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Nitrogen Cycle in Aquariums
Last updated on November 17th, 2023
Nitrogen Cycle in Aquariums
First things first. Before learning how to cycle a saltwater tank, it is important to understand what the nitrogen cycle in an aquarium entails. Beyond just what the aquarium nitrogen cycle is, you need to know why it is important. Then I will show you how to cycle your tank the right way. Lets dive in and learn about the Aquarium Nitrogen Cycle.
What is the Nitrogen Cycle in Aquariums
Creation of Ammonia
The nitrogen cycle in aquariums is the process that starts with decaying organics such as over-feeding or dead fish or other creatures. As these organic compounds decay, they break down adding ammonia to the aquarium. Ammonia, a molecule made up of Nitrogen and Hydrogen, is toxic to fish and other aquarium life.
Nitrosomonas - Converting Ammonia to Nitrite
The next step of the nitrogen cycle in aquariums relies on nitrosomonas. This ammonia-oxidizing bacteria utilizes ammonia as a source of energy, and carbon dioxide (CO2) as a carbon source. This beneficial bacteria then creates the less toxic nitrite. Though still toxic, nitrite is significantly less toxic than ammonia.
Nitrobacter - Converting Nitrite to Nitrate
The second beneficial bacteria involved with the nitrate cycle in aquariums is Nitrobacter. This chemoautotrophic bacteria are known for oxidizing nitrites into nitrates. Nitrates are minimally toxic in the reef. Though large amounts of nitrates may cause problems for certain species of reef life, the majority of reef life can withstand the quantities generally found within the reef tank.
Nitrate Removal - The Nitrogen Cycle in Aquariums Continues
A key component that most articles and videos miss is that this truly is a cycle, and does not end with nitrates. Nitrates can be removed in a number of ways, including water changes. However, as part of the aquarium nitrogen cycle, nitrate is naturally consumed by algae in order to grow. This can take the form of nuisance algae such as hair algae, macroalgae such as chaetomorpha, or even contained algae growth such as that found in an algae scrubber.
The algae that grows in the aquarium, or in the ocean, is then consumed by the fish and reef life. Which ten produce waste that starts the cycle all over again. In the reef tank, some of these algae can be removed by hand in order to remove the nitrates from the aquarium before they contribute to the cycle again.
The Nitrogen Cycle NEVER Ends
Though we often consider a tank to be ready for fish after the nitrogen cycle is complete, this is not really the case. Cycling a reef tank is really the process of building the nitrosomonas and nitrobacter beneficial bacterias. During this time, the nitrogen cycle is noticeable as the colonies of bacteria grow. That being said, the cycle is always happening within the aquarium. The bacteria is generally so efficient that you simply will never be able to measure ammonia and nitrite because they are converted so quickly.
This short video from Marine Depot provides additional information about the Nitrogen Cycle in Aquariums.
How to Cycle a Saltwater Tank - Starting the Nitrogen Cycle in your Aquarium
To start the Nitrogen Cycle in your Aquarium, you need to provide a source of ammonia to the aquarium. There are a number of ways to start the nitrogen cycle in your tank. The main ways to start the cycle include adding a fish (NOT RECOMMENDED), "Ghost Feeding", or even adding chemicals such as ammonia chloride. Combined with enough surface area for the bacteria to grow, an a little patience, most of these are recipes for success.
If you are looking for more information about How To Cycle a Saltwater Fish Tank, see the complete guide linked below!
How To Cycle a Saltwater Fish Tank
How Long Should A Tank Cycle
The cycling process can be as short as a few weeks, or as long as a few months. It's important to be patient during this process because you are building up beneficial bacteria colonies in your tank. If this is rushed, you may find ammonia and/or nitrite spikes occur later on. Leading to death of marine life.
Make sure to measure ammonia, nitrite, and nitrate frequently to watch the rise and fall of ammonia and nitrites. When you are to the point of both of these reaching 0, and nitrates are rising, the cycle is complete. At this point, you can start to do water changes and make sure your refugium is well stocked with chaeto or other macroalgae to lower the nitrate levels. The goal is to reduce the nitrate levels to a value under 20ppm before adding fish.
Remember that adding more life to the tank will always introduce more ammonia and you may see small cycle-like spikes when adding to your aquarium. This is normal. As long as you measure and track these values to ensure a large spike is not occurring, you should be okay.
Recommended Ammonia, Nitrite, and Nitrate Test Kits
- Saliftert Nitrate Test Kit
- Saliftert Nitrite Test Kit
- Saliftert Ammonia Test Kit
- Red Sea Marine Care Test Kit (Nitrate, Nitrite, Ammonia, pH, and Alkalinity)
Reef Tank Nitrogen: Understanding Ammonia, Nitrite, and Nitrate in the Reef Tank
Get it On Amazon
Understanding the nitrogen cycle is crucial in setting up a saltwater aquarium, as well as maintaining one! This book will discuss ammonia, nitrite, and nitrate in saltwater aquariums as well as discuss the ever-going nitrogen cycle in reef tanks!
Learn how to know when your tank is cycled, as well as how ammonia, nitrite, and nitrate play a role in your saltwater aquarium. By knowing how they work, you can also learn how to reduce these nutrients!
Conclusion
In this article, we discussed the Nitrogen Cycle in aquariums. Focusing on what the nitrogen cycle is and how it works. We also covered how to start the cycle in a reef tank, and how long you should wait. If you're looking for more information about how to cycle a saltwater tank, I have a guide that covers this in much more detail below.
How To Cycle a Saltwater Fish Tank
About the Author
John Krenzer
John is a Software Engineer with a passion for saltwater aquariums, as well as the founder and president of Reef Stable. He started in the aquarium hobby as a child with a 20 gallon freshwater aquarium. His interest in aquarium life grew and in 2008, John set up his first saltwater aquarium.
Today, John maintains an over 300 gallon reef tank system, consisting of a 120g reef and a 210g reef. These large tanks are contained within the same system, sharing a sump as a means to reduce total maintenance and increase total water volume.
John writes articles for the blog as a means to learn about more reef aquarium topics. These articles act as a reference for the readers as well as himself. John updates these articles frequently to provide additional information or make corrections as new information becomes available.
If you would like to request an article, tank tour article, or to collaborate, let me know via the Contact Me Page!
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