Answer: Dye can be used for a variety of different reasons, primarily for aesthetics; it just makes the pond look better, the color of the pond. However, if you’re an aquatic manager like us, you use dye to filter sunlight and prohibit photosynthesis from occurring in the bottom of the pond bed where your weeds are growing or where algae may be growing. So, it has a dual job: it makes the pond look better, and it helps us manage the pond better.