Understanding the Nitrification Cycle in Aquaponics: A Complete Beginner's Guide

What Is the Nitrification Cycle in Aquaponics?

Aquaponics is more than just adding fish and plants together in water and expecting them to grow. It is a manufactured ecosystem that replicates nature.

The nitrification cycle in aquaponics refers to the process that converts ammonia to nitrite and then into nitrate. You see, in your aquaponics system, you'll find the liquid fish waste of ammonia is toxic to fish. It needs to be converted to nitrite, which is still toxic to fish, but can be converted to nitrate, which is only toxic to fish in large quantities. We need natural nitrifying bacteria to turn the toxic ammonia-filled fish waste into liquid fertiliser for your plants. 

Understanding this nitrification cycle is crucial for a successful aquaponics system.

Nitrifying Bacteria in Aquaponics Systems

Nitrifying bacteria colonise the aquaponics system, ensuring a large enough colony to convert ammonia into less harmful compounds.

The good news is that this bacteria is everywhere in nature and will naturally colonise your aquaponics system in time.

There are two main types of nitrifying bacteria involved in this process:

• Nitrosomonas: Converts ammonia into nitrite.

• Nitrobacter: Converts nitrite into nitrate.

Nitrogen is needed for plants to thrive, but as we get this nitrogen from fish waste, we need to ensure the setup is safe for fish, and that's where the different forms of nitrogen (nitrate and nitrite) come into play. We can only consider the ecosystem safe for fish when nitrate is present in good, consistent numbers and there is no more ammonia or nitrite.

This photo shows the water testing using an API Freshwater Master Test Kit ~ which includes the ammonia, nitrite, nitrate and pH tests.

In this example, as there is still nitrite present (the purple colour), the aquaponics system isn't cycled yet. We need to ensure the nitrogen is converted from nitrite to nitrate (the less toxic form of nitrogen to fish) to support both the fish and plants.

Plants need nitrogen, but the fish can be harmed if your aquaponics system has too much nitrite, so the nitrogen cycle is an integral part of the cycling of your aquaponics system to ensure that usable nitrogen is made available for plants without harming the fish.

Monitoring the Marine Nitrogen Cycle in Your Aquaponics System

The term' Marine Nitrogen Cycle' is often used to describe the processes at work in aquatic ecosystems, including aquaponics systems.

Understanding this cycle is critical for maintaining a healthy system for your fish and plants. You do this through regular aquaponics water testing to ensure the safety and stability of your aquaponics system.

This helps you monitor the levels of ammonia, nitrite, and nitrate. Nitrogen availability is essential to monitor as part of caring for your aquaponics system, and that's all forms of nitrogen.

How long it takes to cycle your system and get the amount of nitrogen at the correct levels for healthy fish and plants will depend on several factors:

• Climate: Cold temperatures take longer for the cycle to complete.

• Bacterial Kickstart: Adding bacteria to kickstart your biological filter can speed up the process.

The Needs of Nitrifying Bacteria

Part of understanding the nitrogen needs of your aquaponics system and the biological processes involved in understanding the role nitrifying bacteria plays in the conversion of ammonia to nitrate through the nitrification cycle.

For nitrifying bacteria to thrive, they need:

• Water: A consistent supply of water.

• Oxygen: Adequate oxygen levels in the water.

• Ammonia or Nitrite: These compounds are their food source.

The bacteria need a home within the system, often called the biological filter, where they can colonise and grow.

Troubleshooting Your Aquaponics System Top Tip

When anything goes wrong in your aquaponics system, always start by checking your water tests.

Aquaponics water testing will help you pinpoint any issues with the nitrification cycle.

By understanding and maintaining this cycle, you can prevent crashes and ensure a healthy, thriving aquaponics system.

Understanding the nitrification cycle is fundamental to the success of your aquaponics system.

With this knowledge, you can create a balanced, sustainable ecosystem that supports both fish and plants. Happy harvesting!

Learn More About Aquaponics

To dive deeper into the fascinating world of aquaponics and gain step-by-step guidance, get instant access to your free online aquaponics mini-course. This course will show you how aquaponics works and what you need to take the next step in setting up your system. Sign up for a FREE Aquaponics Course Online Now.

Want to explore aquaponics more? Check out my courses page today.

Check out My YouTube Channel 'Candy The Aquaponics Lady'

Aquaponics is an ecosystem, and with anything it takes time to learn how it works. So, sit back and binge watch my 'how to' playlist and the 'Water Quality Made Simple' Playlist, and learn the next steps in your aquaponics system as you create the ecosystem.

Here are the next 2 videos I recommend you watching to create your ecosystem ~ before you add any fish

How Aquaponics Works as an Ecosystem

How to Cycle Your Aquaponics System (How to colonise it with bacteria)

Learn More About Aquaponics

Check out the COURSES page to learn how you can get started with aquaponics now. Click HERE.

Want to help out and Feed my Fish?? (They don't drink coffee)

Candy Alexander is a dedicated aquaponics enthusiast with a wealth of formal training in aquaculture. Over the past 15 years, Candy has been deeply immersed in both commercial and backyard aquaponics, honing her skills and expertise in this sustainable farming method.

Candy's passion lies in making aquaponics accessible to everyone. With a mission to simplify aquaponics, she believes that anyone can embark on this sustainable journey.

She encourages those new to aquaponics to "kick the tires" without a significant financial investment. Her guidance focuses on helping people start their aquaponics journey with small-scale systems, ensuring a low barrier to entry for newcomers.

Candy shares practical tips, step-by-step guides, and personal stories to inspire and guide readers on their aquaponics adventure. Whether you're a seasoned farmer or a curious beginner, Candy Alexander is your go-to source for simplifying aquaponics and fostering a sustainable gardening experience.