Natural Balance

By Jennifer Zuri

Current trends toward sustainable outdoor living provide opportunities for additional revenue streams to those in the landscape industry. Water features continue to be much sought-after landscape features, and ecosystem ponds answer the call for both outdoor living and sustainability trends. Working with Mother Nature — not against her — is the key to ensuring a naturally balanced ecosystem pond and an enjoyable water gardening experience. The recipe for a sustainable ecosystem pond is quite simple, and includes the five basic ingredients of circulation, filtration, rocks and gravel, fish, and plants.


Since an ecosystem pond is self-contained and is always recirculating its water, any well-conceived water garden starts with a good circulation system. Healthy circulation begins with a pump that possesses sufficient power to handle the required load, but not so much as to render it inefficient. The pump should be built with enough integrity to live up to a standard warranty of “one year of continuous use.”

A sturdy water-gardening pump provides aeration for the pond, which is important to the lives of the fish and plants — additional ingredients in our recipe for a healthy ecosystem pond. The pump should be housed in a skimmer, which is designed to skim debris from the surface of the pond into a basketlike net that can be taken out, dumped, and easily placed back in the skimmer.


Since we’re recirculating water and providing a home for fish, the next consideration is the filtration system. Recognize that there are two kinds of filtration going on in an ecosystem pond — mechanical and biological. Mechanical filtration physically impedes debris, while biological filtration helps to break down the debris and render it reusable in the ecosystem’s nitrogen cycle.

The main function of mechanical filtration, or skimmer, is to remove debris before it sinks to the bottom of the pond and decays. The skimmer also houses and hides the pump and plumbing from view, as opposed to being placed directly in the pond where they become an eyesore. The skimmer also won’t drain the pond if a possible leak occurs in either the plumbing or waterfalls.

There are two main types of skimmers — box skimmers and floating skimmers. Both types filter the water by removing floating debris and waste before it has had a chance to fall to the bottom of the pond. The box skimmer is the predominant type of skimmer on the market today due to its ease of maintenance. Box-style skimmers come with filter mats to aid in the removal of debris in a pond.

On the biological side of filtration, including aerobic bacteria into the recipe for an ecosystem pond will allow Mother Nature to efficiently break down biodegradable debris that finds its way to the bottom of the pond. The biological filter receives water that has already passed through the mechanical filter, or skimmer, typically placed on the opposite side of the pond. The water enters the biological filter via flexible pipe located near the base of the unit. The water then flows from the bottom to the top of the filter, traveling through filter media housed inside the unit. The filter media helps with the removal of fine- to medium-sized particles.

As the biological filter fills, it overflows across its waterfall lip, cascading down rocks that have been set to create a beautiful and preferably natural-looking waterfall. The waterfall creates additional aeration for the pond, assisting in the circulation and health of the water. If a slower, stream effect is preferred to a rough-and-tumble waterfall, simply sink the biological filter lower into the ground.

For any biological filtration to work, there literally needs to be billions of bacteria acting to purify the water. Bacteria prefer to anchor onto things, which is why surface area is so important. More surface area means more bacteria, and more bacteria means better biological filtration. Surface area is provided by filter media, rocks, and gravel.  A pond with gravel on the bottom will contain more surface area for bacteria, as opposed to a pond with exposed liner on the bottom.

Rocks and gravel

And so it follows that the third ingredient for the naturally balanced ecosystem pond recipe is rocks and gravel on the horizontal and vertical surfaces of the pond. The presence of rocks and gravel serves three valuable purposes. First, rocks hold the liner in place while protecting the rubber liner from the sun’s ultraviolet rays, which, if unimpeded, will cause it to deteriorate much faster than necessary. Second, rocks and gravel give aerobic bacteria a natural place to colonize. And third, rocks and gravel simply look natural in a way that a smooth surface, such as exposed liner or concrete, never could.


The fourth ingredient is fish, preferably koi or goldfish because they seem to be tailor-made for water gardens. They are colorful and make great pets, but there’s more than meets the eye here. Fish are scavengers and feed on various things in the pond including algae, mosquito larva and aquatic plants. After fish eat, they produce waste, which falls to the bottom of the pond and is then broken down and recycled into the pond’s nitrogen cycle and used as nutrition by the aquatic plants in the pond.

 Aquatic plants

The fifth and final ingredient for a sustainable ecosystem pond is aquatic plants. A wide variety of plants such as lilies, lotus, sweetflag and more add architectural interest to the water garden. But they’re much more than just aesthetically pleasing — they’re fish food and, since they also compete for pond nutrition; they also discourage algae. As a matter of fact, in order to minimize an algae bloom, there needs to be a sufficient amount of aquatic plants competing for the available nutrition, which effectively starves the growth of algae in the pond.

As with any successful recipe, these five key ingredients work synergistically, so eliminate any one at your own peril. The various elements in the naturally balanced ecosystem recipe are connected together in such a way that one is dependent on the other. Take one out and you’re asking for imbalance, and all the problems that come along with it.

Low-maintenance water features mean less stress for the homeowner in search of a relaxing outdoor living space. The beauty and sustainability of eco-friendly water features provide an identifiable difference for your business in tough economic times. You simply can’t go wrong with ecosystem ponds done right.

Jennifer Zuri is marketing communications manager for Aquascape, Inc., St. Charles, Ill. For more information, visit

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