Koi ponds that outdoors tend to have tea-colored or brown water sooner or later. Often, the water of your pond will be clear (not cloudy, but reddish, brown, or orange) with a distinct dark tinge to it. To solve this pond problem, you must first understand and address the causes of the issue.

Tea-Colored Water: What is it?

Try grabbing a clear glass jar, scooping out some water, and looking at it if your pond seems a little browner than usual. Is it brownish in color? In that case, your water is tea-colored or Brown Water. Do not let discouragement hinder you! There is no cure for this condition, but it is relatively easy to manage. A small investment will be enough on your part, as well as some effort from you. Having a clear pond brings joy to friends and family members when you share it, and once you make it, it will be part of the regular maintenance of owning a pond. 

It is most likely scum that has accumulated on the rocks and other features of the bottom of the tray. If the water in the tray is clear, then you will see brown from the scum. The problem can be solved the same way you would treat tea-colored water. Eventually, you will end up with tea-colored water if you ignore the problem long enough! In any case, read on!


Two kinds of treatments are available for treating this condition, as well as two types of causes. You have sediment in your water jar if you notice brown particulates on the bottom. Sediment is a physical material such as dirt, debris, crumbled organic matter, or waste from pets such as fish or birds. A pond’s sediment can collect at the bottom, but it can also float in the water for a long time until it becomes dirty brown. Filters can clog with sediment once they are full of sediment. 

There are certain chemicals called tannins that can cause brown water as well. When organic material breaks down, it produces tannins, which are polyphenolic molecules. Your pond almost certainly contains tannins if your jar’s water remains brown the next morning. Leaf tannins are responsible for the browning of fallen leaves. Your pond’s water will eventually turn brown as decayed organic material decays, much like a giant teabag. 

In tea-colored water, tannins have accumulated because of the buildup of minerals. Polyphenolic compounds known as tannins have the ability to… Isn’t that right? Those facts aren’t important. Anthraquinones are chemical compounds produced by plants when they break down. Tannins are found in a wide variety of plants, including oak trees (tannin is derived from an old German word for oak). The tannins in tea are also responsible for their brown color and bitter taste. In addition to adding astringency to wine, they give the coffee a slightly darker color. Leather is tanned using tannin (the source of the word “tanning”). They make water ugly, but they’re helpful and desirable molecules in many things.


In order to remove the tea color from your pond’s water, you have to remove the source that makes it there and take it out of the water itself.

It’s generally not difficult to take the first step, even though it isn’t always simple. Excess plant material needs to be removed from the water. You can skim away the leaves and sticks that are on the surface and around the edges of the water. It is likely that your pond’s bottom contains tannin-producing debris if there are enough tannins in your pond for real problems. The bottom of your pond should be cleaned manually of vegetation debris (leaves, sticks, and acorns). In your sludge layer, you should try to reduce the tannin content as much as possible, since this is where most of the debris will ultimately settle. Check out this more detailed overview of pond sludge. It really is impossible to remove tannins from their source by taking shortcuts. Regardless of how you treat the water, as long as the orange source is present, your water will always come out orange.

Treatment for Tea-colored or Brown Water

It is possible that your water contains sediment or tannins. You can get back your clean pond either way with specific remedies. By following these steps and performing regular maintenance, you should be able to resolve this problem.

Make sure your pond is clean

Tanning and sediment can be caused by decaying organic material. Using a skimmer net or similar tool, you should be able to easily remove twigs, leaves, seeds (acorns are an example), and any other debris from your pond. Scum and another sediment will need to be searched for on rocks and on the bottom. Using a pond vacuum will be the best way to do this. 

Make sure your filter is working

It is possible that you need to replace your filter. You can generally remove most sediment with a good filter. Ensure that the filter is relatively clean and that the water is flowing properly through it, and your water will be filtered. 

Change your water source

As much as you can remove from your pond by following steps 1 and 2, adding some freshwater will directly affect the problem. In this case, you will likely need to use a water conditioner if you are using tap water. Softeners, also known as conditioners, remove heavy metals from water and neutralize certain compounds such as chlorine and ammonia. You may have marine life living in your pond or visiting it, so you may want to do this.

Adding beneficial bacteria

In addition to your water conditioner, there are other treatments you can use to facilitate the breakdown of organic compounds in a way that won’t stain the water. By eating decaying organic matter, certain bacteria will keep your water clean. Make sure to consult an expert in pond care before choosing bacteria and follow the instructions on how to use them.

Use activated carbon

You should add activated carbon to keep your pond free of tannin stains. The water must flow rapidly over the sealed charcoal bag as per the instructions. Using charcoal as a filter will help you remove tannins from your water (as well as other compounds). You should be able to see your water clearly soon after.


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