There are several types of algae that can occur in a pond. One type causes the water to be green in color, one type produces string,hair-like algae and the other type produces a “blanket” effect. A pond can have one type or a combination of the three types.
There are several methods available to control algae.The “oldest” method is to have at least 70% of the the pond’s surface covered with floating plants. Water hyacinths and water lettuce work very well. They serve to block sunlight and absorb excess nitrates that are in the pond. Sunlight and nitrates(fertilizer) are two primary ingredients needed by the algae in order for it to grow rapidly. Another method for algae control is to use chemicals. Algaefix is a chemical product that is fish safe and plant safe. Care should be taken to follow the directions printed on the label. Adding more than the specified amount could adversely affect the fish population. A natural product called “barley” straw extract is an additive that can be used to deter algae growth. Natural products usually take longer to produce the desired results.
A very popular device used to control green water is an ultraviolet sterilizer. The size of the pond or water feature determines the size of the sterilizer needed. Proper water flow through the sterilizer is imperative to remove the “green” water. If the water flows too rapidly, the algae will not stay in contact with the sterilizer long enough to be destroyed. The sterilizer is primarily used to remove green water; however, spores released by string algae will also be destroyed as they move through the sterilizer. Ultraviolet bulbs gradually lose their strength as time goes on. Manufacturers recommend bulb replacement each year to assure maximum performance of the sterilizer.
Don’t despair, help is on the way!!