We have, in the past, talked about how important organic waste management is in our ponds.
It is wholly unrealistic to think that an outdoor seasonal KOI pond can be run without addressing eutrophic tendencies inherent in such an environment. Just recently, I was discussing the need for lush biofilm cultivation as the most humane approach for koi having to live through a new pond syndrome period, and at the heart of that concept exists the very nature of a koi pond- as a closed system subject to continual organic processing.

Once the correct biofilm is established, our job as koi keepers is to manage macro organic accumulation.
The primary way to address this reality and keep it from becoming a threat to koi health is through pond design. Specifically, synergistic pond design. The dimensions, shape and surface area of the constructed pond is the starting place for waste management. Unfortunately this planning is over looked in 90% of all the ponds built in America and results in a ‘losing battle’ for many a pond keeper trying to stay ahead of disease, green water and chronic skin problems in their fish.

The pond should be deep and the floors should be sloped or terraced so that mulm will not build in corners or crevices on the pond floor. The edging along the pond should always be mortared or sealed so that material does not build under and behind rocks or ornaments. The location of drains is also key- as are the number of drains based in pond volume and floor dimensions. The drain lines can be either too small or too large, so some research should be put into the details of drain function and its link to required pond turnover through the filters. If a drains lines are too large and long, you will turn your drain line into a settlement chamber! This is a major problem as biofilm tends to set up there naturally and many problems can occur then that the owner will be completely unaware of! If left as a runaway problem, and if attached to a closed or pressurized filter system, this can be a chronic disease causing dynamic that is never identified by the owner.

The next logical level and sequential next step in organic waste management is the prefilter. This is an area that has been improved greatly since the days of sand filters, gravel beds, baffle screens and pleated cartridge filters. Examples are- The sump for collecting ‘heavy waste’, the vortex for collecting and separating finer organic material, the ANSWER, along with a host of other similar ideas for blocking ( self cleaning) finer-still-organics from entering the bio-rector areas of the filter. These systems of course, are only as good as the maintenance schedule so state of the art ponds tend to have auto systems of one type or another to deal with this. From something as simple as a constant overflow to waste within the sump, to air driven compressors, these units provide a frequent to continual driven maintenance remedy to waste build up once it has been trapped in a zone or separated from circulation.

And finally we have the biofilm, a living system subject to eutrophication itself, this population of microbes is expert at dealing with the ‘unseen’ component of organic waste. And this is how the advanced hobbyist should see this function- not as a zone for visible waste break down, but rather a zone that should remain free from 99% of what can be seen so that it can be free to manage the REALITY of a koi pond byproduct- molecules and chains of proteins, lipids and DOCs of all descriptions. This is the ultimate natural conditioning of water. And this is why technology in the form of flocculants, foam fractionators ( in terms of real results) and ozone units miss their mark in koi ponds.

So summarize, a koi pond is not an aquarium. It is an environment that is constantly being pulled towards organic excess. It would unrealistic and counter productive to believe it is possible or wise to bring the organic content to zero ( just as we really can’t bring inorganic ammonia levels to true zero). So we need to approach this with a management mentality, that is, we want natural systems for coping with organic material so that water is conditioned for koi- ‘a creature of the mud’. And we want artificial or man made systems to protect a closed body of water from excess ‘aging’ due to organic build up which ultimately leads to a system that will crash.

-JR