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• How to Remove and Prevent Algae Outbreaks in Aquariums

17 August 2022

Every fishkeeper will have at some point battled an algae outbreak in their aquarium. It’s an inevitable hurdle as there can be many reasons for algae to appear in their fish tank. This article aims to look at the best ways to solve an algae problem and to prevent it from happening again.

Algae in the aquarium
Algae is a very loose term for a large collection of photosynthetic organisms that share similar traits and lifestyles. There are thousands of different species of algae that live in every habitable space on Earth. It is not strictly limited to water either! Algae can also survive in damp conditions out of water - the algae that grows on the fur of Sloths is a great example!

In aquariums, there are a few species which are commonly seen:

• Green water - Aquarium water that has a green hazy appearance is caused by unicellular, free floating algae cells too small for the naked eye to see.
• Green spot algae - This is the algae that grows on surfaces (glass, rocks, plants) and can be hard to remove.
• Hair algae - There are many species of hair algae that can grow in aquariums. Bright green, long and stringy hair algae (often called blanketweed in ponds) or the short, dark, tufty algae known as ‘black beard’.
• Cyanobacteria - Not an algae in the true sense of the word, but a photosynthetic bacteria that is usually a blue/green colour (in freshwater) and looks slimy.

All of these algae types can become a nuisance if not taken care of. It is about managing algae in an aquarium, rather than eradicating it completely - algae is an omnipresent feature of aquatic life!

How to remove algae from an aquarium
Removing algae from an aquarium can seem a daunting task, and a lot depends on the type of algae that needs ridding. Physical removal is usually the first method to try (algae pads, scrapers etc) which can be laborious. Adding ‘janitor’ animals is can work better long term and saves doing most of the work yourself!

Where algae has grown on the aquarium glass, a good quality cleaning pad made for fish tanks will do a good job at removing it. There are a variety of tools available - from simple algae pads, scrapers and even magnetic cleaners - removing wet hands altogether! Algae on rocks and ornaments will be a little more tricky but removing them and giving them a good scrub generally does a good job. For a deep clean on non-porous decorations, NT Labs Aquarium - Plastic Plant Cleaner provides a strong solution to soak ornaments and plastic plants (in a separate container) to remove organic build up.

Green water algae outbreaks can be managed simply and effectively by using NT Labs Aquarium - Algae Gone. Algae Gone works on two fronts on algae outbreaks. It first binds the microscopic algae cells together so the mechanical filtration can remove them from the water column. Algae Gone also binds phosphates in the water to remove a major source of food for algae. Any flocculant such as Algae Gone works best when used with fine filter medium such as aquarium wool in the filter. Regular use of Algae Gone can help prevent further algae issues even when a problem is not immediate.

Hair algae is harder to remove than other types of algae. These long strands are a collection of single cell algae that form a colony. Removing the algae by physical removal will result in breaking the ‘colony’, dispersing the cells to pop up again. Removing hair algae is therefore usually a long game. Later in the article we will discuss the best ways to prevent an algae outbreak, and these methods are usually best used for hair algae removal. There are also a great group of fish and shrimp species that do a great job at eating hair algae. Look out for siamese algae eaters (Crossocheilus oblongus) and amano shrimp (Caridina multidentata) as both species are very good at eating black beard algae!

If your aquarium has a cyanobacteria problem, it has to be treated in a different way to algae. As it is a bacteria, traditional algaecides will not work. The best practice for removal is to siphon areas most affected when performing a water change. To prevent it from coming back aim at reducing excess nutrients. Regular dosing of NT Labs Aquarium - Aquarium Cleaner would also help keep cyanobacteria, as well as other forms of algae, in check. Aquarium Cleaner contains sludge busting enzymes that help control and remove waste products.

How to prevent algae outbreaks
Preventing an algae problem is usually easier than curing one. The best ways to do this is to keep a check on nutrient levels (what algae will feed on) and light exposure (what algae uses to photosynthesise).

Excessive light levels is a huge problem for causing nuisance algae. Algae uses light to photosynthesise for survival and development. Sources of excessive light can come from the aquarium lighting or the room the aquarium is placed in. It is recommended to not place the aquarium in a room that has direct sunlight to limit the light the aquarium is exposed to. Lighting an aquarium with an artificial light source is the best method of control. Regulating the aquarium photoperiod is easier with artificial lighting (by simply turning on or off the light source). If algae becomes a problem, an easy solution is to reduce the hours the light is turned on. Modern aquarium lighting, such as the ONF aquarium lights, give even more flexibility. Using the smart phone app, the LEDs can be tuned by regulating their output percentage from 0-100%. This makes it even easier to find the right balance of light to promote plant growth but limit algae problems.

Regulating excessive nutrient levels also plays a large part in controlling algae problems. Plants (and algae) require certain nutrients in order to grow. The main nutrients that can cause algae outbreaks if left unchecked are phosphates, silicates and nitrates. These naturally build up over time as byproducts of the nitrogen cycle (biological filtration) and other sources (fish food, chemical additives etc). But plants need these nutrients, so the aim is never to completely remove them in a planted aquarium. NT Labs Aquarium - Plant Boost contains macro nutrients that include phosphorus to enhance plant health and growth. It is when these nutrients become unmanageable that they cause issues with algae outbreaks.

It’s important to regularly test aquarium water to check whether these levels are getting too high. The NT Labs Aquarium Lab Test Kits provide options to test for nitrate and more recently phosphate in freshwater aquariums.

If nutrient levels are determined to be too high, there are a few ways to reduce them to manageable levels:

• Check whether the fish are being overfed. Overfeeding is the number one cause of excessive nutrients in an aquarium. The general rule for feeding aquarium fish is to give them as much food as will be consumed within one to two minutes. If there is still excess food left over after this time, they have been given too much. It’s important to remove excess food with a net or siphon to prevent waste build up.
• Regular water changes using a gravel cleaner to remove excess nutrients from the gravel will reduce high nutrient levels caused by a build up of detritus in the substrate. The removal and replacement of fresh water also dilutes nutrient levels in the water itself. This should be performed weekly or fortnightly according to your schedule. A recommended percentage of change is generally 10% of the water volume per week, or 20-25% fortnightly. This is only a guide however - many fishkeepers will change more than this if their stocking level is high or if resetting nutrient additives in a planted tank. Detritus can also be controlled by regular dosing of NT Labs Aquarium - Aquarium Cleaner. Aquarium Cleaner contains sludge busting enzymes that help control and eradicate waste products in the aquarium.
• Phosphate and silicates can be chemically removed using NT Labs Aquarium - Phosphate Remover. This aluminium oxide based product rapidly removes phosphates and silicates from the water. It is best placed in the aquarium filter in a suitable filter bag (provided). Its absorptive capacity can easily be reached, so it’s important to regularly test phosphate levels and replace the media as necessary.
• Aquarium plants absorb the same nutrients as algae. Adding some real aquarium plants will therefore help reduce nutrient levels as they utilise them - outcompeting algae in the process. Aim for some fast growing stem plants if this is the primary goal - these plants grow fast and will rapidly reduce nutrient levels in the water. For long term care, aquarium plants will flourish with regular feeding of a comprehensive liquid plant food such as NT Labs Aquarium - Plant Boost.

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