Controlling Green Water Algae
Author: Terry Newhaven
Green water and fish ponds unfortunately are fairly synonymous. Even non-pond owners negatively associate Fish Ponds with bright green water or pea soup water. It is something that every pond owner has had to deal with at some point, and it is a natural, even healthy occurrence in outdoor ponds. Fortunately, there are steps you can take to ensure this malady does not befall your pond.
Green water or pea soup water is common way to describe the outbreak of planktonic algae in a pond. Planktonic Algae is a very simple organism. It requires has two very basic needs for survival, food and light. Unless you block out the sun, or completely cover the pond in light-blocking floating pond plants, every Fish Pond has sufficient light to grow algae. Keeping nutrient levels low enough to prevent algae is an almost impossible task. Nutrients are found in the water used to fill your pond, unless you spend a fortune to use pure reverse osmosis water. Nutrients are also found in fish food, in the soil and rockwork that may runoff into your pond during rain events, and in leaves and other natural waste that may fall into your Koi Pond.
A much better approach when trying to control green water algae is to attempt a natural, balanced eco-system. In a balanced system, the nutrients created by you and your fish are used naturally by the plant life in the pond. In this situation, there is no surplus of nutrients, and as such, will not be available to nuisance algae. The common downfall to this situation is overstocking and overfeeding. Either of these can spell disaster for your algae growth. Even though extra filtration may create a safe living environment for the extra fish, there is nowhere for the extra nutrients to go.
There are also several methods of artificially controlling planktonic algae, the most effective of which is the Ultraviolet or U.V. Sterilizer. The Sterilizer will actually neutralize the algae that flows through it, effectively controlling the population. Although that may mask the problem, it will not eliminate it, creating a potential outbreak situation if the equipment ceases proper operation.
There are also many commercially available algae-destroying products. There are a wide range of these products, from the inexpensive to the high end, all with varying results. If utilizing such algaecides, be sure to carefully read the label. Some of these contain copper, and will kill invertebrates and plants, and some will even kill fish! There are some that will help with the biological filter, eliminating the nutrient source of the algae. These can be effectively added to your maintenance regimen with good results. Although sometimes cost prohibitive, nutrient-eliminating algaecides will not harm your biological filter or your plant life, and are the safest products available for use.
The war on green water is a battle that can be won. Even though the nutrient source cannot be eliminated completely, it can be limited to a workable size. With plenty of plant life, a good U.V. Sterilizer, and appropriately sized filtration, crystal-clear pond water can become a reality. There are even some good products to help you along the way, if you know what to look for.