Best Pond Filter Media | Biological and Mechanical Media For Healthy & Clean Water

If you want to keep the pond you worked so hard to build happy and healthy, you’re going to need to use a high-quality filtration system.

Your filtration system will keep contaminants and harmful bacteria out of the water, but it can only work as well as the filter media you install into it.

A filtration system that uses low-quality filter media is going to increase the amount of work you have to do to maintain your pond properly. On the other hand, high-quality filter media will dramatically reduce the amount of work maintaining your pond requires.

This guide is designed to help you find the best pond filter media for your specific pond type and size, so you save money and spend more time enjoying your pond -- instead of maintaining it.

​What Is The Best Pond Filter Media?

​Since choosing the best pond filtration media can be such an involved process, we have gathered some of the best filter media available.

Each of the products below was hand-selected based on our experienced research and by compiling reviews from customers just like you.

​Different Styles Of Filter Media

​There are three main types of filtration media you can use in your pond: mechanical, biological, and chemical. Each type of filtration media will play a different role in the overall health of your pond’s ecosystem. All three should be used in conjunction.

1. ​Mechanical Filter Media
   

   ​Mechanical filtration is, precisely as the name implies, a mechanical method of removing debris and waste buildup from your water.
   
   As water is pumped through your filtration media, the media will collect larger debris to keep it from making its way into the pump and back out into your pond. Most mechanical filtration media operates like a pad, foam, or sponge that acts as a wall to keep large objects out.
   
   Your mechanical filtration media will need to be removed from time to time to free it of obstructions and prevent it from getting entirely blocked by debris. If the filter media becomes blocked, it could keep water from reaching your pump, which would cause your pump to fail.
   
   Mechanical media typically ranges between ½” and 2-inches in thickness. One common mistake people make is believing that a thicker media will work better than a thinner media. Thicker media could provide better filtration, but it will cause pressure to build up in front of your pump.
   
   As the pressure begins to build your pump could be starved of water. That means your pump could overheat and malfunction, potentially even catching on fire.
   
   The best type of mechanical filtration will use a variety of different thicknesses and densities of filter media.
   
   The first coarse layer will catch larger objects while a finer interior layer will capture the smaller debris from your water. The final fine layer will ensure that the only objects passing through the media will be treated by your biological and chemical filtration systems.
   
   This combination of thicknesses and densities will ensure your pump receives adequate flow and cooling while also removing a large majority of debris from your water.
   
   

2. ​Biological Filter Media
   

​Biological filter media is not focused on removing large pieces of debris from your water.

Instead, it works to help remove harmful impurities from your water. Helpful bacteria in biological filtration media will work to remove the harmful bacteria that comes as a result of nitrites and nitrates building up to toxic levels.

Biological filtration media harnesses helpful bacteria to create an environment where the same bacteria can thrive.

Biological filtration media provides a large surface for helpful bacteria to cultivate and grow. The more area you are able to provide, the better your helpful bacteria can do their job. This means they will provide more filtration when you create an environment where they can readily grow.


3. ​Chemical Filter Media
   

   ​Chemical filtration may not necessarily be one of the most common types used for pond keepers, but that doesn’t mean you should neglect it. It is an active part of the process of removing harmful bacteria and keeping your pond healthy.
   
   Chemical filtration works to remove harmful chemicals, such as ammonia and chlorine, from your water. Mechanical and biological methods do not usually remove chemicals.
   
   You want to ensure that pesticides, odors, pollutants, and organic protein are not given an environment where they can thrive or begin to grow to uncontrollable amounts. This would require a complete water change.
   
   When it comes to removing harmful chemicals and preventing them from building up in your water, nothing works better than activated carbon. As time goes on, activated carbon will keep toxic chemicals under control and keep your water changes to a minimum.
   

What Filter Media Should You Use?

Now that you understand the three different styles of filtering your pond’s water, choosing the right type should be easier to do.

The answer to this question ultimately depends on the size of your pond and the level of filtration you require. We recommend that you utilize all three types of filter media.

At the minimum, you will want to use both biological and mechanical filter media together.

Mixing three different types of media helps you:

• Maintain a crystal clear pond free of toxic bacteria.
• Keeps the amount of large floating debris to a minimum.
• Reduces the number of harmful chemicals in your water.
• Helps create an environment where beneficial bacteria can thrive.
• Promotes a healthier ecosystem that is easier to maintain.

