How to Get Rid of Algae in Hydroponics in 9 Easy Ways

The presence of algae can lead to major problems in hydroponic systems, especially in open systems. It can build up at any surface, and any pipe or surface can become clogged with it. 

Algae can easily ruin any set system. These can stop the flow of water by clogging inside the pipes. Not only that. When these algae start to decompose, they start to emit a very horrible odor; and if you are growing vegetables there, then these algae can prevent their growth. 

It is important to know how to get rid of algae in hydroponics because they start to consume the precious nutrients that you put for the growth of your vegetables and use them for their rapid growth.

In the presence of algae, the oxygen level of hydroponics drops rapidly. So, your plants or vegetables don’t get the needed things, and they start to feel suffocated and become weaker. 

How to get rid of algae in hydroponics

To get rid of algae in hydroponics, there are multiple ways, such as shading, UV filtering, regular system cleaning and sterilization, grapefruit seed extract, barley straw rafts, humic acid, using commercial algicides, changing hydroponic nutrients (without phosphorus), keeping the temperature low, etc.

According to your convenience and availability, you can follow one or two options to deal with this issue.

What is Algae? 

You can easily find algae in any water reservoir. The natural properties of algae are almost similar to that of plants.

For this reason, you can find that algae grow rapidly in any aquatic environment.

It only needs sunlight, water, and some natural nutrients to survive and grow. As these are easily available in our environment, algae can grow rapidly in any medium.

Their durable organism also helps them to survive and grow.

What is Algae
What is Algae?

The natural properties of algae and plants are almost similar. Like plant algae also do photosynthesis. For these similar natural properties, you can easily find algae in any hydroponic system. And when there are any algae in a hydroponic system, it starts to grow rapidly. Controlling algae is a very difficult task, especially when it is in a hydroponic system. 

How Does Algae Get Into a Hydroponic System?

Any aquatic environment (including a Hydroponic system) is one of the most common places where you can find algae. In this environment, algae grow rapidly for its versatile and durable organism. You may have a well-maintained hydroponic system; it may be sterile and perform other potential contamination sources, but you can’t make the place completely free from algae. 

How Does Algae Get Into a Hydroponic System
Algae in a Hydroponic System

As algae need very common things to grow, they can easily survive in any condition and can find all the necessary ingredients for their growth. If your system is built up for the perfect growth of plants, that means it is also suitable for the rapid growth of algae. 

In other ways, we can say you can control the growth of the algae. But to make your hydroponic system 100% free from algae is impossible. By any means, you have to ensure that these algae don’t get any chance to grow rapidly. You need to make an effective strategy and take action to control its growth of it.

How Does Algae Affect a Hydroponics System?

The complete prevention of algae from entering your hydroponics systems is an imagination. So you must be aware of all the adverse cases. Specifically, we can say that the bad effects that these algae can bring upon your hydroponics systems; if you fail to prevent their growth.

How Does Algae Affect a Hydroponics System
How Does Algae Affect a Hydroponics System?

Each healthy hydroponics system is good with small amounts of algae. But the excessive presence of them in the system can bring some detrimental effects. 

Oxygen depletion and fluctuation 

When there are too many algae in your hydroponics, then these algae start to consume oxygen from the hydroponic system. For it, the oxygen level gets depleted. And it creates huge biological oxygen demand in the system. The roots of the crops get suffocated and gradually die.

Nutrients Depletion 

For the growth of your crop, you ensure all the required nutrients. But by depleting these nutrients, algae starts to grow itself. So, the plants don’t get the required nutrients, and it prevents their growth.

pH Problem

Like plants, algae also take part in photosynthesis. At the time of photosynthesis (day), the pH level of the hydroponics system rose to its peak. At night the opposite occurs, and it causes a severe drop in the pH levels. For the presence of algae in your hydroponics, you can see a huge change in the pH scale.

On average, there will be a significant swing of almost 2 units. For this drastic change in the pH factor, the progress of the plants suffers a lot. 

Toxin Issue 

Algaes produce a lot of toxins. These toxins attract harmful fungi, which can ruin your entire hydroponic system.

9 Ways to get rid of algae in hydroponics

Here we are mentioning the nine most effective ways to get rid of algae in hydroponics. 


By installing a shade, you can easily cut the source of light. If algae don’t get sufficient light, they will not be able to make photosynthesis freely. And it can prevent the algae from growing rapidly within the reserver. You can use a solid-colored material or use a plastic cover with holes for plants.  

9 Ways to get rid of algae in hydroponics
how to get rid of algae in hydroponics?

UV Filtering

Installing a UVC light is another efficient way for water filtration. This light can efficiently eliminate all the potential microorganisms and can easily kill most of the algae present in the hydroponics system. But this is a little bit costly. 

