This is an AEROBIC method for making compost tea or fertilizer tea or manure tea. It's a closed loop system, As the water drips down through the bucket of rotting plant material, there is massive oxygen contact along the surfaces of the material, so it rots fast and the nutrients that rotting produces get carried away in the leachate to the growing plants. This method provides nutrients and carbohydrates to the plant roots as the compost rots in the bucket, the plants clean the water at each pass . Because the compost tea is being used as fast as it is being made, it never becomes really strong. The airlifting of water is Aerobic, water dripping through the compost is aerobic too and this all helps maintain high quality compost tea.