How to Maintain an Aquarium's Nitrogen Cycle

Updated on May 22, 2019
Jana Louise Smit profile image

Jana worked in animal welfare with abused and unwanted pets. She loves sharing her hands-on experience regarding domestic and wild critters.

Source

Nitrogen Cycling in a Nutshell

Dealing with a nitrogen cycle is necessary for keeping an aquarium healthy. In order to do the best job, one must have a basic understanding of the following:

  • Where the nitrogen comes from
  • The chemistry of the cycle (we'll keep it short and sweet)
  • The role of beneficial bacteria
  • How to condition the tank with bacteria (very easy)
  • How to speed up conditioning
  • Why pH testing is a chore that's here to stay
  • How to correct unbalanced pH

Patience Is a Must

Many enthusiasts get bitten by the aquarium-bug when they stand in a pet store. Often this leads to impulse buys and dead fish. The latter results from something called “new tank syndrome.” This is basically incorrect water conditions that shock fish to death. To avoid this, one must knuckle the nitrogen cycle into a safe zone for fish and the bad news is that the process can take weeks.

Where the Nitrogen Originates

Not to be foul, but it starts with fish poop. For this reason, it is better to start small with “starter fish.” The intensity of the cycle is directly tied to the amount of waste expelled every day. Setting up a tank with a few hardy fish, like two or three guppies, will give them and the new owner a chance to condition the tank. Once settled, more fish can be added and monitored.

The Chemistry of the Cycle

  1. The fish answers nature's call
  2. The waste builds up as ammonia and carbon dioxide
  3. These chemicals are deadly in high amounts
  4. To remove them the tank must be conditioned with bacteria
  5. Beneficial bacteria break the ammonia down to less harmful nitrates
  6. The CO2 can be removed by plants, airstones, and filters
  7. Tests determine the water quality (pH)
  8. Corrective steps are taken if tests deem so necessary

Starter Stars

Guppies make excellent starter fish because they are remarkably tough and adaptable.
Guppies make excellent starter fish because they are remarkably tough and adaptable. | Source

The Role of Bacteria

Two kinds of bacteria condition the tank. When ammonia builds up, a species called “Nitrosomonas” breaks down ammonia into nitrites, which is a little less toxic. At a later stage, another bacteria called “Nitrobacter” convert the nitrites into an even less harmful substance; nitrates. Although nitrates can also be deadly in high concentrations. Deadly concentrations of nitrites and nitrates can be controlled through regular water changes.

Establishing a Bacterial Colony

Luckily, one needn't go out and buy these beneficial boogers. They are already in the water. However, in new aquariums, their numbers are too low to efficiently deal with waste. For this reason, you must take care of your growing bacterial colony and it's quite easy.

It takes about two weeks for your starter fish to kick off the ammonia levels necessary to interest the bacteria. They multiply rapidly to break down the dangerous chemicals. The first-phase bacteria, the Nitrosomonas, need plenty of oxygen to thrive. Make sure the aquarium is equipped with the necessary filtration and airstones to provide the oxygen the organisms need for healthy growth. This is all the second-phase bacteria, Nitrobacter, requires as well.

Speeding Things Up

This is completely optional. Some people just like to get their aquariums ready faster and there are several options available to them. Even so, conditioning times vary, depending on the size of the aquarium, water temperature and the number of starter fish. In general, it takes between four to six weeks.

  • Extra food. When uneaten fish food decays, it also adds to the ammonia of the tank. Be careful not to overdo it as a growing bacterial colony can only deal with so much ammonia
  • Mature gravel. This gravel comes from a tank where the nitrogen cycle and bacteria are well established (the donor aquarium must be disease-free)
  • There are commercial products available for this purpose, but generally, they don't speed up things that much
  • Gradually add a fish or two

Whether you go the slow or the fast route, at one point the water might develop a cloudy look. This is a healthy bloom of bacteria and the aquarium's filters should clear the water again within days.

