Pond Air 4 SystemPond air systems are quiet and energy efficient. Pond air systems are simple to use and maintain. All units come equipped with air line, check valves, and weighted air stones. Pond Air 4 comes with 4 stones, 25 ft. of airline, and 11 watts. Pond Air Aeration Kits circulate the water from the bottom of you water garden to the top, creating a hole in the ice during winter months. This hole in the ice allows harmful gases from organic decomposition to