The Importance of Pond Dye
Using dye in your Natural Swimming Pool/Pond is important because it helps protect the water from harsh direct sunlight. The sunlight doesn't harm the water itself, but is a large factor in algae growth.
There are a few key times in the life of your NSP when dye is especially helpful. The first being when your NSP is first built. When you've filled the NSP and your pump system is going you need to introduce the dye to protect the water for the first few weeks when the biological filter is establishing itself. The beneficial bacteria needs time to grow into all the nooks and crannies to prevent an algae bloom.
The second key time for dye is when you are most likely to experience an algae bloom in your NSP, which is early spring, and throughout the hot months of summer. Spring is the beautiful time when everything begins to grow back in, sadly this does include algae, which will be one of the first and easiest things to grow in your NSP. The dye helps prevent that spring sunshine from creating an algae party in your pool.
The image above shows the ideal amount of dye. Dark enough to protect against full sunlight, yet not so much that you lose water clarity and the joy of seeing your fish swimming around.