Pond Filters and Filter Media The filter is of key importance in keeping your Koi pond water crystal-clear and free of chemical pollutants. Our line of filters are designed to meet a wide ra

Three Stages of Pond Filtration

The filter is of key importance in keeping your Koi pond water crystal-clear and free of chemical pollutants. Our line of filters are designed to meet a wide range of needs, for both large and small ponds. Our line of filters provide one or more of three types of Pond Filters and filtration are:

  • Biological Filtration
  • Mechanical Filtration
  • Chemical Filtration

Pond filters are fundamental equipment essential for clean, clear and healthy pond water. Choose from our selection of quality filters to suit the needs of your pond or water garden.

There are three pond filter media types to provide mechanical, chemical and biological filtration. To maintain clean, clear and healthy pond water, employ all three types of filter media.

Mechanical Pond Filtration: Refers to the physical removal of debris from water by materials that trap large and small particles. Polyester Pre-Filter Pads last longer and filter better that other pre-filtration products, even after several cleanings.

If your pond is solely ornamental or you are looking for a pre-filter for your pump, then you will probably find the need for a mechanical filter.

A mechanical filter is solely designed to separate large particles and debris from the water passing through it. This is particularly advantageous when protecting a pump. When run through a mechanical filter, water will not be treated and will retain any toxins or harmful substances it contained prior to entering the filter. As such, mechanical filters are not recommended as the only source of filtration for a pond containing fish or aquatic wildlife.

Most filters available will feature at least some degree of mechanical filtration in addition to their specialized function. Skimmers, canister filters, and prefilters are common examples of filters that mainly rely on mechanical filtration.

Chemical Pond Filtration: Removes pesticides, colors, odors, organic waste, excess nutrients and other harmful chemicals from your pond. Coconut Shell carbon, Zeolite are examples of products to be used in your filter for chemical filtration.

Biological Pond Filtration: This is where your pond filter provides a place for beneficial bacteria to grow on special media. These bacteria remove harmful pollutants from pond water. Known as the "Biological Filter" these beneficial bacteria convert poisonous compounds such as ammonia and nitrite, into less toxic nitrate. The end by-product, nitrate, is used as a food source by aquatic plants. This continuous process is called the nitrogen cycle.

Biological Pond Filtration relies on specific bacteria to break down toxic waste products to less harmful substances. There are two stages in the breakdown of ammonia, each stage involving different types of bacteria. The first stage is the breakdown of ammonia to nitrite by nitrifying bacteria, most important of which is Nitrosomonas. The second stage is the conversion of nitrite to nitrate by Nitrobacter.

Both of these groups of bacteria are aerobic (needing oxygen to live), sediment building up in the filter will deplete the oxygen levels so it is important to keep sediment to a minimum by having a settlement chamber first and by cleaning the filter out occasionally (but not using tap water as the chlorine will kill the bacteria).

A variety of different media are available to put in the filter, materials such as gravel, matting, hair rollers, foam, and canterbury spar are all suitable as they provide lots of surfaces for the bacteria to live on.

A biological filter will take weeks or months to mature, cultures of nitrifying bacteria are widely available and will speed up the process.

Filtration Type Helps Eliminate:
Algae Debris Discoloration Toxins
Biological X X
Mechanical X
Chemical X X X


Pond Filters and Filter Media

The filter is of key importance in keeping your Koi pond water crystal-clear and free of chemical pollutants. Our line of filters are designed to meet a wide ra