Selecting the Right Filter Media

Published on July 1, 2010

1_filter_media_aqua_ultravioletWhen choosing a pond filter media to use in a biological pond filter it is essential to consider the Specific Surface Area (SSA). The higher the biomedia’s SSA, the more effective it will be in colonizing nitrifying bacteria. In essence, the role of any pond biofilter is to convert ammonia, produced by fish waste, excess fish food and decaying vegetation into much less harmful nitrate in a process known as the Nitrogen Cycle. Any biological filter is only as good as the bio media used. The higher the number of beneficial bacteria living on the pond filter media the better quality the pond water will be. By selecting a pond biomedia with a high SSA you will in time save yourself and your clients, a lot of time and $$$.

Choice of Pond Filter Media is Important

When selecting media, the SSA helps you decide how much media volume you will need to process the fish load you are expecting in the pond. If a media has a low SSA, you will need to have more of it. This may not be a bad thing, depending on how much space you have available, and how important ease and frequency of cleaning is to your client. Ease of cleaning is different for every media, so that may be more important to your client than how much space must be set aside to house the media.

It is the bacteria living on the media that do the work. Keeping them healthy is vital.

Aqua Ultraviolet
Look after the beneficial bacteria living on the biomedia, as failure to do so can have very negative effects on the water quality within your pond. Minimize the potential for growing unhealthy or unwanted bacteria in your pond by staying away from anaerobic conditions as far as possible (low oxygen conditions).

Pond water conditions and low oxygen levels easily affect beneficial pond filter bacteria. (Lack of oxygen for eight hours will result in total eradication of the colonies living on the pond filter media.) It can take several weeks or even more for the colonies to reform on your pond filter media. Nitrobacter and Nitrosomonas are pH specific and do best in water with a pH between 7.5 and 8.6. They are further affected by temperature and chemicals added to the pond water.
(Also see at end of article – The Nitrogen Cycle Process.)

Filter Media by Brand

*(that the author has accumulated over the years)*

Aqua Ultraviolet 8.5lb White Pond Filter Media

Aqua Ultraviolet Ultra Bio Media is a filtration media with a very high bio film surface that offers superior bacterial adhesion and colonization. Features … Excellent flow-through within the media … Patented “Y” shaped media. Aqua Ultraviolet Ultra Pond Filter Material is a premier choice for biological filtration.

Atlantic Filter Falls BioBag Pond Filter Media

Atlantic Filter Falls BioBag comes with 1 cubic foot of Bio Tech Filter Media. Promotes the growth of water filtering bacteria.

Bacti Twist Pond Filter Media

This black, spiral shaped plastic filter media has been designed for filtration in garden ponds and other aquatic systems. Loose fill media will fit into any filter box or pond filter, including up-flow filters, trickling biofilters and pressurized filter systems. This filter media provides a large surface area of 95 square foot of space per cubic foot for beneficial bacteria to colonize. Each cubic foot of Black Bacti Twist Pond Filter Material is packaged in a black nylon mesh bag. Bacti Twist comes in different widths, depending on the water flow desired, as well as the colors black or white.


From the large Aquaculture industry to the home hobbyist, Bio-Bale is the filter media of choice for professionals. Simple in concept, Bio-Bale owes its extreme effectiveness to its high surface area versus volume and its unique surface texture. With 250 square feet of surface area per cubic foot and 33 square feet per gallon, Bio-Bale cannot be matched. Bio-Bale is produced from one continuous piece of F.D.A. approved, non-toxic plastic designed specifically for CPR. Bio-Bale is measured precisely by computer to achieve a consistent surface area. VERSATILITY Bio-Bale’s unique structure allows it to be used in any size or shape biological filter, making it ideal for custom or commercial filters. Because it is actually a single continuous strip of inert plastic, cleaning and handling it is easy.

