Clear water is usually the primary goal of any water gardener short of the first lily blooms. In a new pond, however, the water is seldom clear for very long. This can be rectified easily if the pond is of the correct depth, has a good filtration system, and correctly chosen plants and wildlife are stocked in sufficient numbers. The only ingredient left to clear the new pond water is patience.
The worst thing to do is change the water. Replacing the water will only delay the developing balance of the new pond’s ecosystem. There are algaecides on the market and even dyes to artificially color the water, but these are only temporary solutions to a problem only nature can correct. When fertilizing the lawn, take care not to contaminate the pond. Any new nutrients introduced to the system will only prolong the life of the algae or even start an algae bloom. Algaecides are of dubious value as they kill the algae all at once instead of the slow natural death rate that the pond ecosystem can handle. When this happens, the microbial population of the pond begins a massive degradation of the algae and in so doing uses all of the oxygen in the pond. This will weaken the animal life in the pond and possibly result in a fish kill.
What is turning the pond green are innumerable single celled algae. These are present in all water and will create a bloom in any water left in the sun undisturbed. The long filamentous algae that grow on the bottom and sides of the pond are not responsible for the discoloration of the pond. These filamentous algae are actually good for the pond and aid in concealing the liners, shelves, pots, and bricks used to prop up some pots.
In time the balance of the pond will shift away from the green algae, and the plants will cover most of the pond’s surface denying light to the algae. The oxygenators and other plants will eventually outcompete the algae for the available CO 2 and soluble nutrients. Sometimes the pond will suddenly clear overnight as the algae succumb and sink to the bottom.
Occasionally throughout the pond’s life, this algal bloom may reoccur for a short time. It may happen in the spring when the water in the pond has turned over (undergone a temperature inversion), the temperature of the water is increasing, the nutrient levels are up, and the plants are still dormant. Algal blooms of short duration are to be expected.
Pumps should be pulled from the pond and cleaned regularly. The filters may need weekly cleaning. The interval will depend on your particular pond’s ecology. The filter should be checked weekly, and the pump inspected at these times and records kept to build a history of your pond. This is the best way to know what your pond needs and when.
Liners should last without problem for the time specified by the manufacturer if they are properly installed and care is taken not to puncture them while walking in the pond to service the plants, fish, and circulation system.
Edging, if well designed and constructed, should never need servicing. If the liner is installed and does not allow water in under the edging materials, and the ground underneath is firm, the stone or brick pond edging should give no trouble. If the pond is edged by lawn edging or has no edge, the main concern is to avoid contaminating the pond with lawn fertilizers and pesticides.
As the leaves and flowers of the aquatic plants die they should be removed. Watch the root balls and leaves for damage by fish and insects. Once a year lotus will need repotting in the south portion of Texas; in the north, every 2 years.
Fish should be watched for infections of fungi and other parasites. If any die, remove them as soon as they are found. If any seem particularly intent on eating your plants, decide which you are most fond of and take appropriate action.
In winter the pond slowly shuts down. Any tropical species should be stored in the proper manner for each plant. The fish have greatly slowed their intake of food and their actions in the pond. They will need feeding only occasionally in the south and not at all in the north where the ponds freeze over for the winter. In the event that the pond should freeze over, a hole in the ice must be maintained for the survival of the fish. If the hole is not maintained there can be little air/water gas exchange and the fish will die as they continue to respire and use all of the oxygen dissolved in the water of an ice covered pond. A hole in the ice can be maintained using any of the commercially available electric ice melting devices specifically designed for use in pond situations. Never use any device not manufactured specifically for that purpose. Never hit the ice with anything to break it open. The force from the blow will reverberate as shock waves in the pond and kill the fish. This is one of the major causes of winter death of fish in home ponds.
Another source of problems for the plants in winter is the accumulation of fallen leaves that may blow into the pond with every gust of wind. These and any dead fish should be removed immediately.
You do not need to run pumps throughout the winter as the fish need very little aeration and the algae are not growing at this time. However, the algae will have a spring bloom usually as soon as temperatures rise enough to heat the pond to any depth. At this time the pump and filtration system must resume its operation.