How To Prevent and Resolve Algae Problems In Your Water Garden
Balancing Your Pond For Clear Water
Remember that a normal, healthy pond will have clear water but will also have a layer of fuzzy algae growing on everything in the pond.† This stringy, filamentous algae can grow out of control, however.
Three Key SolutionsÖ
∑ First, it is best to do an annual drain and clean on your pond if the conditions are really serious, particularly in the spring when the algae blooms are worse.
∑ Second, set up the following combination of plants and fish in your pond to keep your water clear and to prevent the algae from returning.
∑ Third, add a good biological filter to your water garden for clear water quality and ease of maintenance.† For persistent green water problems, consider adding an Ultraviolet Clarifier.
Every Water Garden NeedsÖ
Water Lilies to shade and cool the pond, reduce evaporation, and protect your fish.
You Need one 2 or 4 gallon lily for every two square yards of surface water.†
You should have 50 to 75% of your surface area covered by aquatic plants to block sunlight.† Water lilies provide the best shade, yet other plant options are water hyacinth and shellflower, water clover or celery, parrots feather, snowflake, sensitive plant, and water poppy, etc.
Goldfish to eat stringy algae and mosquito larvae.
You Need eight inches of fish for every one square yard of surface water.
That means 2 four-inch size fish or 1 eight-inch size fish.† Overpopulation of fish is a common cause of algae problems as the fish waste feeds algae, and can also result in fish stress and disease.† Having an excellent external filtration system will allow you to carry a heavier fish load and is mandatory in Koi ponds.
Scavengers such as bullfrog tadpoles and Japanese Trapdoor Snails eat algae and debris.
You Need two to three scavengers for every one square yard of surface water.
Jap Trap snails are water snails and will not crawl out of the water to eat your garden.† Bullfrog tadpoles will likely turn to frogs this season, and will then be insect eaters and no longer scavengers.† Frogs may leave your pond, or may stay.† They are vulnerable to predators, but are predators themselves when they grow large.† They will eat baby fish.
Filtering Plants take the nitrogen out of the water and starve the algae.
You Need for every one square yard of surface water:† One pot of filter grass, celery or mint OR One Water Hyacinth or Shellflower.
Use hyacinth and shellflower ONLY in ponds with some shade protection as they can burn in our southwestern sun.† (No more than 6 or 7 hours of direct sunlight).† If you have everything else in your pond but leave out the filtering plants, you will have an algae problem.
To Figure Square Yardage:† Multiply average pond length by average pond width and divide by 9.
There are TWO basic categories of algae:† Pea soup Green Water is fixed by the above balance of plants and fish and ultraviolet clarifiers.† If you have Stringy Algae growing out of control, add tadpoles and stop feeding your fish for 1-2 weeks to get them eat the algae but DO NOT DO THIS IF YOU HAVE KOI! (They will eat your plants!)
ADDING A GOOD FILTER SYSTEM WILL ONLY HELP!