The revolution in pond systems started about a decade ago. This new approach has drastically lowered the maintenance needed for ponds, made them more affordable and owner-friendly while at the same time much more natural looking than any ponds before.

To help you understand how these systems work and to help you choose what type of pond would be best for your backyard let's go over some of the basics about ponds and filtering systems.

What's Being Filtered in a Pond?

A filter is a device for straining substances in suspension from a liquid or gas by passing the liquid or gas slowly through cloth, paper, sand, ceramic tile, charcoal or other porous media. Media is a substance that carries, collects or holds some other substance. Filtration media then is the sand, charcoal, ceramic tile itself. A filter is used to remove impurities from water.

What's being filtered in a pond (what scientific types call the "load") is the amount of impurities and nutrients that are in a pond at any given time. The load consists of fish waste, leaves, cut grass, tree bark, wind-blown dust, and all the other debris that can collect in a pond, sink to the bottom and decompose. The decomposed debris adds both nutrients and impurities to the pond. The amount depends on the size of the pond, the number and size of the fish, the surroundings and a number of other factors, so any filtration system must be designed to handle the load of that specific pond.

Pool Type Filter Systems

Traditionally ponds used filter systems similar to swimming pool filter systems. The purpose was to remove all impurities from the water. Pool filters can be expensive to purchase and to operate. They are housed in a separate enclosure that must be built and connected to the pond by underground pipes. Because the pumps are external, they tend to be loud, so some sort of silencing has to be added to the enclosure.

Ultra violet lights can enhance the filtration process, but they are expensive, need extra maintenance, and require a restricted water flow to do their work. Not only the impurities but also beneficial live organisms are destroyed.

Pool filtration systems do work and can keep a pond very clean, but they fight the ecosystem rather than using it the way it works in nature.

Biological Filters

Since about ten years ago biological filters have become a viable alternative to the traditional pool type filter systems.

Where a traditional filter system simply kills all the organisms it can, the action of biological filters is a bit different. Take the handling of algae, for example. Rather than killing the algae with chemicals, biological filters use natural activity to remove certain nutrients from the water. This in turn starves the algae and prevents its growth.

A biological filtration system uses the natural cycles of plant, animal (fish) and bacterial action to create a stable ecosystem in the miniature environment of the pond. Because it is natural, plants and fish thrive, and the pond becomes a stopping place for birds, dragonflies, and other beautiful visitors. The pond becomes a piece of nature right in your own back yard.

In the next article, I'll go into more detail on biological filtration and the ecosystem that it uses to keep a pond crystal clear and healthy.

California Waterscapes (now a division of Pacific Outdoor Living) has been installing beautiful and successful water features for several years. With thousands of ponds and waterfalls installed, we are glad to have made a contribution to improving the value and ambience of so many homes.