How To Control Algae in a New or Established Planted Tank

Algae can be a major inconvenience for anyone who owns a planted tank. In fact, many people struggle to deal with these growths effectively and thoroughly. Unfortunately, this is because of the diet of algae.

These pesky organisms thrive on the same nutrients that feed your plants. So it can be easy for them to expand alongside your greenery and take up space in your aquarium.

You might be wondering how you can control algae growth. So, in this post, I’ll talk about ways you can slow down algae growth in your tank, or get rid of it altogether. Some tank ecosystems do need algae. For instance, certain fish breeds and aquatic pets feed on algae.

You’ll need to consider this as you read through this guide. As a tank owner, you can have algae growth in your tank. You just don’t want it to get out of control or cause a decline of health in your planted tank.

Reasons Your Planted Tank Is Filled With Algae

1. You Have Too Much Ammonia in Your Tank

 Algae proliferate in planted tanks for all kinds of reasons. However, one of the main causes of algae overgrowth, in a planted tank, is spiked ammonia levels.

Algae bloom when ammonia is present in your planted tank. Usually, this happens when an aquarium is full of waste or has not been properly cycled.

Again, small growths of algae can be alright. Out of control blooms of this organism, though, will smother your plant and cause it to die. So you want to deal with this issue fast. 

2. Your Water Is Stagnant

Ammonia is not always to blame for algae issues though. In some cases, stagnant water could be the reason algae is growing in your planted tank. Surface tension is important in a planted aquarium. You want your water to be moving and well oxygenated.

When your aquarium water has no movement and flow though, microorganisms, like algae, sprout in your tank more easily. Pumps and other devices can help create surface agitation in the water, which will help oxygen move in your tank.

This will prevent algae from blooming. I’ll talk more about pumps and how you can keep your water from becoming stagnant later on in this post though.

3. The Lighting In Your Tank Is Too High

Plants need light to thrive in an underwater environment. However, when you shine too much light on your plants, you can cause major issues. This includes plant damage and plants “melting”.

Once this happens, organic waste is naturally left to float in your tank as your plant wilts and dies. This will create the perfect environment for algae growth.

You want to keep your tank well-lit of course, but too much light, and sometimes too little light, will create algae issues for your planted aquarium.

4. You Don’t Have Healthy Plant Growth

An unhealthy planted aquarium will lead to algae growth. If your plants can’t sustain themselves in your tank, they will die and cause water discoloration and contamination. All of this of course leads to algae multiplying in your water.

A planted tank needs more than good lighting to thrive. Nutrient levels, waste levels, oxygen levels, and many other components contribute to plant health. Planted tanks should be well maintained and cleaned regularly to prevent out of control algae growth and plant death.

I’ll talk more about this in the final section of this post though.

How Can You Control Algae Growth In Planted Tanks?

There are a number of ways you can manage algae growth in your planted tank. The most effective measures are preventative. Here I will talk about ways you can prevent algae from growing out of control.

These steps will stop algae from multiplying before they even enter your tank. However, if you do have a lot of algae in your tank, we will also talk about ways to reduce algae growth. So keep reading!

1. Make Sure Your Tank Has Beneficial Bacteria Growth

Cycling your tank before you put in your plants, fish, and a lighting system is essential. You want beneficial bacteria to grow naturally in your tank. This way ammonia levels will not increase when plants and other tank life are added. Most algae growth is due to high levels of ammonia.

If you have beneficial bacteria in your planted aquarium though, it will make it harder for algae to propagate in your tank. Certain bacteria help break down waste and keep ammonia in check. Really, this preventative measure can take care of your algae issues promptly and effectively.

2. Buy The Best Filter For Your Planted Tank

Buying a filter for your tank can help you achieve similar results. Beneficial bacteria growth is important, but you also need mechanical filtration from a filtering system to keep algae and other unwanted growths out of your planted tank.

Large pieces of debris and other floating waste can accumulate in tanks and create an unhealthy tank environment. Unfortunately, beneficial bacteria can’t get rid of every bit of waste in your tank. This is why having a good filtration system is necessary.

With a good mechanical filter and chemical filter, you can trap particles and keep your water clean and clear. So I recommend investing in a high-quality filter for your planted tank!

3. Change Your Water Frequently

Filtration on its own won’t keep your water free of algae. Of course, biological filtration and other types of filtration are crucial. Still, they do have their limits. This is why water changes are so important for your planted tank.

If you don’t change your tank water, waste will saturate your aquarium and ammonia will spike. So, you want to make sure to do a water change at least once a week to keep your tank healthy and in top shape.

You do not have to do a full tank change all the time. Just try and change around thirty to fifty percent of your water each week for the best results! How much water you change will depend on your aquarium size. But this is a good starting number for a water change.

