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 Hair Dye Allergy Last? Allergic reaction to hair dyes can appear from a few minutes to up to a week to ten days after the initial exposure to the hair dye. Some individuals' reactions get better in a few days, whereas some have symptoms for a longer period of time.