Bio Wave Media

The Bio Wave Media is high quality, energy efficient, and high performing. They are designed to preserve the delicate useful bacteria during backwash, and to provide a large surface area for the bacteria to live and flourish. Use the Sinking Media to make your own filter or replace the sand in a sand filter. They work well with 2-Speed water pumps. Switch on High Speed for higher pressure filter-cleaning purpose only, and use the Low-Speed for daily operation. For a single Low-Speed pump, use an air blower to help push the air into the water.

BIO-ACTIVE Stone Media by Matala

This media is a highly porous stone ceramic media with incredible surface area. Bio-Active contains literally acres of surface area per cubic foot. The stone is ideal for use in trickle aerating towers similar to the BAKI shower or as a submerged bed. The mineral composition will refresh and polish your water. Use it as a final stage after Matala filter pads to stabilize your ponds chemistry and replenish minerals. Available in five different sizes.

Biomate Solids Biological Media Balls Ceramic Sphere Biomedia

BioMate Refillable Media Balls provides maximum surface area with the greatest possible mix of air and water. Cultivates nitrifying bacteria. Promotes gas exchange, increases dissolved oxygen levels and removes harmful gases. Will not clog with organic matter. Manufactured from the highest grade of thermoplastic material. Each ball is approximately 1.5˝ in diameter and is totally inert and non-leaching; containers are 1-gallon size. This ceramic sphere pond filter media is available as … Biomate Carbon Purify Aerate 75 Piece … Biomate Foam Clean Aerate 75 Piece … Biomate Ceramic Biological Aerate 75 Piece … Biomate Filter Boost Combo Ceramic Carbon Balls … Biomate Solids Biological Aerate 225 Piece.

Blagdon Pro Ceramic Biological Media

Blagdon Pro Ceramic Bio Media is ideal for multi chamber filters, shower/trickle filters, and box and pressure filter systems. Designed to support high fish stocking density. Enables high growth rate feeding regime. Very high surface area ceramic bio media. Extreme porosity. Size: rib length 27mm/1.063˝ width 31mm/1.22˝

EasyPro Bio Balls Black Plastic Pond Biomedia

Easy Pro Bio Balls is a loose plastic biofilter media that will form to any shape and is hard, so it will not compact. Ideal media for deep applications where compaction is a concern. Bio Balls are buoyant so trickle filter applications are best. Bio-Balls are 1.5˝ in diameter. Easy Pro Bio Balls Pond Filter Media is available in the following sizes … EasyPro Bio Balls 1 CU FT … EasyPro Bio Balls 4.50 Cubic FT.

EasyPro Bio Blox Cheap Pond Biomedia

Easy Pro Bio Blox Pond Filter Media is an ultra high surface area media that is created from a variety of different filter thicknesses and densities. Bio-Tech is a loose fill media that is inexpensive and ideal for filling large filters. Use a mesh bag to hold Bio-Tech for easy handling. Approximately 525 sq. ft. of surface area per cubic foot. Easy Pro Bio Blox available sizes … Easy Pro Bio Blox 1 CU FT … Easy Pro Bio Blox 24 CU FT.

Emperor Aquatics FilterClay Media

FilterClay Media combines its 4-8 mm size, specific weight and shape to help eliminate media-packing inside the filter. Additionally, FilterClay’s porous skin and core make for ideal bio-filtration conditions.

Filter Brushes

Japanese in origin they are suited for both mechanical and biological filtration. As pond water passes through a series of brushes, the bristles filter out suspended solids, while providing ample surface area where the nitrifying bacteria can colonize and thrive. Cleaning of the filter brushes is a simple task of removing them from the filter and shaking them out. Remember not to use tap water to rinse them, as this will only serve to reduce or eliminate the beneficial bacteria, which is growing on the brush.

Fishmate Supra Pond Filter Media (ALFAGROG in UK)

A porous inert filter media possessing over 100 times the biological surface area of conventional plastic media and suitable for use with all ponds and aquariums.

GC Tek Alpha ONE Plastic Filter Media Beads

GC Tek Alpha ONE plastic Filter Media Beads float. The more buoyancy that the beads have – the better. To increase buoyancy the manufacturer has added air to each individual bead during the manufacturing process. GC Tek Alpha One Plastic Filter Media Beads will stay as close as possible to the top of the filter during backwash. The surface of the bead is dimpled to add more surface area, on which beneficial bacteria can colonize.

