How often should I change my Koi pond water?

How often should I change my Koi pond water?

Many of our customers may be seeking clarity on how often they should change their pond water. While we understand that there is a myth that states there is no need to change the water frequently as long as proper maintenance is done, we strongly advise our clients not to follow suit. Over time, pond water accumulates organics and toxic gases, which creates the need to keep changing the water. Failing to change the water may result in the excessive accumulation of these toxic substances that may be harmful to any organism living in the pond.

             The number of times you change your water depends on the size of the pond. Any pond with less than 5,000 gallons can be considered small, and one needs to replace 5-10% of the water on a weekly basis for it to remain healthy. Changing all the water at once may result in more harm than good, which is why the water is changed gradually. Larger ponds of more than 5,000 gallons, also require a 5% change, but it needs to be a continuous process that utilizes the overflow pipe. In this case, we have water trickling in and out, guaranteeing a smooth flow of clean water in the pond. 

To get rid of chemicals, you can use a water purifier and a fine spray on your hose nozzle. The overflow pipe method is the best while replacing pod water. It allows gradual trickle of water in and out of the pond as opposed to other ways that many deliver the correct amount of water intended. You can test this by following the steps below;

  1. Place a bucket below the overflow pipe.
  2. Measure the liters collected to help you estimate what 5% of the water in the pond would look like
  3. You get to see the flow rate which allows you to easily make an estimate on the duration it would take to have a 5% water change
  4. Based on the flow rate, you would get a rough estimate on the time required to change your pond water.

Once you establish the flow rate using a bucket, it is easier to make weekly changes based on timing. In a pond with 5,000 gallons, to achieve a 5% water change, we need to run a hose on half pressure through a water purifier for 20 minutes. We utilize a 5% water change each week for both large and small ponds. In an instance where one lacks an overflow pipe, one can utilize a pump//bucket and replace it with a fine spray.

What to do

  • Use an overflow pipe.
  • Utilize a fine spray with a hose/ water purifier
  • Change 5-10% of the water quantity per week.
  • Use a bucket to measure, to make the process easier.

What to avoid

  • Changing more than 10% of the amount of water in a pond at one time (ask an expert before trying this)
  • Leaving the pump running more than the intended duration

Note that during winter, a water change may not be necessary since fish are inactive. Water change is mainly necessary during March-October.

We hope that has cleared up any questions regarding how often to change water in your Koi pond.  Feel free to comment below and ask any other questions you may have!