Why Does My Aquarium Have So Much Algae?

Does your aquarium receive direct sunlight or artificial light for more than eight hours a day?

Are you giving your fish more food than they can eat?

Do you change the water in the aquarium regularly?

Do not place the tank where there is direct sunlight for even part of the day. Sunlight can, and will, promote algae growth. When using artificial light, make sure it is not stronger than necessary and is not on more than about eight to ten hours each day. Use a timer to turn the lights on and off each day.

The majority of owners overfeed their fish, which increases the phosphate levels in the water. Feed small portions and watch the fish eat. If all the food is not eaten within five minutes, you are feeding too much. Always remove any uneaten food promptly.

The single most important way to avoid algae is to perform regular water changes. Change 10 to 15 percent of your aquarium water every week to keep nutrients in the water low. This will remove the nitrate that accumulates in aquariums, one of the main fertilizers for plants.

Test your water source. If it is high in phosphate, you should consider using phosphate removing chemicals available at your aquarium store, or find another water source, such as filtered water. Also, it is wise to test for nitrate, as some water sources have elevated nitrate levels. It does not do much good to change the water if you are adding nutrients back in the aquarium with tap water.