The "D-1" is a high-speed filter designed to filter aquarium water to an extremely pure state. It is designed to operate as a full-time filter. However, it may be used in cooperation with other filters such as under-gravel filters and in conjunction with other outside filters. It is wholly compatible with all known filters and may be used to aid these filters in keeping a healthy, well-balanced aquarium. Used properly, your Diatom filter will eliminate the need to tear down or disassemble your aquarium in order to clean it.