• Biological Filter
• Ammonia Cycle
• Water Planting Scheme

After debris and algae were removed by a mechanical filter, the water will be channelled to another filter called Biological Filter where organic pollutants to be converted to harmless substances. It's primary function is converting ammonia from fish wastes (and to a lesser extent, from decaying plant matter and uneaten fish food) into nitrates, which can be absorbed by plants as a nutrient.

By design, construction of the Biological Filter consists of two or layers of gravel or other medium with a large areas that harbor a huge amount of concentrations of beneficial nitrifying bacteria. As water slowly flows through the medium, these bacteria break down toxic ammonia (and nitrites, which result from partial braekdown of ammonia) into nitrates.

Anatomy of a biological filter can be described as below;

• An aeration tower - dirty water is pumped from the pond through the aeration tower from the top to the bottom of the filter
• Filter Media - the presurrized water moves upward through the Filter Media slowly (giving the beneficial bacteria to eat up on their fill). It exits near the top of the filter and through a return pipe to the pond. The return pipe can be hooked up to a waterfall.
• Submerged plants in the top of the media- to provide additional oxygen to the bacteria and to absorb nutrients.

Unlike mechanical filters, biological filter do not require a high flow to operate efficiently. The pump needs to turn over the total volume of water only once every four to six hours.

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Food > Fish > Pond Waste (Ammonia) > Nitrifying Bacteria (Nitrite)> Nitrifying Bacteria (Nitrate) > Plants Grows > Food (Back to first cycle)

After food were consumed by the fish, and organic materials decays, ammonia was produced. Ammonia is toxic to fish in sufficient concentrations.but can broken down by Nitrifying Bacteria to Nitrites. These aerobic Nitrosomonas bacteria use up oxygen as they convert Ammonia into Nitrites, if anything even more toxic to fish Another type of aerobic bacteria called Nitrobacter then continue the process, converting Nitrite to Nitrate which is a plant food and far less damaging to the fish.

A well designed, well maintain filter provides an ideal home for these bacteria. It offers somewhere comfortable to live with a constant flow of well-oxygenated water and the all important supply of adequate amount of ammonia and nitrites to convert.

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The most important factor in planting your pond is the effect that plants will have on the water quality. Large surface coverage of aquatic plant leaves on the pond bring about a more clear, natural pond.

The roles of plants in and around the pond.

• Oxygenators
• Floating Plants
• Deep water aquatics and water lilies
• Marginal Plants
• Bog Garden Plants

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