Filter Media

Filter Media

Ensuring a healthy water system

The filtration of your pond is paramount to its success. Healthy water with an efficient filtration system is one of the main factors that will allow your fish to thrive.

We carry a select range of filter media that has been tested and proven to work in many pond applications so whether your looking to make a moving K1 biological filter or whether your looking for a hard ceramic media to go in a shower filter we are sure you will find every thing you require.

Good bacteria colonise on the filtration media and as your pond water passes over the media the bacteria convert waste produced by your fish through the process known as the nitrogen cycle.

Nitrogen cycle diagram
  • Alfagrog


    Alfagrog filter media has a very high surface area making it an ideal material on which micro organisms can adhere and populate to create a superb inexpensive biological filter media. Alfagrog is made from a highly porous material that contains many thousands of tiny crevases and pockets allowing benificial bacteria to thrive. Alfagrog is a superb biological filter media whether used submerged in a filter bay or in a trickle shower filter.

    Key benefits of Alfagrog:

    • Extremly porous giving a very high surface area
    • Economical
    • Light weight
    • Non uniform sized pieces

    Weight: 15kg


  • Bacteria House Media


    Bacteria house media is made from a ceramic that has been heat treated at 1300°c for 60hrs. This tremendous amount of heat causes the ceramic to break its internal bonds thereby creating an extremely porous structure that has a much greater surface area.

    One of the key elements of bacteria house media is that it reacts in a seemingly ‘electrostatic’ manner with floating organic matter causing an increase in adhesion rate. This produces clear clean water.

    Water in its natural state creates multiple bonds with surrounding water molecules creating a cluster. The bacteria house emits FAR infrared rays that break the bonds of the neighbouring water molecules thereby allowing more oxygen to be dissolved in the water.

    We highly recommend bacteria house media for use in shower filters with high flow rates. It is an extremely hard filter media designed to withstand the force of water with high flow rates.

    Size: 10kg box


  • Shigure Logo

    Bacteria Home Far-Infrared ceramic media is made with the best ceramic resources, such astourmaline, silica and germanium. By heating it to very high temperatures of up to 1800 degrees celsius, a very porous mineral rock is created. This way, Far-Infrared Bacteria Home can accommodate vastly larger bacteria colonies.

    Organic solids and rotting material are broken down more quickly than with other filter media. Doing this, the medium maintains the ecological balance in your pond. Furthermore erosion of the filtration media is minimal and is pH-neutral.

    Bacteria Home Far-Infrared is suitable for use inside as well as outside, and is particularly effective when used as the filtration media for bakki showers, trickle filters, and aerated compartmented filters. For the best results, the water must be poured over the material very rapidly.

    Thickness: 70mm
    Length: 180mm
    Size: 10kg box

    10kg Bacteria Home Far-Infrared is comparable to 35 litres of filter medium.

    Please allow up to 1 week for delivery of the product after ordering


  • Shigure Logo

    Far Infrared Mini Bacteria Home is a unique ceramic filter medium. It can be used in both aquariums and ponds, both with fresh and salt water.

    High concentrations of good bacteria nestle in the microscopic pores in the rock. The bacteria improve the quality of your water and filter out any harmful particles such as nitrate, nitrite, and ammonia. All this, without influencing the pH-value of your pond or aquarium.

    Far Infrared Mini Bacteria Home is best used in a trickle filter or bakki shower.

    Diameter: 25mm

    15kg Far Infrared Mini Bacteria Home comparable to 25 litres of filter medium.

    Please allow up to 1 week for delivery of the product after ordering


  • Crystal Bio Filter Media


    Crystal Bio logo

    Crystal Bio is a unique, eco-friendly glass media, widely used in shower filters. It is heated in excess of 900°C, creating a hyper-connecting glass cell structure.

    50 litres of Crystal Bio weighs only 7.5kg, making this the lightest shower media on the market.

    Crystal Bio Filter Media provides an enormous surface area for bacteria which can be up to 10 times more than most plastic filter media which provides the bacteria with a protected area or static zone designed to be the perfect environment for micro bacteria.

    Once colonised each piece of Crystal Bio will contain millions of these micro animals, all filtering many thousands of times their own volume every minute, searching for their food source. These micro animals will feed on small particles such as, fish waste, dead bacteria, algae and organic matter.

