Our Tannin Water Filters are self-backwashing systems that automatically remove the tannins within the filter bed and washes them down the drain. This is accomplished with the microprocessor control valve that is mounted on top of the Crystal Quest® Tannin Water Filters. This valve is controlled by a meter that calculates the amount of water being used. Once the meter reaches "X" amount of gallons, it then initiates the backwash cycle that cleans the bed of filtration media and resets it for the next period of filtration. These systems connect to the main line of your home and filters all of the incoming water to it. It requires a nearby power outlet for the control valve. Low maintenance. Just add sodium or potassium pellets to the brine tank.