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How to Get Rid of Algae in Aquaponics

If you’ve been doing aquaponics for a while you may have already resolved the issue of algae in aquaponics.

If you’re new to the subject, you’re going to need to know everything about Algae and how to eliminate it from your aquaponics system.

The Problem With Algae in Aquaponics

Algae is a form of food for some fish which may leave you wondering is algae bad for aquaponics?

The simple answer is yes.

A handfull of Algae
A handfull of Algae

Algae don’t just cover the sides of your tank, it can also cover the roots of your plants and prevent them from getting the nutrients they need.

Plants absorb oxygen through their roots and oxygen is essential for plant health. Algae covered roots can’t access oxygen easily. They basically suffocate.

Research shows that when plant roots have access to a high level of oxygen the root mass grows faster, this feeds the plant and allows it to grow faster and stronger. Depriving your plants of oxygen is obviously not a desirable scenario.

It should be noted that a little algae doesn’t present an issue. That means if you’re starting to get algae around harvesting time you can afford to wait and harvest first. But, once you’ve harvested you need to tackle the algae.

It’s not just that it can deprive your plants of valuable nutrients by smothering their roots. Algae also need oxygen to flourish and, because it lives in water, the algae is likely to be removing dissolved oxygen from the water, effectively reducing the oxygen available for your plants.

It also reduces the amount of oxygen available for your fish, which will negatively affect their health and your entire aquaponics system.

Don’t forget, large amounts of algae can actually start to block pipes in your system, dropping the efficiency of your aquaponics system or even stopping the flow of water and nutrients.

That’s why it’s essential that you discover everything you need to know about removing algae in aquaponics.

How Algae Grows

Algae is a form of plant life, in fact, it is made up of several different types of plant-like organisms. There are actually a number of different types of algae, it can appear slimy, bubbly, stringy, or even fury and in an array of colors. But, all types of algae have the same needs, that’s light, air, and nutrients. If the algae has this it can multiply surprisingly quickly.

The biggest issue is that algae spores are too small to be seen and travel in the air, that means no matter how hard you try they will end up in your tank. This doesn’t just give them the nutrients and light they need, your aquaponics system also gives them warmth and an established system to call home. It’s ideal for them.

Once a spore has arrived it will start to multiply, the first you’ll know of its presence is when it has multiplied many times and becomes visible to the naked eye.

Best Methods of Stopping Algae Growth

You can simply scoop algae off the top of the water or clean the sides of your tank regularly. This should remove most of the algae growth, but, it is not the most efficient method and, if you forget it for a couple of days, you may find that the algae has quickly grown out of control.

That’s why you need to act fast and understand the best way to stop algae from growing.

The best way is to deprive the algae of one of the crucial elements it needs for growth.

As nutrients and oxygen are present in the water, and you need them to be your fish and plants, the best option is to deprive the algae of light. Here are a few methods that can work for you:

Cover The Tank

If you cover your tank your fish will not be bothered by the dark, but you will deprive the algae of much-needed sunlight. That will prevent any spores from multiplying and stop the algae before it becomes an issue.

You can put a lid on and paint the sides of the tank black. The lid will also minimize mosquitos.

Example of algae growth in sump tanks
Example of algae growth in sump tanks

Add 1 Inch of Grow Media

You also need to block the light in the grow bed. if you don’t, the algae will start to multiply there instead. The easiest way to do this is to add at least one inch of dry media onto your existing grow media. The new grow media will not get wet during the ebb and flow cycle, preventing any algae spores from getting the light they need.

UV Clarification

It’s also worth considering using an ultraviolet filter tube. This is a like a small lamp that goes into your water. The light emitted by the clarifier is UV and this sterilizes the water around it. Sterilizing the water means that the algae spores can no longer reproduce. This effectively halts the progress of the algae, protecting your aquaponics system in the process.

Introducing algae eaters

You can also consider using algae eaters. There are some fish that actually enjoy eating algae. One of the most common ones is Hyposomus Plecostomus, although it should be noted that these type of fish only eat algae when they are small, once they grow bigger they prefer to eat plants, that means you need to keep them well away from your plants.

Humic Acid

This chemical can be added to water to reduce algae growth. It is very effective at darkening the water, depriving the algae of sunlight and preventing it from growing. However, it should be noted that when added to shallow water, humic acid can actually encourage algae growth, but the same is not true when added to deeper water.

It’s also worth being aware that humic acid is actually good for your fish and plants, encouraging nutrition growth, making it double beneficial to use in your aquaponics system.

In fact, adding barley straw can also have a similar effect on the algae in your system, and is worth considering if you’re trying to keep your system natural.

Mechanical Filtration

It is also possible to remove algae through filtration. A mechanical filter can be installed in your system that all water must go through. The mechanical filter will remove the algae and spores, allowing you to focus on growing better crops.

Final Thoughts

Algae is not good for aquaponics.

Getting the balance right in an aquaponics system can be difficult, especially when an enemy like algae can start establishing itself without your knowledge. However, being vigilant and understanding the best way to deal with and prevent algae in aquaponics, means that you can continue to grow fantastic crops without giving into algae, or anything else.

Blocking light is definitely the easiest way to kill the algae, however, you need to be careful that you’re just killing the algae and not damaging the aquaponics environment.