Regular System Cleaning and Sterilization

This is the most common way that most people use to deal with algae. For proper cleaning and sterilization, you need to follow some simple steps, and they are:

Drain the entire System

The existing nutrient mix must be drained properly from the reserver. If your reservoir has a drainage system, then open the valves and keep the water draining out properly. In the end, if any amount of water is left, then remove it with a sponge.

But, if there is no drainage knob, then you need to use the ‘Pump Return Method.’ You need to run the pump until the system becomes almost dry. Again if there is anything left, clear it off with a sponge and bucket.

Making the cleaning solution:

There are three options for cleaning solutions; each is very efficient. You can choose any, depending upon your convenience and choice.

  • Bleach: Per gallon of water, you need to mix 1.3 oz of bleach. But before applying it, you have to ensure that there is nothing left in the reserver, and the bleach needs to be unscented.
  • Hydrogen peroxide: you need to use Food grade hydrogen peroxide. To make the solution, you need to add 3 ml of hydrogen peroxide for each gallon of water. The concentration will be near about 35%.
  • Vinegar: This organic Compound can also be used. But it does not sterilize the system, but it sanitizes the system.

Remove air pumps & stones

You need to check the internal section of the pump for algae. There is a high chance of its existence there. These are not easily noticeable and hard to clean.

But for proper cleaning, you need to use the cleaning solution in all sections of the pumps and the stones. For this purpose, the peroxide solution is the most effective. After cleaning, you need to leave the pump and the stones to dry.

Reach and clean all the parts

If there is any part that is very hard to reach, then you need to remove it manually, and you have to clean it with your hand. At this stage, you can also search for any broken roots or debris. If you find any e remove them manually.


Now you need to scrub the entire system carefully with a scrubbing pad and a cleaning solution. If you find any sign of algae on any surface, then you have to pay special attention there. You can also use some brush to reach the hard-to-reach areas. After completing the scrubbing process, you need to clean the entire area with a clean Rag. and you need to assemble all the pumps, stones, and other things.


After scrubbing, you need to stabilize your entire system. You need to put the solution at a higher level than usual; so that the last line, where algae were formed earlier, must cover. Now you need to run the system for at least 6 hours. 


At last, you need to drain the entire cleaning solution. And if you’re using bleach, then you need to repeat the process at least three times. Now wipe down all the internal sections of the system with a clean towel, and don’t use any cloth which has been exposed to algae. In this process, you must ensure you have raised all the sections of your reserver.

9 Ways to get rid of algae in hydroponics
9 Ways to get rid of algae in hydroponics

Grapefruit Seed Extract

For killing and preventing the growth of algae, grapefruit seeds are very efficient. The grapefruit seed extract is an anti-bacterial and anti-fungal, and antiparasitic element. Low doses of it are not toxic to the plants. You need to use 5 to10 drops of it for each gallon. 

Barley Straw Rafts

When barley straw starts to decompose, it releases a chemical solution. This chemical compound resists the algae from growing rapidly. If you have a small place, then follow an alternative method because this process is very slow and best for large spaces. 

Humic Acid

This chemical compound makes the entire water dark and resists the sunlight from entering; thus, it prevents the algae from growing rapidly. This acid brings some benefits to your plant too. 

Using Commercial Algicides

Commercial algicides are not very effective. Their efficiency is very less (after a certain period, the algae start to regrow), and if you misuse or overuse them, then your entire hydroponics system will ruin. It can easily damage any young or delicate root.

Changing hydroponic nutrients (without phosphorus)

To prevent the growth of algae, you can make certain changes to the nutrients. Sometimes this method works, but after some time again, you need to change it; this change must be in a continuous circle. You need to put a special eye on phosphorus; it must be regular there. 

Keeping the temperature low 

Low temperature is not good for the growth of algae. Keep the temperature of the nutrient solution between 65 to 70 degrees; if you want to prevent the Rapid growth of algae in your hydroponic system.

Frequently Asked Questions (FAQs)

Are algae good for hydroponics?

No, algae are not good for hydroPonics. The oxygen level of the system is reduced to a certain level for the presence of algae. It also prevents the growth of your vegetable or plant by consuming nutrients.

Do algae cause root rot?

Yes, if algae are present in your hydroponic system, then there will be a huge deficiency of oxygen. For this reason, the plant will feel suffocated, and its root will start to rot. 


If there is water on the surface, then there is a high chance of the presence of algae. It is very hard to treat them and almost impossible to get rid of them, especially in a hydroponic system.

By using the above-mentioned methods, you can only keep them in a controllable position. Almost each hydroponics system is good with a certain level of algae. But these are very harmful to the growth of your plants or vegetables.

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