Some Hanafi authorities expressed the large-pond condition as a surface-area measure: about ten cubits in length and ten in width, using the specified cubit standard.
This is a juristic measurement intended to express sufficient distance between sides. The pond must also have enough depth that ordinary drawing of water does not expose the bed.
The movement and area tests are different methods for addressing the same question of sufficient separation.
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Impurity in Stagnant and Running Water, Large Ponds, and Aquatic Creatures
Some Hanafi authorities expressed the large-pond condition as a surface-area measure: about ten cubits in length and ten in width, using the specified cubit standard.
This is a juristic measurement intended to express sufficient distance between sides. The pond must also have enough depth that ordinary drawing of water does not expose the bed.
The movement and area tests are different methods for addressing the same question of sufficient separation.