What To Do When Your Pond Water Turns Brown

Sooner or later almost every pond owner will encounter brown or green water in their pond, and for those experiencing it for the first time, it can be quite distressing. It is particularly prevalent in koi ponds, and to get rid of it, you must first understand the underlying cause.

Why Pond Water Turns Brown

Brown pond water is the result of a tannin buildup. Tannins are a type of molecule which is polyphenolic and derived from plants, especially those which break down. Various species of plants create tannin, which is the ingredient that gives Western tea its brown color. Tannin plays an important role in protecting plants from predators, and is also responsible for the management of plant growth. They provide color as well as astringency to certain brands of wine and even coffee. But while brown is a delightful color to have in these beverages, it is the last color most pond owners want in their water.

How To Get Rid Of It

You will first need to identify the source that is making the pond water turn brown. In most cases this will be a buildup of plant material, which you or someone you hire will have to remove. Sticks and leaves near the surface or by the edges of the pond also play a role in making the water turn brown, so they will need to be eliminated as well.

If the water is extremely dark colored, this means the source is most likely at the pond’s bottom, and you will have to remove debris like acorns, leaves and sticks by hand. There are no shortcuts when it comes to getting rid of tannins, and for larger ponds it will be hard work. Once you’ve removed the tannins you will next need to focus on the sludge.

Sludge Is A Major Cause Of Pond Water Turning Brown

While a small amount of sludge isn’t bad and should be expected, too much of it can turn the water dark. There are a few ways to deal with it, such as ensuring the pond always has a healthy amount of aerobic bacteria, whether within the water or a filtration unit. The algae’s slime layer should always be correctly maintained, and many pond owners use aeration to keep oxygen flow within the pond. If sludge isn’t kept under control, it will create a seal which will prevent enough oxygen from circulating.

Once you’ve removed all the debris and excess plant material from the pond, the next logical step is a water change. Some pond owners perform a partial change, and the purpose of either a full or partial change is to allow algae and healthy bacteria to dissolve the tannins as time passes. If you want to get rid of the brown water quickly, the fastest route is to place activated carbon within the pond. It will attach itself to the tannins and other unwanted materials and remove them from the water.