The War on Algae

The dreaded algae problem. What hobbyist hasn’t encountered it? But you do not have to experience algae in your Nature Aquarium.

Algae usually appears when there is an imbalance in nutrients, water circulation, CO2, oxygen and light. Too many nutrients and too little CO2 will cause algae to appear. On the other hand, too much light but too few nutrients and CO2 will also cause algae. Many hobbyists think that lowering nitrates and phosphates (which are nutrients) will reduce algae outbreaks, when algae actually thrives in a low-nutrient environment.

These are the main reasons why algae appears:


1. Not enough beneficial bacteria in a new setup

Algae typically appears in the first couple of months of a new setup. This is because a newly established Nature Aquarium does not have enough beneficial bacteria to convert ammonia through the nitrification cycle. The overabundance of ammonia will cause algae blooms. Algae will cover most part of the plants, blocking light and depriving the plants of nutrients. Plants will eventually die.

ADA substrate foundation PowerSand and five essential additives (Bacter 100, Tourmaline BC, Clear Super, Penac P and Penac W) are the main ingredients needed to jumpstart the growth of beneficial bacteria in a Nature Aquarium.

We like to start a new Nature Aquarium using the immerse method. While you do not need to follow this procedure, it will help prevent an early algae bloom, and give your foreground plants optimal conditions to become established.

This is the immerse method:

Build the substrate foundation using ADA PowerSand and add the five essential elements. Then put down a layer of ADA AquaSoil before filling the Nature Aquarium with water up to the top of the soil and planting it with foreground plants. Do not fill the aquarium with water yet; cover the Nature Aquarium with stretch film to retain the moisture inside. Provide enough light for a duration of eight to ten hours a day. Watch the foreground grow for the next two months, and do not add water.

After 2 months, beneficial bacteria will now be living inside the substrate and will be in a sufficient supply to convert excess ammonia to nitrate. At this time, you may now fill the Nature Aquarium with water. Make sure to use tepid water: icy cold water may harm the foreground plants that were planted. Do several full water changes to ensure removal of any trace of nutrients in the water column which may cause an algae bloom.


2.  Insufficient water circulation

To ensure the nutrients and CO2 circulate throughout the aquarium and reach all the plants, it is important to have strong water flow. The flow rate should be five to eight times the Nature Aquarium volume. Choose a filter system with the right flow rate or supplement it with circulation pumps. When plants have sufficient access to the nutrients and CO2, they leave little remaining in the water column for algae to use.


3.  Insufficient surface agitation

Surface agitation will add oxygen to the system and will prevent surface scum from forming. However, too much surface agitation will also offgas the injected CO2. We suggest the use of an air pump to supply surface agitation, but only when the lights are turned off.

Plants breathe in CO2 when the lights are on and begin using oxygen as soon as the lights are turned off. When this happens and there is lack of oxygen in the system, plants, fish and beneficial bacteria fight for the dwindling oxygen. The first to suffer is the beneficial bacteria, which will die off, resulting in increased ammonia and, eventually, algae blooms. Thus the appropriate oxygen level is as important as CO2 supply.

During the summer when temperatures are higher, beneficial bacteria activity increases and demands more oxygen. It is very important to increase surface agitation when temperatures rise.


4. Imbalanced light levels, CO2 concentration and nutrients

The rate at which plants absorb CO2 and nutrients depends on the amount of light provided. The more light, the more CO2 and nutrients plants need. In most cases, we provide too much light but do not measure the CO2 concentration and nutrient availability, and often, we haven’t supplied enough of either. When this happens, algae blooms will appear. Make sure that you measure the water chemistry when the lights are turned on and when they are turned off. This will give you an idea of whether you need to increase or decrease your CO2 and nutrient dosing.

As a rule of thumb, we would like to achieve a pH of 6.4 and kH of 4 to get the maximum CO2 concentration of 30ppm. NO3 and PO4 can be dosed daily to attain an optimum concentration of 30ppm and 2ppm respectively.


5. Improper aquarium substrate, filter and plant maintenance

When this regular maintenance is ignored, organic matter starts to build up in the substrate and filter media. Regular light substrate vacuuming and cleaning of the filter media will decrease accumulated organic waste, which can clog the system and increase ammonia. Light vacuuming will also aerate the substrate, which helps plant roots get oxygen, and also helps beneficial bacteria convert ammonia to the nitrate that becomes food for the plants.

Decaying leaves generate ammonia. Trimming plants of dead leaves will eliminate the ammonia source and promote new growth.

A regular water change of 10% every week is encouraged.


6. Not enough shrimp, algae-eating fish or snails

Takashi Amano introduced Japonica shrimp to the Nature Aquarium and thus they have become known as Japonica Amano shrimp. These shrimp are very good at controlling hair algae as well as consuming uneaten fish food and breaking down fish waste into smaller particles that beneficial bacteria can feed on. Shrimp also eat certain bacteria and other micro-organisms, preventing these from overpopulating and creating an unbalanced system. We advise two Amano shrimp per gallon of Nature Aquarium volume.

Trumpet snails are helpful in aerating the substrate. However, they tend to multiply rapidly so make sure you keep their population under control.

So-called “sucker fish” such as otocinclus, small baby plecos or ancistrus are very good at cleaning diatoms and bacteria from plant leaves, decorative stones and driftwood. If you decide to get plecos or ancistrus, make sure to rehome them appropriately when they become too big for the system.  See the sequence of Ancistrus cleaning a stone.

