Algae are plants that are undesirable in any aquarium. Once algae grow in an aquarium, they will compete with the other inhabitants of the aquarium for nutrients and other resources needed for survival. That is why it is necessary to control algae in the aquariums. Algae can never be completely eliminated from an aquarium, but by using certain preventive measures, the amount of algae can quite certainly be kept to a minimum limit.

First, let us see the factors that promote the growth of algae.

1.Sunlight ? Just like for any other plant life, sunlight is absolutely essential for the growth of algae too. Though sunlight looks very good for the water of the aquarium, the same sunlight can cause algae to grow, which could be hazardous to the other living organisms. Not just direct sunlight, but any form of artificial aquarium light too would promote algal growth if it is kept on continuously for more than 10 hours per day.

2.Nutrient levels ? Algae will grow faster if there is an overabundance of nutrients in your aquarium. All plants require nitrates, phosphates and silicates for their better growth. When you introduce nutrients into the aquarium, the levels of these nutrients might go higher, which would facilitate algal growth.

3.Plant population ? Algae will grow faster in a tank if there are very few plants in the tank to compete with, because then they can get all the resources present in the tank.

Now that we know what the major factors promoting the growth of algae in aquatic tanks are, we can try to understand the methods that can be employed in order to check the growth of algae. The following are some algae control methods that can be employed even by amateur aquarium owners:-

1.There are some species of fish that eat algae. These fish are called as tank cleaner fishes. Some of the cheaply and popularly available tank cleaner fishes are the otos or dwarf suckermouth catfish, Siamese algae eater, bushy-nosed pleco, twig catfish and even the Japanese algae eating shrimp. You can introduce one of these fishes into the tank once it begins to show an algal infiltration. You can also include a hermit crab or a snail, since they feed on algae too.

2.Using a protein skimmer could be a very good option too. Protein skimmers are devices that remove the unwanted proteins from the tank environment. They will remove the dissolved organic compounds from the tank, which would otherwise promote the growth of algae. They bring the nutrient level down. Protein skimmers also reduce the concentration of carbon dioxide from the tank, which the algae, being plants, need for food preparation through photosynthesis.

3.Reduce the amount of actinic lighting in your aquarium setup. The actinic lighting is the blue light, and it helps to promote the growth of algae if used in excess. The ideal situation would be use 50% of actinic light mixed with 50% of white spectrum (daytime) light. Also, the light sources must be replaced periodically. All VHO (Very High Output) fluorescent lights need replacement after every eight months. Metal halide lamps will do with an annual replacement. It must also be remembered not to keep the artificial light source continuously on for more than 10 hours in a day.

4.Carbon dioxide is directly responsible for the growth of algae because, after all, they are plants. If your carbon dioxide filter has choked up, then there is a possibility that the level of carbon dioxide in the tank will be high. Using a pump in the aquarium to allow the water to circulate continuously is way of reducing on the amount of carbon dioxide in the tank. You can find out when the carbon dioxide level in the aquarium is going up by checking the alkalinity and pH value of the water within the tank. If these levels show an abnormal dip, then it is time to do something about increased carbon dioxide levels within the tank.