Why You Need a Filter System for Small Water Gardens and Koi Ponds

Koi ponds and water gardens are a joy to look at; they help bring a touch of serenity to a busy, fast-paced world. What’s more, caring for your small pond can be just as meditative as sitting by the water.

And one of the primary aspects of pond care is a filter system. 

If you’re considering building a small water garden or koi pond on your property, you may wonder if you actually need a filter system. After all, a natural pond doesn’t have a filter, pump, or aeration system, and the fish and plants survive without any issues.

However, the truth is that constructed ponds differ considerably from natural ones—and the requirements differ, too. So, today, we’re explaining why you need a filter system for your koi pond or water garden.

How Filtration Works

Before we dive into the purpose of filtering in koi ponds and water gardens, it’s worth noting that there are three “stages” of pond filtration. The three types of filtration are as follows:

  • Mechanical filtration – A mechanical filter handles large, physical materials, including plant debris and waste from fish or other nearby animals. 

  • Biological filtration – A biological filter removes the harmful ammonia and nitrates that can build up in ponds over time, turning them into less harmful nitrates. Biological filters also house beneficial bacteria that make ponds habitable; as water flows through the colonies of good bacteria, it enters the pond. 

  • Chemical filtration – Chemical filters (often powered by activated carbon or zeolite) remove toxins from the water.

Pumps and filters go hand in hand, as the pump pushes the water through the filter. And some filters combine all three of these processes, while others focus on a specific type of filtration. Additionally, some pumps also offer built-in filtration.

What a Filter System Does for a Water Garden or Koi Pond

Regardless of the exact filter you choose, filter systems are vital to the health and appearance of your pond or water garden. There are a few key benefits to having a solar-powered water filter for your feature: 

Filtering Keeps the Water Clean

Although the water in a natural pond often appears still, in reality, it’s always in motion. Most natural ponds are fed by a freshwater source that keeps the balance of nutrients and organisms in check. Artificial ponds don’t have this luxury; as such, you need to install a pump and filter system to keep the environment clean. 

Ultimately, clean water is essential to a pond’s ecosystem. Unclean water promotes:

  • Bacterial growth
  • Ammonia spikes
  • Algal blooms

All of these issues can harm the living beings inside your pond. If you plan to introduce fish into the water, you must use a filter system; koi fish are particularly sensitive to environmental changes, so a clean pond keeps them happy.

However, even if you don’t intend to release koi or other fish into your water feature, a clean pond is still needed to keep your aquatic flora healthy. Algae can grow unchecked in an unkempt water garden, eventually impacting the oxygen levels that keep your plants (and fish) alive.

Filtering Keeps the Water Clear

Filter systems also have an aesthetic purpose: They keep the water in your pond looking crystal clear. When you consider that water gardens and koi ponds often act as decorative features, having clear water is almost as important as having clean water.

With that said, clear water also has a practical purpose in some cases. If your water garden has plants growing at the bottom, the water must be clear enough for sunlight to penetrate. When the water is murky or algae-covered, some aquatic plants lose the ability to photosynthesize and may die.

Filtering Eliminates Unwanted Odors

Finally, a filter removes the debris and bacteria that can cause your water feature to emit an odor over time. Algae and fish waste buildup are the leading causes of unpleasant smells; both can occur when your pond water remains stagnant. 

A clean, clear pond shouldn’t smell like much of anything. So, to fully enjoy your backyard water garden or koi pond, it’s worth filtering the water to keep odors to a minimum.

How to Choose a Filter System

Of course, it’s not enough to install any filter system in your pond—you have to choose the right filter. Here are a few tips for picking a proper filtration system. 

Consider the Filter Type

Remember that there are three types of filtration: Mechanical, biological, and chemical.

For a small water garden, a mechanical-only filter system should sufficiently remove unsightly plant debris and keep the water looking clean and clear. However, it may be worth investing in a system with mechanical and biological filtering, as mechanical filters don’t remove bacteria.

For a koi pond, it’s generally worth looking for a filter or filters with all three filtration types, as each variety promotes overall water health, which is paramount to a healthy fish population.

Choose a Pump That Suits Your Pond

The pump is the apparatus that forces your pond water through a filter to clean it. When choosing a pump, the size of your pond is the primary factor to consider. 

In a purpose-built pond, you need to circulate and clean the water every two hours. To that end, if you have a 700-gallon pond, you need a pump that can handle 350 gallons per hour. Anything less than that will not keep up with circulation, and your pond may become dirty.


Keep Your Koi Pond or Water Garden Clean and Healthy with Solariver

Ultimately, filtering your pond is a must—but you can’t have a working filter without a working pump. At Solariver, our solar-powered pumps keep your home water feature clean and clear by pushing pond water through your filter system. Even on cloudy days, a solar pump filters your water without the need for costly electricity.

A high-quality pump also keeps your pond aerated and oxygenated, providing an ideal environment for plant and animal life. Along with a proper filter system, the right pump allows you to enjoy your small water garden or koi pond for years to come.

To find the proper pump for your pond, view our stock of aerators and solar water pumps. If you have any questions, feel free to contact us—we’d love to hear about your project.