A COMPARATIVE INTRODUCTION

Imagine a river…..

There is a constant inflow of fresh water from far away where there is plenty of rain. There are waterfalls tumbling over rocks introducing oxygen into the water. The input = fresh (free of toxic substances) water with a constant input of oxygen.

There are a host of life forms growing in the water from microscopic organisms to macro organisms to larger animals such as fish. There is an abundance of food and although the animal life forms remove oxygen whilst breathing this is continually replaced. Further any excretion of ammonia (for example) is diluted by the influx of fresh water as well as bacterial activity found on the floor and sides of the river. There are a limited number of fish relative to the amount of fresh water.

Now imagine you have cut a piece of this river out and placed this bit of paradise in your garden.

 
Consequences of your Actions

You have a pond, you add Koi. The life forms in the pond will need oxygen immediately. This in turn leads to metabolic activity. Food will have to be supplied and the by-product of metabolism & food is ammonia. Ammonia is toxic in minute quantities and will have to be removed as soon as possible.

You remove impurities and add oxygen by moving the water through pipes to a filtration/bioconversion system and back to the pond.