One of the biggest problems faced by people who maintain aquatic environments is algae. Algae control for aquariums is quite different from methods used for garden ponds, but regardless of the environment, controlling algae depends on reducing the amount of sunlight and the level of nutrients in the water.
What is Algae?
You can think of algae as the microscopic weeds of aquatic environments. In the presence of strong sunlight and excess nutrients, algae builds up to form an unsightly growth on the surface of the water and on underwater plants, rocks and ornaments. It can also give the water a green, pea soup-like appearance.
Aquarium Algae Removal
The best algae control for aquariums is cleanliness. Use an algae scrubbing pad to remove algae from the sides of your aquarium. You can find algae scrubbers at any aquarium or pet supply store. Some are attached to long handles that make reaching the bottom of the glass easier. Beware of scrubbers attached to thin wooden dowels. Once saturated with water, thin wooden handles break easily when you apply pressure.
The best time to scrub off the algae is when you make a partial water change. Scrub the sides of the aquarium while the water level is low.
Algae also builds up on the substrate in the bottom of the aquarium. Remove the top layer of substrate and replace it with fresh material. Clean up the old substrate by laying it out in a thin layer to dry. When the algae dies, rinse the substrate and return it to the aquarium next time you clean it out.
If algae builds up quickly in your aquarium, make sure it isn’t sitting in direct sunlight.
Control of Algae in Ponds
Two factors that lead to an algae buildup in garden ponds are an excess of nutrients and strong sunlight. Fertilize the plants in the pond only when necessary, and use a slow-release fertilizer. Fish provide additional fertilizer in the form of droppings. Overfeeding fish results in an abundance of droppings and nutrient-rich water. Don’t overstock your water garden with fish and feed them responsibly to maintain a balance of nutrients in the pond.
Strong sunlight encourages the growth of algae. Surface plants, such as water lilies, shade the water. Consider covering as much as 50 percent of the surface of the water with water lilies. The fish will enjoy the shade and hiding places that the lilies provide, and they will also act as a biological filter to help keep the water clean.
A good rule of thumb for stocking your pond is to add six 4- to 6-inch fish and one large water lily for each square yard of water surface.
Using herbicides in the garden pond should be a last resort. Herbicides can kill your aquatic plants and harm the fish in your pond. If you absolutely need to use one, go with an EPA-approved herbicide developed specifically for use in garden ponds and follow the label instructions carefully.