Filter, particularly for pond water

摘要

A filter suitable for a pond comprises a container (2) housing a mass of filter material (3). A tray (8) is located at the upper end of the container and substantially closes the upper end. Raw water is delivered to the tray by suitable means, e.g. a pump via a riser (7). Apertures (12) are provided in the tray at a predetermined distance above the bottom surface thereof such that when the water level within the tray rises above the level of the apertures the water will flow from the tray into the filter material (3) thereby maintaining a constant water level in the tray. A layer of growing medium (17) is located within the tray supported on a barrier (16) located at a level above that of the apertures whereby plants may be planted in the growing medium and their roots may extend into the portion of the tray below the level of the apertures to remove nutrients and/or other minerals from the water flowing through the tray.