How to Remove Brown Algae from the Fish Tank?

Brown algae, which are also known as diatoms, can be quite tricky to remove from the aquarium. To make matters worse brown algae spread quite fast.

Normally, you can find brown algae growing on the aquarium glass, any decorations in the aquarium, and even on the gravel. Once it appears, it can rapidly spread to most of the the aquarium and create a thin, dark brown coating.

The good news is that if you know the cause, it is easy to stop brown algae from growing in your aquarium. A few preventative measures will have your tank looking great and algae free.

Let us know a bit about brown algae before we start removing and preventing it from attacking the aquarium.

What are brown algae?

Brown algae are the common name that refers to diatoms, class Bacillariophyceae.

The alga is a single-celled organism and is brown in color. It can occur either as solitary cells or in colonies. It finds its way into both freshwater and saltwater aquariums.

It has a bony structure that is composed of silicon nitride.

All the brown algae species create an opal-like crystalline covering around its cell walls. This covering works as armored protection for these tiny organisms.

They are immobile and because of their heavy cell wall, they sink to the bottom of the fish tank. This creates a thin dark brown film across the bottom of the aquatic environment.

Is Brown Algae Dangerous?

Normally, brown algae diatoms are not harmful to your aquarium fishes, but it needs to be kept in check.

Some fishes also like to eat brown algae, which can help in cleaning your tank.

Although it’s not dangerous, it’s still recommended to prevent brown-green algae from coming into your aquarium. These diatoms don’t stick together and can look like patches of brown color, which can also ruin the look and aesthetics of your aquarium.

Despite not being harmful, it’s still a nuisance and is best to prevent it.

What are the causes of brown algae?

There are many causes for the brown algae developing in the aquarium. It is a common occurrence in a newly setup aquarium.

Insufficient light

If your aquarium is kept in dark most of the time, it’s more likely to get brown algae.

One of the major reasons for this is that the aquarium plants that grow in light also compete for the same nutrients that brown algae uses to service and grow.

Water chemistry not optimal

Excess silica on nitrates in water for an abundance of nutrients can cause the growth of brown algae.

Silica can build up in the aquarium from tap water that is high in silicic acid. It can also lead from some type of substrates that you may be using such as silica sand.

Excess nitrates and nutrients

Diatoms feed on nitrates and these can build up in your fish tank because of eaten food, material, or from overstocking fish.

Overcrowded tanks have a tendency to lead to an over-abundance of fish waste (excess nutrients) that contributes to the development of brown algae.

Poor oxygen circulation

Low levels of oxygen can lead to the growth of brown algae.

It is usually a result of overstocking the aquarium where everyone competes for oxygen.

The best ways to remove brown algae from the aquarium

Here I have discussed some of the best ways to remove brown algae from the aquarium.

Most of these methods work by cutting down on the nutrient supply that is essential for brown algae growth.

Physically remove by cleaning up your aquarium

One of the best methods to remove brown algae from a fish tank is to physically remove it.

You can use a suction or your hand to remove the algae. Since brown algae spread fast, when you manually remove it, this slows down the growth. This also makes the other methods (covered later in this article) more effective.

You can simply wipe and remove the brown algae, but if you need a more effective solution, it’s better to also vacuum the brown algae burrowed within your tank’s gravel.

While vacuuming, go ahead and push the tip of the vacuum down into the bottom of the substrate. The gravel will tumble over and this way most of the brown algae will come off. Then you can easily suck it through the hose of your vacuum.

But vacuuming the sand gravel is a bit difficult, as the sand grains can get stuck in the vacuum hose. Start by hovering the vacuum over the surface of the sand. This will help to remove any fish waste.

Next, proceed by pinching the nose of the vacuum. By doing this, you will enable very little suction. Break loose the brown algae by moving the sand using the hose of your vacuum.

Now go ahead and lift the vacuum, and un-pinch it and remove any brown algae. Repeat this again and again until you are satisfied that the sand is all cleaned up.

To remove the brown algae from the glass place the scrubbing pad on the tank glass. Scrub away the algae, take the scrubbing pad out and squeeze it out into the bucket. Do this again and again until all the aquarium glass has been cleared.

Wipe off any time decorations that may be affected, wipe off all the surfaces inside the aquarium.

Improve the lighting

Make sure there is adequate lighting for 8-10 hours in and around the aquarium. Try

If there are no corals or plants in the aquarium, you can reduce lighting to just 6 hours per day to help in removing the algae.

Use filtered water

Use filtered water. This water is free from nitrates and silicates.

Check the water from your tap to see if it contains silicates, this is a common cause of brown algae.

Clean the filters and change the water

Regular maintenance such as changing the water and cleaning the filters would make sure there is a good flow of clean water that is free from silicate and nitrates. Always change the water and clean the aquarium at least twice a week. Clean more if the algae are becoming a problem.

Remember that adding water is not the same as replacing water. At the bare minimum, replace at least 10% of the water twice a week. Consider using things such as air pumps or powerheads for increased water circulation.

This will in turn circulate oxygen more effectively. It will also help to retain high levels of oxygen and good oxygen circulation will help to prevent brown algae from growing.

Reduce the nitrate level

The Nitrate level needs to be decreased to the control of brown algae. That can be achieved by adding a few drops of vodka in the water. You need to monitor the Vodka dose as it can be harmful to your fish.

You can also reduce the nitrate levels by using nitrate absorbing filtrates that are placed within the filter.

If you can keep the nitrate levels low in your fish tank, it will make sure brown algae doesn’t appear in your aquarium, and even if it does, the growth rate of it is low.

Use decorative material that does not have silicate content

Make sure the gravels, pebbles, and rocks do not have silicate content.

Read the label carefully to avoid high silicate.

Do not overfeed

Do not offer extra food to the fish. Food that fishes do not consume will just end up as nitrate in the water.

One of the best ways to remove brown algae is by paying close attention to feeding time. Feed slowly for two minutes. Do not let any uneaten fish food sink to the bottom.

Do not overstock!

Do not overstock or overfill your aquarium.

Their waste products, dying material, loose waste will increase the likelihood of nitrates and increase the risk of brown algae.

Introduce a few fishes that eat algae

An easy brown algae removal technique would be to introduce a few fishes that eat algae.

Fish like otocinclus, siamese algae eaters, and some snail species. These fishes are great for keeping brown algae to a minimum because they use it as a food source.

Keep a few live plants

In addition to algae-eating fish, have a few live plants in your tank.

It is a great way to eliminate many of the nutrients that promote the growth of algae.

Java moss and anubias plants serve as a good plant that can thwart brown algae growth. When you have these plants growing in the aquarium, they will compete with brown algae for the same nutrient, thereby somewhat starving the algae and slowing down the growth.

Preventing brown algae from coming back

After removing the algae, it is imperative to keep a low nitrate environment. This will ensure the brown algae is starved and will not be able to grow in the aquarium.

If your water contains silicates, it will be necessary to use RO water during water changes.

Diagnose your tank and determine the root cause promoting the growth and take an all-encompassing approach while maintaining your aquarium.

Aquarium maintenance is both an art and science, and simply dumping new water and food periodically is not enough.

The brown algae are one of the worst and most common types of algae. Getting it under control is difficult but not impossible.

The list above outlines the ideal ways of removing the brown algae and preventing it from coming back.

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