Images on this page courtesy of Tranquil Pond Products
With the aid of biological filtration, your water feature becomes its own self-reliant ecosystem like that of any pond found in nature. It is just a matter of the food chain, starting at the bottom with bacteria. Plants in the pond absorb CO2 and other impurities from the fish and other animals, while at the same time providing oxygen for them. Of course, the fish in your pond naturally fertilize the aquatic plants with their waste. This system that forms can almost indefinitely prevent you from having water problems. When a pond is ruined this way, in terms of water quality, it can mean a tragic sudden death for your prized fish.
Every water feature has a water flow made up of an intake and an outlet, like that of a complete circuit that is flowing through itself. In most conventional circumstances, there is a skimmer box at one end of the pond and a waterfall at the other end, which is more elevated than the skimmer. These two units are connected via a length of flexible PVC pipe, which is concealed in the ground around the water feature.
One of the two main types of filtration takes place in each of these ends. Inside the skimmer, where the pump takes in water to move, is where mechanical filtration takes place. Biological filtration is achieved by the water flowing through bio filter media filling the inside of the waterfall box, as it then falls back into the pond. Both mechanical and biological filtration should be used together, along with the pond’s ecosystem of plants and fish, to create a naturally perfect pond. Being free of problems, there is usually no need to treat the water with additives or other chemicals.
Actual, physical filtering of the water is done within the skimmer, where a plastic net blocks larger debris such as twigs and fallen leaves. Then, there is a fibrous plastic mat that more finely separates and contains smaller particles from the water as it is drawn to the pump. The skimmer can be modified to concentrate more on skimming the surface for such debris as floating leaves, or to focus more on skimming debris from the bottom of the pond. That’s mechanical filtration.
At the other end, the biological filter lets water pass through a large surface area of beneficial bacteria at a rapid rate. A perfect example of this would be: lava rock inside the waterfall chamber that the water runs through, right before it is seen pouring out of this box (in the form of a waterfall). Specifically, this is aerobic bacteria at work here, while anaerobic bacteria play just as important of a role.
A third type of filtration exists: the sterilizing filter. It is comprised of a UV light that emits a high-output ultraviolet spectrum. This is, without a doubt, extremely effective for the type of algae problem seen as “green water”. When water is passed over the light, it alters the DNA of single-celled organisms such as bacteria and algae, ultimately killing them and fixing the appearance of the water. This tends to be more common in water features that do not have such an established ecosystem. An example could be a large stone well with a fountain, housing some koi but no plants—per the owner. The water is an unsightly green. A solution to offer the homeowner would be the installation of a UV sterilizer in the plumbing, somewhere along the line between the pump and the return. This does not have to be near the pond; it is actually set up inside an adjacent barn or garage area. The UV light is also be a proper solution for control of parasites if your fish are so diagnosed, but chances are you would be using one for algae bloom before this other type of problem. Although normally a diagnostic and not installed in a new pond, there are no cons at all to this type of UV sterilization, as it is a “set in and forget it” method.
The Basics and Types of Water Features
Types of Aquatic Plants for Your Feature
Keeping Fish in Your Water Feature
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