4. Check Ammonia and Nitrate Levels

Along with filtration and water changes try and test your water every now and then. It is possible for your water to look perfectly healthy, but still have very high levels of ammonia and nitrates. So test your planted tank. This will prevent most tank issues you have.

And if you notice any color changes or see algae start to grow, also do a test of your water.

This preventative measure will help you nip any algae problems at the bud. You can figure out if ammonia is causing your algae issues, or if something else is going on.

5. Trim Your Plants and Clean Your Tank of Plant Material

I talked about this in the beginning section of the post, but you want to get rid of any organic plant waste floating around in your tank. Plant materials decay fast and worsen the water quality of your planted tank.

So you need to get leaves and other plant droppings out of your tank as soon as you can. This way algae cannot grow as easily. In addition, make sure to prune your plants when they get too big.

Plants need to be trimmed to stay healthy within your aquarium. Again, you don’t want a rotting plant sitting in your tank. So try and keep up with your plant’s needs by trimming it. Just ensure that you are removing all the trimmings you cut off your plant.

6. Get a Fish or Tank Pet That Eats Algae

Sometimes, you just need the right pets in your planted tank to keep algae from blooming out of control! Certain fish species, as well as, other underwater pets can help get rid of your algae problem rapidly.

Personally, I recommend getting amano shrimp for your tank. These small invertebrates love eating algae. They are also great at cleaning up fish waste and other debris that is stuck floating around in your planted tank.

With this type of shrimp around, algae will grow less and your tank will stay cleaner for a longer period of time!

There are other pets you can choose from too. Snails are another type of aquatic creature that will clean up messes in your tank well. But fish like plecos and Siamese algae eaters can be handy for your algae problem too!

Just pick out something that fits with your planted tanks aesthetic and water conditions.

7. Maintain Healthy Tank Conditions For Your Plants

If your plants are not healthy, algae will bloom in your tank. It is as simple as that. Poor plant health leads to all kinds of imbalances in your aquarium. So you want to make sure that the conditions of your tank are ideal for all plant life!

Water changes are only one part of your tank maintenance. Really, there are many other elements of plant care to consider. For instance, plant lighting should be balanced within your aquarium. As I mentioned before, too much lighting can disturb plant life and create the possibility of algae growth.

So make sure you are limiting light exposure to tolerable levels. You do not want to keep your tank lights on all day. Around five to six hours of light is good for a new tank. But you can slowly up this number as your tank matures.

Really, though, light requirements will depend on the type of plant you have and how settled the plants in your tank are. So do a little bit of research before turning on your tank light.

In addition to this, you also want to make sure that nutrient levels are sufficient within your tank. Root tabs, fertilizers, CO2 injections, and other commercial products can be used in your tank to keep your plants well-fed and growing. So keep this in mind as you set up your tank.

And, of course, you want to make sure that temperature, Ph levels, and other water measurements are suitable for your plant. Each plant species has its own care requirements.

As a tank owner, you want to be knowledgeable about care and the water conditions your plants need. Look up information online and adhere to your plant’s biological demands to keep them healthy and thriving!

8. Create Water Movement In Your Tank

Lastly, oxygen and water flow should also be monitored in your planted aquarium as well. You want surface tension in your water so algae will not bloom. Installing an air pump into your aquarium, or using a filter that creates water flow can help with this issue tremendously. 

Just make sure that any devices you buy creates enough movement within your planted tank. If the surface tension is too low, algae will continue to grow in your aquarium. Really, the flow rate and power of your pump should correspond to the amount of water in your aquarium.

Additional Tips to Keep Your Planted Tank Algae Free

In general, you want to keep watch of your planted tank and look out for any discoloration in your water. Algae come in many varieties and types. Tanks can turn green, brown, yellow, and many other colors.

If you notice these changes in your water early on, you can deal with algae growth fast and prevent it from overrunning your tank.

It can be a hassle to constantly maintain and monitor your planted tank. But you should get in the habit of doing this if you want to run a successful in-home planted aquarium.

This includes looking out for your plant’s wellbeing as well. You always want to make sure that your tank water is changed, kept well filtered, and that debris is manually removed or vacuumed out. Most planted tank issues, including issues with algae, stem from poor water quality with spiked ammonia levels.

If you can keep up with tank maintenance regularly and keep a cleaning schedule, ammonia levels will stay down. This will keep your plants healthy so there is less of a chance that algae will bloom in your planted tank!

Bart Sprenkels

I have been keeping multiple aquariums since I was 18 years old. Just like many of you, I started with two goldfish but quickly learned they were not suitable for aquariums. Later, I switched to a tropical community tank and I also have two pet musk-turtles in a bigger aquarium. You can read more about me here.

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