| 摘要 |
<p>The vulcan stone is for use as a filter in an aquarium, its base and top being cut off flat and detachable from the central part. The latter has drillings filled with filtering material, one of them being connected to a suction pipe and an air hose passing through the top to the upper edge of the aquarium, for the circulation of the water to be filtered by means of a pump. At the lower end of the central part there can be a water inlet port with strainer while there can be two drillings separated by a partition with a recess in its top, through which water can flow from one drilling to the other.</p> |