The amount of each type that you use is entirely up to you, based on the size of your pond, whether you have fish and plants, and the kind of water you’re using.

We recommend using a few layers of mechanical filter media, ranging from coarse to dense and fine with different thicknesses of each. Combining these with biological media to promote healthy bacteria is a smart choice.

If your pump is showing signs of flowing less water, you will want to remove some of the mechanical filter media. On the other hand, if your pond is turning green or developing an odor, you will want to increase the amount of biological filter media you are using.

The general rule of thumb is to monitor your pond’s water for changes as you begin to change and cycle your filtration media. As long as your pump is flowing a sufficient amount of water and your water’s color or smell is not changing, you have the right combination.

If you notice that you are consistently dealing with green water, algae blooms, or an odor in your water, you could have more significant issues than your filter media can address. This means you will need to perform regular water tests and address the more significant areas of concern.

What Is The Best Combination Of Pond Filtration Media?

To maintain a healthy pond, you are going to need to clean your filter media periodically.

Whether you have created your DIY filter media or you are using pre-bought filter media, the method you use to clean it should be relatively similar. Now that you understand the role that your filtration system plays on your pond, we’ll get into proper cleaning techniques.

If you haven’t already purchased your filtration media, pick one of each type of the products listed above and combine them into a working system. Make sure that you are layering your mechanical media in the way we have laid out: coarse, dense, fine.

Then, add a layer of activated carbon and biological filter media to ensure your pond remains clear, healthy, and free of harmful bacteria.

How To Clean Your Pond Filter Media

There is going to come a time when you need to maintain your filter media. Proper cleaning techniques can help you save money by avoiding replacing the media.

If your pond is healthy and bright, you can typically clean the filtration system a few times per year. However, if you notice that the pump is not flowing enough water or the water clarity is beginning to fluctuate, you will need to perform maintenance more often.

The easiest way to determine your maintenance schedule is to take a quick peek at your mechanical filter media. If you notice that there is a buildup or a thick layer of debris, then it is time to begin cleaning the media.

Your biological media, though, will typically only need to be cleaned when it becomes clogged or packed with debris. Biological media will develop a brown color as harmful bacteria begins to build up.

Without proper maintenance, this harmful bacteria can begin to offset the healthy bacteria and spread into your ecosystem. That means you will need to clean the biological filter to ensure the healthy bacteria has a chance to survive.

You want to avoid cleaning the media too often. As you own your pond for more extended times, you will begin to develop a natural maintenance schedule that keeps your filter media operating at peak efficiency.

How To Clean Mechanical Filters

To clean your mechanical filter, you’ll first start by removing the pads from your system. Then, place the pads into a bucket or hose them off with your garden hose.

You don’t have to worry about washing bacteria off of the material since mechanical media is solely designed to stop dirt, debris, twigs, leaves, and other large objects.

You do want to ensure you can flow water through the media again, though. Removing all of the built-up debris from the mats, pads, and foam will help keep your pump operating at peak efficiency, too.

The finer, more dense filter media will always be harder to clean. You can judge how well you’ve cleaned it by the amount of water flowing through it. Water should be able to flow freely through the media once it is clean.

After you have correctly removed the built-up debris and gunk, you can reinstall them into your filtration system.

How To Clean Biological Filters

Biological filter media may need to be cleaned more often. When it begins to get clogged, the helpful bacteria will stop doing their job.

To clean your biological filters, you will need to remove the media from your filtration system and wash it off in a bucket of water taken from your pond.

The pond water is a requirement because the beneficial bacteria can be reintroduced into your pond once you are finished cleaning the filter.

Something to keep in mind is that you may need to remove blockages on your biological filter media physically. If you have removed all of your helpful bacteria, you will need to add a beneficial bacteria back to the media before reinstalling it into your filter.

How Often You Should Replace Your Filter Media

• Mechanical filtration should last for quite a while if you are purchasing quality media. It is not uncommon for mechanical filtration media to last 2 to 3 years before needing to be replaced. If you regularly clean and maintain your pond, your filter media could last even longer. If you notice damage, tears, or frays, replace the media with new stock.
  
  
• Biological filtration media will rarely ever need to be replaced. As a general rule, you should only replace it if you notice damage, rips, and tears while you are maintaining your filtration system.
  
  
• Chemical filtration media will need to be replaced far more often. You will typically need to replace it at least once a month. If your pond stays clean and bright, though, you can get away with replacing your chemical filtration media every 2 to 3 months.