washes itself on a weekly basis to remove impurities and ensure the carbon media is performing at it’s best to reduce tannin from the rainwater supply.