Koi Fish Ponds

Latest Articles About Koi Fish Ponds

What Happens Inside A BioFiltration System

How Does A Biofilter Work

A proper and efficient Biofiltration system is the key to a healthy Koi fish pond. Before the introduction of any fishes, it is vital to confirm whether the biological filtration in your pond is working optimally.

So that the koi fish in your pond remains healthy and you can enjoy your Koi fishes day after day. Here is a summary about what happens inside a biofilter.

The most important of all the filtration cycle is the nitrogen cycle where the Ammonia generated by the fishes urine and excreta is converted into non-toxic Nitrates.

It is the process in which beneficial bacteria becomes established in your pond's filtration system and will effectively help in the conversion of toxic Ammonia

The cycle begins when the fish eat the food passes through its digestive system and excretes. Ammonia is one of the main toxic chemical contained in the fishes excreta. Ammonia is also generated when the excess food and other organic matter like leaves etc start to decompose.

What happens inside a Biofilter?

1. Water with High Ammonia enters the Biofilter.

The bacteria present in the biological filter media called Nitrosomonas eats the ammonia and converts Ammonia to Nitrite. Since both Ammonia and Nitrite is toxic to fish it needs to be removed from the water as soon as possible. This is why we keep the turn over the period at the maximum possible rate. i.e, for koi fish ponds it is ideal that the total water volume is rotated once every hour.

2. Water with nitrate content passes through the next chamber.

Here another type of Bacteria called the Nitrobacter which lives in the filter media eats this Nitrite and releases Nitrate which is not harmful to fishes. Nitrate is also a very good fertilizer for plants.

3. This entire cycle then repeats itself upon completion.

The Nitrogen Cycle often referred to as "cycling" is the most important process when first starting your pond. When starting up any pond start by introducing fewer numbers of fishes so that the biological/beneficial bacteria have enough time to form colonies and establish them self s. This process takes normally anywhere between 4 - 6 weeks.

Always measure the ponds ammonia and PH level using test kits available if you cannot find good ones we can provide you with test kits. If your filtration is fully cycled correctly you should have Zero Ammonia and Nitrite and the Nitrate reading should be somewhere in the 10-35ppm range. This is a very good sign.

Since your koi pond is a closed recirculation system and If there is a malfunction in the ponds filtration system it will increase the stress levels of your Koi fishes which will be sometimes difficult to spot. If not spotted on time it can cause severe damage to the internal organs and finally will cost the life of your dear pet koi fish.

Building Biofiltration systems for your koi pond are our speciality, connect with us for more information.

To read more about building garden water features and Koi Fish Ponds follow the links below.


KJA & Sons - Engineers and Contractors
CC – 15/ 68 A, West Karuvelipady, 
Kochi – 682005

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