What are the Chemicals for Garden Ponds?

Chemicals assist in the initial setup of a garden pond as well as its year-round maintenance. Changing seasons and temperatures may also dictate the use of these substances, as do the presence--or absence--of aquatic plants. Because no two ponds are exactly alike, suitable brands vary, as do frequencies of application. The landscaper who keeps a garden pond stocked with fish is sure to appreciate the availability of chemicals that keep the water clear and safe, while not harming any aquatic animals.


Control algae growth in garden ponds primarily through mechanical filtration and the introduction of aquatic plants. When these methods prove insufficient--or in the time that it takes for pond flora to establish itself--chemicals known as algaecides effectively treat algae problems. Verify that any product you choose works on all forms of algae for a broad spectrum treatment or on a specific kind, such as string or hair algae, for spot or seasonal bloom treatments. Opt for a product that does not harm the aquatic life of the pond; for bodies of water that do not contain desirable plants, you can use harsher chemicals.


Pond herbicides kill aquatic plant life. Because these chemicals generally do not differentiate between the desired plants and those the water landscaper considers weeds, an application likely leads to the destruction of all plants. Remove desired aquatic plants from the pond before adding the herbicide. Check the duration of the substance’s effectiveness, and re-introduce the plants after the herbicide dissipates. For ponds with fish, choose herbicides that are fish-safe. A good example is glyphosate, which manufacturers use in formulas for common land weed killers but also specialized pond plant eliminators that do not harm fish.


Municipal water contains chlorine as well as chloramines. These chemicals are normally not toxic to humans and ensure drinkable water quality. They are unsafe for fish and aquatic plants, which makes it necessary to de-chlorinate pond water before introducing plants and animals. It is possible to remove chlorine merely by letting water stand for 24 to 36 hours and allowing the substance to dissolve into the air. This does not work for chloramines. A dechlorinator removes chlorine as well as chloramines quickly. Use this pond chemical not only during the initial pond setup and subsequent water changes, but also remember to add it to any water you add during the season to make up for evaporation.

Keywords: control algae, kill aquatic plants, remove chlorine, pond chemical types

About this Author

Based in the Los Angeles area, Sylvia Cochran is a seasoned freelance writer focusing on home and garden, travel and parenting articles. Her work has appeared in "Families Online Magazine" and assorted print and Internet publications.