Why is there Algae in my aquarium?

Why is there Algae in my aquarium?

Why is there Algae in my aquarium?

Every aquarist encounters algae growth no matter how diligent you are about maintaining your aquarium. While its appearance is usually not welcome, algae is nature’s way of purifying water and removing pollutants, and it performs a valuable function in the aquarium. Some algae growth in a mature aquarium is normal, however, excessive algae can be a result of problems in water quality and maintenance habits. There are many causes for algae growth and just as many remedies. Understanding what causes algae growth is essential to preventing and controlling it.

How do nutrients affect Algae growth? 

Algae are aquatic plants in their most basic form, and like all plants, they need water, light, and nutrients to grow. In the aquarium, the primary nutrients are nitrate and phosphate, which typically come from fish waste but can also be present in tap water. A build-up can be caused by generous feeding, infrequent water changes or filter maintenance, overcrowding, using tap water that has high nutrient levels, or a combination of one or more of the above. If you start to see excessive algae growth, test your aquarium and tap water for nitrate and phosphate. Nitrate (NO3) should be below 10 ppm and phosphate (PO4) should be below 0.5 ppm.

To keep nitrate and phosphate levels in your aquarium low, avoid having too many fish, feed sparingly and perform regular water changes using nitrate and phosphate free water. To lower high nutrient levels and maintain optimum water quality, clean your filter regularly, use Aqueon Water Treatment Filter Pads, Kent Marine Nitrogen Sponge, Phosphate Sponge, Organic Adsorption Resin, Power-Phos or Reef Carbon. If your tap water has high nutrient levels, use reverse osmosis or deionized water with Aqueon Water Renewal, R/O Right or Liquid R/O Right when doing water changes.

Does excessive light cause Algae? 

Many people believe that the sole cause of nuisance algae is too much light. While it is certainly a contributing factor, algae are more common in aquariums with high nutrient levels, especially if there are no live plants. Avoid placing an aquarium where it will receive direct sunlight, even if it’s only for a few hours a day. Limit the number of hours the aquarium light is on, especially if you do not keep live plants. A maximum of 6 to 8 hours of light is sufficient in unplanted aquariums, while planted aquariums should receive 12 hours of high-quality light. Use a timer to provide a consistent photoperiod.

Quality of light is another contributing factor to algae growth. Fluorescent lamps weaken and undergo a change in spectrum called “color shift” as they get older. Since algae are more tolerant of marginal conditions, they tend to prosper under gradually deteriorating light whereas many aquarium plants do not. For the best results, fluorescent light bulbs should be changed every 10 to 12 months.

What are the types of Algae? 

  •     Brown Algae – most brown algae are a form of a diatom. They are often seen in newly set up aquariums and will usually die off on their own after the tank cycles. Diatoms use silicates to build their cell walls, so if your tap water contains high silicate levels, use reverse osmosis or deionized water when setting up your aquarium. Place Organic Adsorption Resin or Reef Carbon in your filter to remove nutrients and introduce Plecostomus, otocinclus or nerite snails to control brown algae in established aquariums.
  •     Green Algae – there are many types of green algae. Some are soft and easy to remove, while others are hard and can be more tenacious. They grow on the aquarium glass as well as decorations and even the gravel. Snails and algae eating fish help keep many forms of green algae in check. Maintain low nutrients and avoid overfeeding or overstocking your aquarium to prevent outbreaks.
  •     Blue-green Algae – these appear as a heavy, dark green film or “slime”. They are actually not algae, but rather a form of cyanobacteria. Left unchecked, they can suffocate live plants and even cause harm to fish. Blue-green algae can be removed by siphoning them from the aquarium, but they often quickly return. Several products are available for eliminating blue-green algae that are safe to use in fresh or saltwater aquariums.
  •     Filamentous Algae – there are many forms of filamentous algae, including hair, string, beard, black brush and thread algae. They are usually caused by a build-up of phosphate in the water and can be seen clinging to plants and other decorations. Longer forms can be removed by twirling them around a toothbrush. Siamese algae eaters, mollies, Redtail and rainbow sharks, goldfish and Amano shrimp are known to eat them. Shorter varieties can be eradicated using bristlenose and clown Plecostomus, otocinclus, nerite snails and dwarf freshwater shrimp. Plant leaves that become covered in filamentous algae should be trimmed out. To prevent filamentous algae outbreaks, feed sparingly, do frequent partial water changes using phosphate-free water and use Phosphate Sponge or Organic Adsorption Resin in your filter.
  •     Green Water Blooms – these suspended algae cause the water to turn bright green and very cloudy. Green water blooms are usually caused by high nitrate and phosphate levels, along with excessive light. Many hobbyists try to solve the problem by doing water changes, but the effects are temporary, and the problem quickly returns, often with a vengeance due to the addition of nutrients from tap water. Blacking out the aquarium for several days by covering it with a blanket and turning off the light can be effective, but this is detrimental to live plants and may result in ammonia and nitrite spikes when the bloom suddenly dies off. Diatom filters and UV sterilizers are the most effective cure. Chemical algaecides and coagulants also work, but again, sudden algae die-offs can spike ammonia and nitrite levels and some coagulants interfere with the fishes’ gills.
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