GC Tek BioGems Aquabead Floating Bead Filter Media

These biological floating plastic filter media beads are filled with air during the manufacturing process. These beads will stay as close as possible to the top of the filter during backwash. The surface of the bead is dimpled to add more surface area, on which beneficial bacteria can colonize. GC Tek BioGems Filter Media available Sizes … BioGems 0.25 CU FT Bead Filter Media … BioGems 0.50 CU FT Bead Filter Media … BioGems O.75 CU FT Bead Filter Media … BioGems 1 CU FT Bead Filter Media.

Laguna BioMax Pond Filter Media

Laguna BioMax Biological Filter Media provides a large surface area for beneficial nitrifying bacteria to colonize. Helps to maintain healthy, biological conditions by removing toxic ammonia and nitrites. Easy to clean. Laguna BioMax Pond Filter Media is supplied in a 350g Box.

Matala Round 22˝ Roll Filter Media

Matala Round Roll Filter Media is 22˝ in diameter and fits most whiskey barrel style biological pond filters. (Seven diameters are available: 22˝; 24˝; 27˝; 30˝; 37˝; 42˝ and 48˝.) The Black Matala® can be used as a support grate for other layers of media due to its very sturdy and open design. In a settling chamber the Black will slow down and trap very large particles and hair algae. When you use the Black or Green Matala® filter mats for solids’ filtering you may use the garden hose to spray clean them. The dirt falls off very easily. Matala Round Roll Filter Media is available in the following specifications and colors… Black Super Coarse … Green Coarse … Blue Fine … Grey Super Fine.

Matala Pond Filter Media Sheets

Matala Pond Filter Media Sheets are an extremely durable and hardwearing bio-filter media. This versatile pond filter media can be used in bio-filters, settling tanks, and pond pump pre-filters. Simply cut to size using a pair of scissors or serrated kitchen knife. Matala Filter Media Sheets are available in either Half Sheets or Full Sheets and in the following colors … Black Super Coarse … Green Coarse … Blue Fine … Grey Super Fine

Misty Mountain’s Bio-mate

Bio-mate is a long lasting hardy synthetic and affordable. It is easy to clean and works perfectly with our nationally known biological media, fish floss. A full 1.5 inches thick. It is easy to cut to fit most existing filters; i.e. waterfall boxes, enclosed, pressure, up flow, down flow, and side flow. Expect many seasons of easy cleaning with this media. The ease of cleaning is due to the closed cell design that does not allow debris to imbed into the media.

Open Cell Foam

Reticulated polyurethane foam is a versatile material that can be fabricated or combined with other materials into virtually any configuration. It is used on, in, or around products serving consumers, business, industry, health care, research, and the military. How does polyurethane foam become reticulated? It is subjected to a proprietary process inside a specially designed vessel using heat and pressure to create flexible skeletal foam structures without cell membranes. Open cell foam has a large amount of surface area for beneficial biological capacity.


White polyester fibers mated into a 2˝ thick material. Use as a second stage in your pre-filter or as a bio-filter media. An excellent versatile media. Washable for repeated use.

Savio Springflo Pond Filter Media

Savio Springflo Bio-filter Media is a polypropylene and calcium carbonate ribbon. The embossed diamond pattern creates millions of dimples to rapidly secure and develop beneficial pond biofilter bacteria. This low filter media is easy to use and maintain. Benefits include: Resists channeling … Resists clogging and compaction. Each box provides 180 square foot of surface area. Savio Springflo Bio-filter Media fills 2 to 3 cubic ft.

Savio Springflo Pond Biomedia Mesh Bag

Savio Springflo Pond Filter Biomedia is available as a mesh bag system that makes it possible to use Savio Springflo hybrid technology in a variety of filters. The Savio Springflo Pond Biomedia Mesh Bag can be used to update any competitive filter that operates with bio balls, lava rock, or filter mat.

