Maintaining pond water quality is important for the man-made pond as much as for natural ponds. An unbalanced pond chemistry throws off healthy plant and animal life, sending the pond into a deadly cycle. The result is a smelly and unsightly mess, something you don't want in your yard or near your home. Water quality impacts more than human health. Since pond water is one common water source in the over all water resource scheme.
A decorative pond, often filled with colorful fish, is an asset to many homes. But keeping the pond water sparkling clear can be challenging. Many factors can influence pond water quality, turning water brown, green, milky foamy, or smelly. Hidden hazards for aquatic life include dissolved gases and heavy metal ions. There are as many solutions as there are pond water quality problems.
Ponds filled with drinking water must be de-chlorinated before fish and other aquatic life are introduced. De-chlorination is usually accomplished by adding chemicals to pond water which combine with chlorine ions to form solid compounds, which are then filtered out of the pond water. Sulfite salts are the active ingredient in many pond water de-chlorinators.
Similarly, chemicals that bond with heavy metal ions to form solids that precipitate in filterable form can improve pond water quality. Such "de-toxifying" products are sold by aquarium and pond supply stores. Some products combine de-chlorinating chemicals with a number of other chemicals that bond with the heavy metals most often found in tap water: lead, cadmium, chromium, zinc, and others. Note that heavy metals are seldom present in tap water in concentrations high enough to concern humans who drink it; but metal concentrations can build up in ponds as water evaporates and is replenished.
Proper aeration is important to pond water quality. Falling water from input pipes or more natural-looking waterfalls mixes oxygen with water. Oxygen is essential to aquatic life, and helps reduce buildup of ammonia and nitrites formed from decomposing organic matter.
Ammonia and nitrites will accumulate in pond water none the less. Levels of these organic compounds should be tested regularly, and chemicals which neutralize them should be added when levels get too high.
Sparkling clear water is the aesthetic goal of every pond owner. The color of murky water generally indicates what problem must be addressed.
Milky-white water usually indicates a bacterial bloom. A coagulating chemical, such as AccuClear, forces bacteria and other solid contaminants to clump together and fall to the bottom of the pond, where filters can trap them.
Brown water indicates floating dirt and organic debris, such as decomposing leaves. Organic debris can release tannins, chemicals used to tan leather. Clearing up brown water is work. The pond’s filter must be cleaned thoroughly. A coagulant should be added to precipitate suspended particles. Finally, the pond water should be vacuum-filtered manually.
Green water is caused by algae, microscopic plants that can bloom suddenly and profusely. Just as suddenly, algae blooms die off naturally, leaving water clear again, but many pond owners don't want this green/clear cycle. Pond owners can minimize algae blooms by shading ponds with trees, awnings, or floating plants such as water hyacinth, water lettuce, or water lilies. Floating or submerged plants compete with algae for nutrients, starving algae out. Bales of barley straw have been touted as remedies for algae bloom, but this method is not very effective against the species of algae that color water green.
The ultimate weapon against water-coloring algae is ultraviolet light. Exposing water to UV light as it runs to the pond will sterilize algae, preventing it from breeding. UV light water clarifiers should be installed by trained professionals for safety and operating efficiency. Their cost can range from a couple of hundred to over a thousand dollars, depending on the water flow to be treated and maintenance-saving features selected.
Foam occasionally appears on pond surfaces. If foam is seen at dusk or dawn during fish mating season, it’s usually fish sperm and of no concern. Ponds also trap proteins and other organic compounds in bubbles to form foam, particularly at the bases of waterfalls and other turbulent inputs. This natural process helps prevent formation of ammonia and nitrites. These natural types of foam can simply be skimmed off pond water.
Foam can also be a sign of stress in pond fish. Fish exude protective slime when they are stressed, which is a protein that can increase foam production. Regular testing and chemical control of ammonia and nitrite levels can relieve stress and reduce this source of foam.
String algae is different from free-floating algae that colors water green, and must be treated differently. String algae takes the form of lacey nets which cling to rocks and plants; indeed, string algae usually gets into a pond with the introduction of new plants. Algaecides should not be used to get rid of string algae; they may kill all plants and harm fish.
Controlling string algae is a two-step process. First, the existing string algae can be killed by a product called AlgaeFix. The string algae will die and turn black. Hose it off of surfaces and it will sink to the bottom of the pond, from which it can be vacuumed. To prevent resurgence of string algae, bales of barley straw can be placed where pond water flows. Barley straw contains enzymes and beneficial bacteria which inhibit string algae reproduction. One barley straw bale per 1,000 gallons of pond water will do the job for 6 to 8 months, although it may take a couple of weeks to show results.
Do not confuse string algae with the jelly-like slime algae that grows on the sides on ponds. The latter is beneficial; fish eat it, and it provides a home for beneficial bacteria.
Maintaining pond water quality can be a lot of work. But the beauty of a healthy pond, the tranquilizing sound of running water, and the soothing languor of fish are well worth the effort.