True Siamese algae eaters will consume black beard algae and hair algae. However, they can grow to a size of more than 14cm and can become very aggressive towards other fish, so they are not appropriate for all aquarium setups.


Identifying Algae and How to Eradicate It


Cloudy/Milky Water

This is not actually a type of algae, but a bacteria bloom. It usually happens when the tank is new or the substrate disturbed, and excess nutrients are released into the Nature Aquarium. When this happens, the bacteria population explodes exponentially and results in a cloudy or “milky” appearance, which is bacteria floating in the water.

Change the water, wait it out, and the bacteria bloom will disappear in a few days.





 Green Water

Green water is an excess of tiny organisms called phytoplankton, which are part of the algae family. Green water is usually caused by high ammonia levels combined with too much light. It often occurs during the summer when the temperature is warmer, or if you have placed your Nature Aquarium near a window that has a prolonged photoperiod in the summer.

Obstruct any unwanted light, perform a water change, and use a UV filter clarifier.




Brown Algae (Diatoms)

Brown algae (or diatoms) is neither bacteria nor algae. It appears when there are excessive silicates coming from the substrate or from decorative stones, combined with a low-light condition. It can also come from the water source.

Remove as much as you can using a toothbrush and a narrow siphon hose. Change the substrate, use clean reverse osmosis water, and add fish that will each these algae, such as otos, plecos or ancistrus.





 Green Dust Algae

Green dust algae appears when CO2 and nutrients are low.

Wipe off as much as you can and increase CO2 and nutrient levels. Wait out its life cycle.








 Green Spot Algae

Green spot algae appears when CO2 and phosphate are low.

Remove using a blade scraper and increase CO2/phosphate levels.

Both Green Dust Algae and Green Spot Algae are most commonly seen on the inside walls of aquarium tanks.  These algae develop during the initial installation period of an aquarium as well as on the glass surface and white diffusion filter of POLLEN GLASS in a mature aquarium.

Remove the algae growing on aquarium tank walls with an ADA PRO RAZOR, and then change the aquarium water.  When you use a Pro Razor near the substrate area of the layout, be cautious not to let sand get in between the blade and the glass surface.   Sand can easily scratch the glass.

Brown Algae, Dust and Green Spot Algae can be reduced significantly by introducing a team of Ancistrus (‘sucker fish’).  See how a team of Ancistrus clean a stone in just two hours.

You can remove green algae accumulated on the diffusion filter of a POLLEN GLASS
with SUPERGE, ADA’s glassware cleaning agent.

Be sure to watch “How to Clean a POLLEN GLASS” on our maintenance section.

Blue-Green Algae

Blue-green algae is a form of bacteria and not an algae. It will cover a large surface area if not treated immediately. It is caused by low nitrates in a high-light environment.

To remove blue-green algae, use ADA Phyton Git or a generic brand erythromycin antibiotic. Increase nitrate levels to prevent it from reappearing.








Hair/Thread Algae

This algae usually appears when CO2 and nutrient levels are very low, and light is excessive.

Remove as much as possible using a toothbrush and a narrow siphon hose. Then increase CO2 and nutrient levels.








Staghorn Algae

Low CO2 and/or fluctuating CO2 levels usually cause staghorn algae to appear.

Remove as much as possible using a toothbrush and increase CO2 concentration.








 Black Beard Algae (BBA)

The hardest algae to remove. Black beard algae is caused by high Nitrate levels combined with fluctuating and/or low CO2.  Slow-growing aquatic plants are more vulnerable to the algae problem than the fast growing kinds.  A group of plants in the Anubias family is a good example.  When diatom algae, which are often seen on Anubias’ leaf surfaces during the initial aquarium installation period, are not removed properly, green algae may start spreading over the diatom algae.

– ADA Phyton-Git Method for BBA algae on Anubias

In case a large amount of BBA growing on Anubias leaves, lower down water level until Anubias leaves are exposed then apply a diluted PHYTON-GIT solution using a paint brush.  Add water back to the Nature Aquarium after 5 minutes.
*Do NOT apply PHYTON-GIT to any other aquatic plants.

– ADA Phyton-Git Method for BBA algae on layout stones and driftwood

Black and tough beard-like algae growing on stones and driftwood can be seen in the aquarium with a high nitrate level.  Please pay close attention and take care of them before they become unmanageable. After scraping off algae with PRO-PICKER, release Siamese Flying Fox and Caridina japonica in the aquarium.  If the condition is critical, remove
water from the aquarium, and cover the affected area of stones / driftwood with a paper towel, soaked with several drops of PHYTON-GIT, overnight. Then, fill the aquarium with water in a usual manner.

– SeaChem Excel Method

Remove as much as possible by pruning infected leaves. Introduce Siamese algae eaters if appropriate for your aquarium, and dose Seachem Excel to increase CO2 levels. Follow dosage as prescribed on the bottle.  Use half dosage of Seachem Excel if you have shrimps in your tank. Turn off all filter pumps and water current during treatment for 20 minutes.   You can use a syringe to target treatment heavily infect BBA areas.

– Hydrogen Peroxide Method

Same method as Excel.   Turn off all filter pumps and water current during treatment for 20 minutes.   You can use a syringe to target treatment heavily infect BBA areas.  Use hydrogen Peroxide 3% solution (obtained in any drug stores).  Use 1ml of hydrogen peroxide per liter of tank water.



We recommend Dusko Bojic aka Che Guebuddha’s Aquarium Algae ID and James’ Planted Tank – Algae Guide for more information on algae and prevention methods.

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