Koi pond filters need excellent biofiltration. Your large koi need large koi pond filters

Koi ponds and koi pond filters dedicated to growing large koi are not the same as garden ponds needing simple small koi pond filters. Koi ponds tend to be deep and high volume. Large koi eat lots of food. Large koi need extra oxygen and a highly efficient koi pond filter design with equally efficient biomedia in the koi pond filters to cope - the ideal is japanese matting inside a vortex filter.

Koi pond filters design especially vortex types of koi filters needs very special attention. Please note here that I am talking about the koi enthusiast – people who build 10,000 gallon ponds and buy very expensive koi or grow small koi up to big koi.

I am not talking about homemade water garden pond filters for the small koi pond enthusiast who has a pond of about 2,000 litres (500 gallons) or less.

It is also not my intention to debate at long length the merits of a particular type of koi fish pond filter compared to other koi pond filters or fish pond filter. My book does go into detail on koi pond filters and their requirements.

Koi Pond Filters

I am taking this opportunity to dissuade people from using sand filters for a koi fish garden pond filter even as so called "polishing koi pond filters". I do want to prompt the real enthusiast go in the direction of vortex koi pond filters using japanese matting or something similar. I am also not going into any details about specific design criteria. I will give my views based upon my chemical engineering knowledge and discussions with world leaders in the koi field (or should it be koi pond?) like Nigel Caddock and Peter Waddington over many years. You will be left to search the net to satisfy any longing you may have to learn more and there is lot to learn.

“I have read your book with interest and have found it most interesting. I wish I had read it before constructing my pond” Gordon Powell, seaview@scottburgh.co.za

For 10 years fish pond filters problems solved for happy customers.

Koi fish food can contribute greatly to poor pond filtration

Sand filters used as koi pond filters or in any part of a koi pond filter system are bad news: 

Sand filters are great for swimming pools and very bad for all fish ponds but especially when used for koi pond filters. These are the reasons:

Sand filters are expensive to operate as koi pond filters in terms of running costs since high pressure pumps are required.

Sand filters create disease problems when used as koi pond filters because the as bio filters they cannot be cleaned well enough to prevent pathogenic bacteria formation in dead spots in the sand filters. See article on pathogenic bacteria by Tom Holder.

There is a need for biomedia somewhere in the koi pond filters system anyway - sand is a very inefficient koi pond filter biomedia.

Sand filter back washing systems are not sufficiently effective to even start cleaning to the standard required of koi pond filters. In addition they waste massive amounts of water.

It is not possible to add air to koi pond filters of this type. Large koi pond filters need massive air quantities to get the appropriate level of biofiltration to occur quickly - especially after feeding.

 Sand filters are used because they are easy to install for large pond volumes and low in terms of capital cost. They are bad koi pond filters. This is my reasoned conclusion.

Vortex koi pond filters and japanese matting koi pond filter media: 

These are ideal koi pond filters based upon extensive practical knowledge and worldwide use - and even favoured in Japan. Vortex koi pond filters are discussed more often than not in the context of use with japanese matting. Japanese matting is an open celled structure supplied in sheet form. It is cut into sections and placed in a type of lattice pattern at the top of vortex koi pond filter units around which a massive amount of air is blown continuously. This type does not lead itself to making homemade koi pond filters or diy koi pond filters.

Japanese matting works so well because massive amounts of air can be blown into the voids around the open structure created by the japanese matting lattice structure. This creates a very high SSA (specific surface area) for bacteria colonisation. The turbulence associated with high oxygen levels and large surface area is what makes this type of biofilter perfect for koi pond filters. The system obeys all the important principles of mass transfer namely:

Turbulence in the koi pond vortex chambers (note I refer to the biological NOT mechanical chambers) creating high concentration differences required for good mass transfer.

Surface area in the vortex koi pond filter chambers is high for mass transfer

All components including the much needed oxygen come together at an efficient interface in these koi pond filters

Some people refer to uv pond filters. You should note that the term uv pond filters or uv filters for water gardens refers to items NOT designed to purify water but to remove the pea soup appearance of pond water. uv filters for water gardens are covered in a different web site - see the ultra violet links. Pond filters with uv are however commonplace and can save a lot of hassle since it is normally simpler to install combined pond filters with uv than the two seperate components.

Algae in koi fish ponds, koi pond algae control: please review our web pages on ultra violet light

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copyright: 2002, this website and many others to do with water gardening and use of water in the home was created by Tony Roocroft who lives in Johannesburg South Africa