Koi Pond Management – Overview

As an introduction to the new series called Total Pond Management, Ben Helm takes us through an overview of a behind-the-scenes exploration or the many natural processes and phenomena that help to maintain a healthy pond environment.

Ponds can be incredibly dynamic environments. Through this series, we will be looking at how a whole collection of different natural processes combine to create a pond’s characteristics. Rather than taking ‘behind-the-scenes’ to mean the roles performed by filters, pumps, pond design and nutrition in a pond, to gain a greater understanding of how a pond ‘works’ we will be looking at the chemical and biological processes whose work can be enhanced by pond hardware. In fact, where appropriate, both natural (clay ponds) and artificial (filter, recirculating ponds) will be used to illustrate the effects of each of the fundamental processes can have on a water body.

Why go into such detail? For the concept of Total Pond Management to be useful to us on a daily basis, we need to appreciate the number of different processes that occur beneath the surface of the water and understand how they interrelate with each other to produce our own pond’s characteristics.

For example, no two pond environments will ever be the same, even if they are constructed identically and maintained with identical hardware. The same is true of ‘natural’ clay ponds that have been constructed within a week of each other, having the same dimensions and source water. This phenomenon is recognised by us all, but can be explained by the array of different (and often hidden) processes that occur with our ponds. Total pond management aims to ask the questions why apparently identical ponds may have different characteristics and explain the processes involved in giving each pond its own unique signature.

Better Management: If you can measure it, you can manage it.

The better informed we are of how a pond ecosystem works and the more parameters we can measure (and understand how they interrelate and affect each other) the better we can manage our water quality. The objective of total pond management is not to make all ponds identical, but to help to create a stable pond in which koi will thrive. It will also help us to understand why koi appear to prefer certain environments over others and what, if possible, we can do to close the gaps we may have in our own pond systems.

Total pond management also looks at the implications of our actions with respect to a pond’s stability, explaining the reasons behind such observations and what we can do accordingly. A pond’s stability (which should be our goal) within prescribed limits is controlled by a series of inputs, processes and outputs and throughout this series, we will be looking at the stages involved in maintaining a pond’s stability in particular detail.

For example, the act of feeding koi will start a chain reaction all of which can affect a pond’s stability. Yet perhaps we have only considered feeding as far as satisfying a koi’s appetite and the burden it may put on filtration. As we will see, the act of feeding (and the addition of food itself) causes a whole chain of events to occur besides those we are very familiar with, all of which may challenge the quality and stability of our pond.

Although the series will be looking at 7 different processes or phenomena that can shape a pond’s characteristics, it is also important that we do not consider each process independently of the others. Each one will interrelate with the next and should be considered as working in partnership with the other areas. In brief, the 7 processes that this series will be looking at in the context of ‘Total Pond Management’ will be:

1. Respiration, gas exchange and aeration.

The most influential organisms in a pond are aerobic, requiring a steady supply of oxygen. Besides koi, this includes plant life, and the vast majority of micro-organisms that become established in their own niche. If we supply additional aeration to a pond, besides having a direct beneficial effect on koi health, it will also boost the performance and health of the pond. Why? How is the performance of aerobic organisms enhanced when we provide them with more oxygen? Also, if mud ponds do not routinely receive additional aeration, why are they considered to offer koi the best growing conditions?

Respiration is a term often used to describe the gas exchange process when in fact it also represents a biochemical process with specific inputs and outputs. How does respiration affect a pond’s stability? When is respiration likely to be at its greatest and what does this mean for the way we manage our ponds? How does the respiration of other organisms affect both the pond environment and then koi health (either directly or indirectly)?

2. Osmosis and Diffusion

These two processes are essential for the health and well being of all organisms (however large or small) in a pond. Diffusion and osmosis are similar natural processes that involve the movement of solutes (substances dissolved in water) such as oxygen and carbon dioxide through to minerals and dissolved nutrients. Osmosis also involves the movement of water into and out of all organisms – a vital process for the health and well being of all aquatic organisms. By being aware of the roles that osmosis and diffusion play in the life of organisms that sustain our pond’s quality, we can also be aware of how we can influence (both positively and negatively) their functioning. Koi suffering from ulcers face tremendous osmotic challenges, and by being aware of this, we can manage the pond to the benefit of our koi. (But does that intervention have implications for other pond life?)

3. Digestion and excretion.

Wherever digestion takes place, there will be excretion. All koi and most bacteria require food from which they gain their nutrients and energy. Their excretion (in both quality and quantity) is determined by how efficiently the food is digested as well as by certain environmental conditions. The effects of excretion have a great potential to disrupt the stability of a pond, particularly if such rises happen rapidly. Furthermore, one man’s muck is another man’s brass and an increase in excreted products can cause a domino effect in the number of bacteria and micro-organisms which themselves demand other factors accordingly, all of which could upset the pond’s balance further.

4. Metabolism.

As all organisms in a pond are poikilothermic (ie they take their body temperature from the water) their rate of metabolism is governed by water temperature. What affect does this have on a pond’s water quality as the temperatures fluctuate through the seasons. If you choose to heat your pond over winter, then what effects does maintaining your kois’ metabolism at a higher rate have on other aspects of your pond? Is the relationship between temperature and metabolism a direct one or do other factors play their part also?

5. Photosynthesis.

% of life on earth relies directly or indirectly on photosynthesis. That is, the manufacture of sugars by plants, utilising chlorophyll, sunlight and carbon dioxide, leading to the release of oxygen. This process obviously has peripheral process associated with it, including the take-up of other nutrients from the water. Yet there is no mistaking the difference in the colour of water in a clay pond as opposed to a filter, recirculating koi pond. How does the environment supporting suspended algae (green water) differ from that of a crystal clear pond and what other factors are likely to differ between the two environments as a result? Are these differences really significant to the stability of the pond or the health, growth and colour of our koi?

6. Bacterial Activity.

Bacteria are the highly specialised recyclers of an environment, especially the aquatic environment. Working in very specialised niches, bacterial activity is at the heart of the breakdown of a myriad of compounds and by-products that would otherwise accumulate in pond water. We are all familiar with Nitrosomonas and Nitrobacter species of bacteria and their role in the nitrogen cycle, but this is merely the tip of the iceberg when considering the needs and roles of other bacteria in a healthy pond. What other bacteria live and work in a healthy pond and what are their requirements?

7. Cycling of nutrients and biological loading.

The series will conclude by looking at the role a number of nutrients play in a pond environment, how they cycle, taking on different guises in a pond and the processes involved in the cycling of nutrients. We are familiar with the nitrogen cycle, but there are other important nutrients that cycle throughout a pond in a similar way that exert and influence on our pond’s biology. Where do these nutrients come from and where do they go to? The clay pond is obviously minerally very rich compared to a clear pond, so what are the implications for koi health?

Even though these 7 areas are by no means exhaustive in their examination of the processes and phenomena that work ‘behind the scenes’ in maintaining a healthy pond, they each have a significant role to play, each of which is highly interrelated and subject to our actions in and around a koi pond. By taking a holistic view of pond management, we can better appreciate and manage the factors that combine to determine the quality of our pond’s water.

Kill blanketweed and string algae.