    Crystal Bio Filter Media is an excellent biological media for pond filtration systems supporting high fish stocking densities. Crystal Bio Filter Media is also ideal for feeding regimes that are maximised for fish growth.

    Key Benefits of Crystal Bio Filter Media:

    • Massive surface area due to the interconnecting cell structure of Crystal Bio
    • Lightweight, making Crystal Bio a superb media for use in trickle filters
    • Every piece of Crystal Bio has a protected area or static zone designed to be the perfect environment for micro bacteria

    Available in:

    • 50L Box 30mm – 50mm
    • 100L Box 30mm – 50mm

  • Japanese Mat


    Japanese Matting is considered widely to be one of the best filter media available and is used extensively in Japan. It is a available in sheet form and can be cut to the desired sizes to fit your filter. Japanese Matting has a huge surface area and is recommended used submerged.

    It is intended to be used as a biological stage of a filter after the mechanical stage removing all the solids from the water. If installed correctly Japanese Matting is considered very low maintenance.

    Available in two sizes:

    • 1.2M x 1M
    • 2M x 1M

  • Evolution Aqua K1


    K1 media logo

    How it works
    Maturing the K1 Media bio-media is important because a delicate eco-system is naturally developing for the bacteria involved in the nitrification process. K1 Media provides the maximum active surface area for the bacteria to colonise, more than other types of static media. It is this process which removes harmful ammonia and nitrite from the water.

    How it is different to other media
    As the K1 Media moves within the filter, it causes the old dead bacteria on the outside to be displaced. This makes space for new younger heavier feeding bacteria to rapidly colonise. Within the wheel is a protected surface which enables colonies of bacteria to naturally follow their lifecycle, of maturing, dying and then fueling the latter stages of the nitrification cycle. K1 Media has been designed to provide the best possible habitat for both young and mature beneficial bacterial colonies.

    What is meant by ‘self cleaning’?
    Unlike foam, matting, or other forms of static filtration media, the K1 Media is designed to move freely within your filter. The constant chaotic movement of the air from your pump, causes the media to self clean and thus requires no maintenance. This allows the filter to reach optimum effectiveness without the disturbance of periodic cleaning, avoiding unnecessary loss of bacteria within the filter. 50 Litres of K1 media will handle up to 250 grams of food per day and for K3, 225 grams of food per day. For retrofit of existing filters, K3 media is the most suitable due to its larger size and ease of control.

    K1 Filter media is designed to be utilised in a moving bed filtration system. The filtration system requires an air pump to pass air through an air diffuser to achieve movement of the K1 media. We have included a simple guide to help advise on the required amount of air for a chosen amount of K1 media.

    Available in:

    • 1 Litre
    • 3 Litre
    • 25 Litre
    • 50 Litre
    50-75 Airpump 70
    75-100 Airpump 95
    100-150 Airpump 130
    150-200 Airpump 150

  • Evolution Aqua K1 Micro


    K1 Micro logo

    K1 Micro Filter Media
    K1 media has been used by Evolution Aqua in Koi filtration systems for a number of years. This new type of filter media, K1 Micro, contains all of the benefits of traditional K1 media but is extruded in a much smaller form. The small wheel shaped filter media pieces provide a significantly increased protected surface area per cubic metre when compared to standard K1 for bacteria to colonise. This makes K1 Micro an ideal filter media for aquariums of all types where high level biological filtration is needed. K1 Micro can also be used to replace existing filter media.

    Available in:

    • 5 Litre
    • 25 Litre
    • 50 Litre
    50-75 Airpump 70
    75-100 Airpump 95
    100-150 Airpump 130
    150-200 Airpump 150

  • Oase living water logo

    After extensive research & development, OASE have successfully re-developed the Hel-X Bio Media to increase its biological settlement surface area by an additional 13%, resulting in the launch of Hel-X 13 Biomedium.

    Hel-X 13 consists of individual housings which allow beneficial aerobic bacteria to settle and breed inside the protected casings, helping to biologically break down soluble waste within the OASE ProfiClear Premium Moving Bed Filter Modules or an alternate moving bed of your choice.

    Hel-X 13 allows a greater amount of bacteria to be contained within the same filter volume, resulting in more rapid breakdown of food and fish waste within the filter system.

