Tap to Read ➤

What Causes Algal Growth and How to Control It?

Pragya T Jun 23, 2019
Too much of algae can turn the surface of fish tanks, ponds, and lakes green; causing a problem for the ecosystem. Read ahead to know causes the growth, and effective ways of preventing it.
Algae can be seen growing in freshwater as well as marine bodies. It is typically one of the few types of phytoplankton species, that grow on such water bodies. It can grow in concentration of hundreds to thousands of cells per milliliter, depending upon the severeness.
It is mostly seen in bright green color, but it can also take place in shades of yellow-brown or red, depending upon the types of algae species.
Though, most species of algae are not harmful to the ecosystem, however a specific type called Harmful Algal Bloom (HAB), can spread over a water surface quickly and pose harm to the plant or animal life.
HAB can block sunlight that is vital for organisms to live and some types of HABs can even release toxins in the water, such toxins are very harmful for humans and animals. Hence, it is very important to learn the measures to control algal growth.


Listed further, are the various factors that contribute to the algal growth.
• Algae to bloom and grow needs excessive amount of nutrients. Such nutrients are found in a water body due to a variety of sources, like most notable fish and animal waste, decaying vegetation, and run-off of the fertilizers from nearby pastures or farms. Such sources provide enough nitrogen and phosphorus required for the algae to grow.
Too much of sunlight is another cause of algal bloom. Ponds which receive direct sunlight are at a higher risk of suffering from algal problems. Hence, algal problems occur during summer time when the days are longest.
Low oxygen levels is the third major cause leading to algal bloom. Oxygen level can become depleted in water bodies which are stagnant. Algae can form and disappear, but when little oxygen is present in the water, then there will be new cycles of living algae forming.

Controlling Algae in Fish Tanks

To control the growth in aquarium or fish tank, make sure you don't keep the tank at a place where it receives direct sunlight. Fish owners often tend to overfeed the fish, which increases the phosphate levels in the water.
So, make sure you feed smaller portions of food to the fish. A great way to prevent excessive algal growth is to keep the tank clean by changing the aquarium water regularly. Make sure the water you are using is low in phosphates. If there is algal growth on rocks, plants, or other surfaces of the tank object, then remove them.
Scrape the glass clean, scrub the tank objects, wash them and vacuum the gravel and then replace them back in the tank. You can also consider adding plants in the tank, which will eat up the nutrients algae uses for their growth. You can also place algae-eating fish like otocinclus, common pleco, or Siamese flying fox.

Controlling Algae in Ponds

There are various ways to prevent the growth problems occurring in a pond. You can dugout aeration systems. Aeration system tends to inhibit algal bloom, by preventing the recycling of nutrients from the bottom sediment.
Barley straw is an environmentally acceptable and inexpensive way to prevent the growth. Proper watershed management can also greatly help to keep the growth in a pond under check. You can also consider using certain chemical treatment like cutrine in the early stage.