https://www.knowfengshui.com/the-feng-shui-salt-water-cure/
The role of the salt water cure is to neutralize a specific quality of energy brought by specific negative stars, or feng shui energies. To achieve this effect, the salt water cure is usually applied in combination with several Metal element feng shui cures because the energies of these challenging stars are considerably weakened or even destroyed by the power of the Metal element. This happens because these negative feng shui stars — star 2, star 3, and star 5 — belong to a feng shui element that is weaker than the Metal element (star 2 and star 5 are of the Earth element, while star 3 is of the Wood element)
Most popular feng shui Metal element cures used in addition to the salt water cure are the 6 hollow metal rod wind chime, a metal Wu Lou (Chinese gourd), as well as bells and bowls made of metal. The salt water cure itself has a strong Metal element in it as represented by the six Chinese coins. The use of number six in the six hollow rods wind chime, as well as the six Chinese coins in the salt water cure, strengthens the power of the Metal element because in feng shui, six is considered to be a number with a strong Metal element essence.