Koi Pond Filtration – The Pros and Cons

You must first understand that there is Filtration and then there are Filters. Filtration is basically the type of filtering that a system performs, be it Mechanical, Chemical or Biological. The filter is the actual unit that does the work. Let’s first discuss the different types of filtration.

Mechanical Filtration – refers to the removal of large and small particles through a material that traps the particles. This is a very important part of any filtration media. Mechanical filtration helps clean pond water of solid debris such as uneaten food, dry leaves, feces, and plant debris before it reaches the bottom of the pond or aquarium, thus keeping the water free of decomposing substances that can later produce harmful chemicals. Mechanical filters sometimes come with skimmers to catch large floating debris; This is followed by a filter that catches the smaller debris and prevents it from entering the pump. Therefore, a mechanical filter can be considered the most important part of pond or aquarium filtration.

chemical filtration – refers to the use of chemicals to remove chlorine, pesticides, heavy metals, ammonia, and other chemical impurities from pond or aquarium water by chemically bonding them to filter media, such as activated carbon.

Biological Filtration – refers to a filter that provides a place for beneficial bacteria to grow, helping to remove contaminants from the water. You will need to add material like mats or gravel for the beneficial bacteria to live in, which is one more item to maintain. Also, if you use the wrong type of water, such as city water to clean the biological filter, it can kill beneficial bacteria. A biological filter will take weeks or months to mature enough to provide any benefit to your pond or aquarium.

Now let’s discuss the type of filters.

sand filters – although they are sometimes highly recommended for ponds, they should really only be used for swimming pools. They are not able to trap all the debris in the sand, allowing untrapped particles to re-enter the water. They are extremely difficult to clean as they must be backwashed daily, which causes significant water waste, and must be run 24 hours a day for the best filtration. Also, if you have hard water, it can cause sand to collect in the bottom of the tank and reduce filtration.

organic grain filters – these are very similar to the sand filter, except that they are even more difficult to clean.

Submersible filters – they are difficult to maintain as you may have to wade into the pond to retrieve the filter for cleaning. Filter debris can spill back into the pond during cleaning.

Cartridge filters (Pool Filters) – Although most people balk at the idea of ​​using a pool filter for their Koi pond, we’ve found that they are the best filters overall. They filter 99% of debris, are very easy to clean and last a long time. You can also use them for aquariums.