Neptune's years are 164.8 Earth years. Its days are 16 hours and 6.7 minutes long. Although Neptune's days are shorter than our days, its years are still longer than ours.
Most colorants will last in your pond approximately 30 days. You may have to add more pond dye before 30 days if you have execissive rainfall, run-off, a heavy out flow, or evaporation. If your colorant is fading you will visually be able to tell and should add more dye to the water.
How long does demi permanent hair color last? A: Demi permanent hair color can last up to 6 weeks and typically fades after 20 to 28 hair shampoo washes. As a hair-coloring agent, demi permanent formulas are used to enhance natural hair color, to darken the natural hair shade and to refresh previously colored hair.