    The unique Hel-X 13 helical geometry offers low flow resistance whilst providing maximum protected surface area which is perfect for maintaining a stable bio film. The bacteria and micro organisms which make up the bio film biologically break down food and fish waste within the filter system, resulting in healthy water for your fish.

    25 Litres of Oase Hel-X 13 Biomedia has the capacity to biologically break down 170g of food per day and also boasts 40% more settlement area than Kaldness K1 Media.

    • 13% extra surface area on the new Hel-X 13 media
    • Maintenance free self cleaning media
    • Rapid breakdown of food and fish waste
    • 955m²/m³ Settlement surface area
    • 806m²/m³ Protected settlement surface area
    • 40% more settlement surface than Kaldness K1 Media
    • 25 Litres of Hel-X 13 will biologically break down 170g of food waste per day
    • Suitable for all moving bed filtration


  • Oyster Shells


    Large Pacific Oyster Shell halves have been used for years around the world to help buffer and stabilise the pH of water and to maintain optimal water conditions in ponds. Oyster shells are used extensively in Japan where the water is usually very soft.

    Since the Oyster Shells will generally raise the pH level in your water, these should only be used in cases of low pH or soft water.

    Bag size: 5kg


  • Zeolite


    Zeolite is an excellent naturally occurring volcanic mineral that can be used with great success as a water treatment. Zeolite is utilised as an ion exchange bed purifying your pond water as it passes over it.

    Zeolite can be used as frequently as needed without harming your pond or precious fish.

    The recommended amount Zeolite is 5kg per 1500 UK gallons (6750 Litres) of water requiring treatment

    Rapid Ammonia Removal

    • Reduces toxic Nitrite and Nitrate levels.
    • Maintains the health and vitality of your fish.
    • Large 10-35 mm chunks.
    • Ideal for large filters.
    • Can be re-charged by placing in a saline solution.
    • Can be used for decorative effect in the pond.

    When to Use:

    • For best results, use throughout the year and recharge regularly.
    • Recharge and top up when water quality begins to fall.


    • Place into a filter bag and rinse under the tap before use.
    • Place in the filter in an area with a strong flow of water.
    • Test your water quality using test kits.
    • To recharge: prepare a salt solution (4 table spoons per gallon of water) and soak the chunks for 24 hours.

    Please place the zeolite inside a mesh filter bag for best use.

  • Media Bags


    Filter Media Sacks are a most useful for bagging up loose media such as Alfagrog.

    Made from plastic these very strong sacks are ideal for all filter media and can be fully submerged without degrading.The media bags are designed with a draw cord for quick sealing.

    Size: 85cm x 52cm approx


  • Plastic Media Grid


    Plastic media grids are a very useful item whether you are looking to convert an old filter to enable a moving bed or being more adventurous and creating your own bespoke filtration system. A well made and extremely durable product.

    Size: 27” x 16”


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Pond liner calculator

Use our simple Pond Liner Calculator to estimate the liner and/or underlay size required for your pond.

The result allows for an overlay either side of 30cms. You may wnat to increase or decrease this value depending on your pnd installation.

If you're not sure on what size you need then contact us and we can help.

Measurements are entered in meters. As an example if your pond is 254cm deep at its deepest enter 2.54.

The liner dimensions for your pond including a 30cm over lap are:

Liner length:

Liner width:

An interesting fact for you. The water volume of your pond will be:


UK gallons:

Rectangle Pond Volume calculator

Pond Diagram

Measure the length of your pond, the width of your pond and the depth of your pond in meters and enter the measurements into the Utopia Koi easy to use pond volume calculator. This will give the volume in litres.

If you're not sure on what size you need then contact us and we can help.

Measurements are to be entered in meters, for example: 543cm would be entered as 5.43.

The water volume of your pond will be:

Volume in Litres:

Volume in UK gallons:

Circular Pond Volume calculator

Radius Diagram

Measure the diameter of your pond (the distance across the pond at its centre) then divide the diameter in two to get the radius of your pond.

Now measure the depth of your pond and enter the measurements into the Utopia Koi easy to use circular pond volume calculator.

If you're not sure on what size you need then contact us and we can help.

Measurements are to be entered in meters, for example: 543cm would be entered as 5.43.

The water volume of your pond will be:

Volume in Litres:

Volume in UK gallons:

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