How to Change Water in a Koi Pond

Do you want to ensure your koi fish are happy and healthy? Learning how to change the water in a koi pond is one of the essentials for keeping these attractive little fish. Over time, the water in the pond evaporates, leaving behind dirt and gunk concentrates.

How to Change Water in a Koi Pond

A pond filter does an excellent job at removing impurities. However, this alone isn't effective enough. Changing the water eventually helps keep a fresher and cleaner environment, allowing the fish to thrive better. Additionally, frequent water changes in the pond help to replenish the environment with adequate mineral supply. Here's how to change the water in a pond with fish.

How Often Should You Do a Water Change on Your Koi Pond?

To successfully maintain a healthy pond environment, knowing the frequency of changing its water is crucial. To determine the water changing frequency, you have to consider several factors. These include  the size of the pond, the amount of fish you have, your filtration method, and quality,  to mention a few.

Remember, the water in the pond also affects the overall environment, including food supply.

So, while keeping these factors in mind, you also have to conduct frequent water quality tests to know when to do the water changes. For example, if you notice high waste concentrations during your water quality tests, you may have to increase the frequency of your water changes.

As a general rule of thumb, you can use water volume changes to gauge change frequencies. However, this method doesn't take into consideration factors such as the pond or fish size. Typically, a 10% to 20% volume change will require the water to be changed every week.

As this rate increase by 10% increments, you should also increase the change frequency. So, a 20% to 30% rate will require water changes every two weeks, while a 30% to 40% change will require water changes every three weeks.

How Much Water Should I Change?

Similar to the frequency of water changes, there isn't a standard value for how much water you should change. Again, you have to consider  the pond size, fish and plant size, filtration system, and climate  to determine how much water to change.

How to Change Water in a Koi Pond

Generally, water changes don't constitute draining all the water. After all, a complete shift in the environment may shock the fish and pond ecosystem. Changing water has both positive and negative effects on your fish pond. When a significant amount of water is removed, you will also remove toxic organic wastes to keep the fish safe.

However, adding a fresh batch of water can also introduce inorganic substances such as chlorine and chloramines that may be toxic to your fish.

In this case, it is advised to change at least 10% of the koi pond water once every week. A water quality test is another helpful tool for determining how much water to change. For example, you may change 10% of the water weekly, but notice increased pollutants during your weekly quality tests. Due to the increase of pollutants, you may have to increase this rate to about 20% every week.

How Do I Do The Water Change?

Changing water from your koi pond is pretty easy. Depending on your pond design and system, you can find various methods for changing the water in it.

How to Get Old Water Out of Your Pond

The simplest and cost-effective way for doing so is to use a bucket. Scoop out the water using the bucket, making sure you don't pick up the fish too. Remember, you should drain a certain amount of water. Thus, as you scoop out the water using a bucket, record its volume to prevent taking out too much or too little water.

If a bucket doesn’t work out for you, you can use a vacuum, pump, or siphon hose. Some modern pond systems come with controlled overflow systems. Therefore, you can use this system to drain some of the water out of the pond. However, like any other method, you have to ensure you take note of the water volume being drained to prevent overdoing it

How to Add New Water to Your Pond

Adding new water to a koi pond is pretty simple too. However, you shouldn't just add tap water.  Due to its chlorine and chloramines content, tap water is toxic to fish . Chlorine kills living cells and can easily target koi fish-sensitive gills and skin that cover their body.

So, dissolved in your koi fish pond water, it targets their respiratory system and may suffocate them. On the other hand, chloramines combine a potent blend of chlorine and ammonia. Chloramines don't quickly evaporate and can remain active in the water for quite some time.

So, before you add tap water to the pond, you have to dechlorinate it first.

Removing chlorine from tap water features a simple process as well. All you have to do is fill up a large plastic barrel with the water you intend to add to the pond a day before you do so. Next, let the barrel stand for about 24 hours, allowing chlorine to evaporate automatically.

This method works perfectly for removing chlorine from water. However, if your tap water contains chloramines, this method is pretty much ineffective. So, you have to invest in more specialized treatment for your tap water to remove chloramines before adding it to your fish pond thoroughly.

If tap water doesn't work out for you, the next best option is rainwater. Rainwater is an excellent alternative as it doesn't contain chlorine.

But, you still have to conduct a water quality test to ensure it doesn't contain any impurities or contaminants that may be harmful to your fish.

Using rainwater for your fish pond works great if you have a rainwater harvesting system.

How to Clear Up Green Pond Water

Irregular water changing habits causes water evaporation and build-up of gunk and residue concentrates. Ultimately, this results in the pond water turning green. The good news is that you can still fix this problem. Here’s how you do it.

How to Change Water in a Koi Pond

Step 1: Reinforce the Filtration System

Green pond water is caused by increased algae production. One of the first steps to tackling this problem is to invest in a more comprehensive filtration system.  A clean 3 stage filter does an excellent job at tackling this problem,  particularly the mechanical stage. The mechanical filtration stage works by removing waste that discolors water and adds toxic substances to it. On the other hand, chemical filtration removes discolorations, toxins, and odors from the water, while biological filtration removes compounds such as ammonia and nitrates, which algae primarily feed on.

Step 2: Add Shade

You should avoid locating your pond under direct sunlight. If you have already built one where there is direct sunlight, create some shade. Organisms such as algae depend on sunlight to grow and thrive as they feed through photosynthesis. Keeping your pond away from the sun helps to cut down its primary component for fueling photosynthesis.

Step 3: Invest in a Supply of Algae Eaters

Add natural algae eaters to your pond. Koi fish alone feed on algae. However, with the increased amount of algae in the pond, the koi fish population alone may not be enough. You can always supplement the koi fish with additional animals or fish they live harmoniously with to help with the task.

Step 4: Dye the Water

Honestly, the deep green pond watercolor caused by algae can be pretty unpleasant to look at. So, to mask this color, you can always invest in pond dye. You can opt for a regular green pond color, blue or purple.

Pond dyes don’t only assist in giving the pond a pleasant color. They also prevent sunlight from penetrating deep into the pond. Blocking the sunlight reduces the rate of photosynthesis, which, in turn, reduces the food supply to algae and stunts its growth.

Step 5: Add Plants

Unbelievable as it may sound, adding more plants to your pond does help to clear up the green watercolor.

Adding more plants underwater results in by-products such as ammonia and nitrates being filtered out.

This, in turn, significantly cuts down the food supply for green algae. You can also add plants that float on water. These plants help block out sunlight from penetrating deep into the water, blocking fuel for algae to photosynthesize.

Step 6: Regularly Change the Water

While you observe the steps above, regularly changing water in your koi pond is an essential practice too. Changing the water helps to balance out the environment in the pond. It also complements the steps above by removing compounds that discolor the water, leaving the fish to stay healthier.

Additional tips for clearing up a green pond include aerating your pond and supplementing it with beneficial bacteria that aren’t harmful to the fish.

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