How to treat Tea-Colored pond water.  

Brown or Tea-colored water is a relatively common problem that we see in backyard koi ponds.  When this happens the pond water is actually typically clear however it has a dark brown color.  To solve the problem we first must understand what it is that causes the problem.  

 

Causes of Tea-colored water 

The tea-colored water in your pond is caused by a buildup of tannins in your pond water.  Tannins come from plants that are breaking down and are in fact what causes your tea to be brown.  Several different plants produce tannins, such as oak trees, birch trees, willow trees, pine trees, and more.  If you have tea-colored water and one of these trees is near your pond, it’s likely that debris such as leaves are falling in your pond water causing the dark color.  

 

Water Treatment 

Getting rid of your tea-colored water is a basic two-step process.  You need to find out what the tannin-producing source is.  If you have one of the tannin-producing plants listed above you may need to remove or relocate the plant if possible to prevent any more debris from that plant from falling into your pond.

The second step is removing any excess plant material from the tannin-producing plant from your pond.  This may only require you skimming floating debris from the top but for most, it’s likely you will need to also remove decaying debris from the bottom of your pond.  Although you can try to use a pond net to remove debris it will likely be more effective and efficient to drain your pond in order to get in and remove the excess debris (leaves, sticks, and acorns) by hand.

When it comes to tea-colored water there are not any short-cuts you need to remove as much of the tannin debris source as possible from your pond.    

Once you’ve dealt with the tannin debris, getting rid of the brown water will be much easier.  A partial or even full water change will help and adding beneficial bacteria will break down any leftover tannins over time. An even quicker way to get rid of leftover tannins is by adding activated carbon to your pond.  This will bind with any remaining tannins and remove them from your pond water.