In traditional Feng Shui, placement of the 5-elements have the strongest effect in changing or adjusting the energy of a home, so the water element would be the first choice in placing a remedy where water may be needed. Color is the second choice when it is impractical to place an element-- because color has a subtler effect. Color is (light energy) and the blue light wave (light or pigment) has a very similar effect on the human organism as actual water. In Feng Shui the color blue and black are traditionally equated with water energy.