EDITOR’s Note: Momotaro Koi Farm of Japan sells a highly regarded media, known as Bacteria House. It has a very high surface area, popularized for use in their Bakki Shower filter system.*


When considering a media for a filter system, be sure to look into all the characteristics of the media. Does it float, or sink? What do you need to build into your system to clean it? Air jets, water jets, bottom drains or backflush plumbing. Every commercially available media will work to some degree for a period of time. How it performs over time is as much about the design of the filter you put it in, as the media itself. Do your homework and it will be time well spent.

The Nitrogen Cycle Process

The following two equations show the chemical process required in order for conversion of ammonia by beneficial bacteria (Nitrosomonas and Nitrobacter). Note the large quantities of oxygen needed.

For Nitrosomonas: 55NH4++ 76O2 + 109HCO3- —> C5H7O2N + 54NO2- + 57H2O + 104H2CO3

For Nitrobacter: 400NO2- + NH4+ + 4H2CO3 + HCO3- + 195O2 —> C5H7O2N + 3H2O + 400NO3-

An important point to note is the large volumes of oxygen needed. This factor is further compounded in warmer climates, such as those found in the southern states of the USA. As pond water temperatures increase it becomes increasingly more difficult for oxygen to dissolve in the water. 4.3 mg of oxygen is required by Nitrosomonas and Nitrobacter beneficial bacteria when converting 1 mg of ammonia into nitrates.

A garden fish pond is a living, breathing system where only a few degrees rise in pond water temperature results in the following sequence of events: Warmer water results in increased koi and pond fish metabolic rates, resulting in a higher need for food, which results in more biological waste, which places a greater load on the biological filtration efforts of your pond filter.

Koi living in warm pond water may excrete between 50 and 100 mg of ammonia per kg of body weight per day. That is an awful lot of NH3 (ammonia). The level of ammonia is further increased by the amount of waste produced by koi as they eat. Koi are extremely ravenous fish and will consume large amounts of food, given a chance. This solid waste will start to decompose on your pond floor, giving off ammonia.

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6 thoughts on “Selecting the Right Filter Media”

  1. I need a media for biological filter, for pond who have 2000 litres and have carps in it. Not koi carps, carps from river. Can you tell me which media is the best??? Thank you. Robert

    1. Avatar photo
      Lora Lee Gelles

      Hi Robert.
      Here is an answer for you from Richard Heimberger of Healthy Pond:

      Robert, the best media has a lot of surface area. It is light weight and simple to maintain. It should also be easy to work with and easy on the wallet. Things like bioballs, Kaldnes, and PVC shavings are popular but expensive. My favorite is media bags filled with the strapping material used by shipping companies. It comes in black with a waffle pattern and costs around $50. I roll fills 6 media bags. Works well in trickle towers, upflow filters, and many other systems. It also cycles quickly.

    2. Avatar photo
      Lora Lee Gelles

      From Mike White:
      Not sure where you live, but all the carps from the U.S were put here in 1876, and were grown and distributed by the U.S. government. All the natural carp in the rivers came from Germany, who got them from China, which are basically the same carp that koi were developed from. There is no such thing as “the best” media. It depends on the application or the filter that the media is being used in.

    1. Avatar photo
      Lora Lee Gelles

      From Mike White:
      Yes, you can use a pool filter, but it will clog up very, very quickly. A pool filter is designed to work with clean water. A pond has so much particles and debris in it, that it clogs. It will become worthless in a matter of minutes, not hours. You will want to use a filter that is designed for catching large particles and not fine particles that will go longer periods of time without clogging up so you have some chance of cleaning up a pond initially so you can get to a point where you can use a finer filter to get your water clarity. Or you can empty the pond completely and put fresh water in.

  2. The right pond filter media is a most important thing of a pond. For purifying the water of pond we have to use the right pond filter. Every pond needs a good filtration system. We also have to know how to clean a pond filter. A lot of information here I have got. Thanks for this article.

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