Testing Water Quality

To keep fish healthy, the water must be tested on a regular basis. Available at pet stores or online, such kits test for pH, ammonia, nitrites, and nitrates. The first test should be done as soon as the tank is set up. During the conditioning phase, daily tests track the progress of the nitrogen cycle (note that it is normal for pH to drop at first). Once conditioning is complete, weekly tests are necessary for as long as the aquarium exists.

Depending on one's budget, pH test kits range from simple strips to electronic probes that give digital readings.
Depending on one's budget, pH test kits range from simple strips to electronic probes that give digital readings. | Source

Understanding pH

The pH scale shows how acidic or alkaline water is. At the bottom, 0 is considered highly acidic and 14 is highly alkaline. Neutral is marked by 7. The number one should aim for depends on the species of fish destined to occupy the aquarium once the tank has cycled.

The important thing to remember is that freshwater pH can rapidly shift and even a single point (say, a drop from 6 to 5) can be deadly. Once you know the pH values for your fish, aim to establish this number and do regular tests to keep it steady.

Correcting Unbalanced pH

The job of removing ammonia cannot entirely fall to bacteria. Frequent water changes are best to keep toxic chemicals under control. Aim for a five percent daily or fifteen percent weekly change.

When numbers show that your pH is too low, or acidic, try the following.

  • Some pH kits come with sodium bicarbonate, or baking soda, for this purpose. Follow the directions on how much to add
  • Do a water change

When numbers show that your pH is too high, or alkaline, try the following.

  • Some kits have sodium biphosphate for this purpose. Follow the instructions on how to use it safely
  • Add de-mineralized water

This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.

Questions & Answers

    © 2019 Jana Louise Smit

    Comments

      0 of 8192 characters used
      Post Comment

      No comments yet.

      working

      This website uses cookies

      As a user in the EEA, your approval is needed on a few things. To provide a better website experience, pethelpful.com uses cookies (and other similar technologies) and may collect, process, and share personal data. Please choose which areas of our service you consent to our doing so.

      For more information on managing or withdrawing consents and how we handle data, visit our Privacy Policy at: https://pethelpful.com/privacy-policy#gdpr

      Show Details
      Necessary
      HubPages Device IDThis is used to identify particular browsers or devices when the access the service, and is used for security reasons.
      LoginThis is necessary to sign in to the HubPages Service.
      Google RecaptchaThis is used to prevent bots and spam. (Privacy Policy)
      AkismetThis is used to detect comment spam. (Privacy Policy)
      HubPages Google AnalyticsThis is used to provide data on traffic to our website, all personally identifyable data is anonymized. (Privacy Policy)
      HubPages Traffic PixelThis is used to collect data on traffic to articles and other pages on our site. Unless you are signed in to a HubPages account, all personally identifiable information is anonymized.
      Amazon Web ServicesThis is a cloud services platform that we used to host our service. (Privacy Policy)
      CloudflareThis is a cloud CDN service that we use to efficiently deliver files required for our service to operate such as javascript, cascading style sheets, images, and videos. (Privacy Policy)
      Google Hosted LibrariesJavascript software libraries such as jQuery are loaded at endpoints on the googleapis.com or gstatic.com domains, for performance and efficiency reasons. (Privacy Policy)
      Features
      Google Custom SearchThis is feature allows you to search the site. (Privacy Policy)
      Google MapsSome articles have Google Maps embedded in them. (Privacy Policy)
      Google ChartsThis is used to display charts and graphs on articles and the author center. (Privacy Policy)
      Google AdSense Host APIThis service allows you to sign up for or associate a Google AdSense account with HubPages, so that you can earn money from ads on your articles. No data is shared unless you engage with this feature. (Privacy Policy)
      Google YouTubeSome articles have YouTube videos embedded in them. (Privacy Policy)
      VimeoSome articles have Vimeo videos embedded in them. (Privacy Policy)
      PaypalThis is used for a registered author who enrolls in the HubPages Earnings program and requests to be paid via PayPal. No data is shared with Paypal unless you engage with this feature. (Privacy Policy)
      Facebook LoginYou can use this to streamline signing up for, or signing in to your Hubpages account. No data is shared with Facebook unless you engage with this feature. (Privacy Policy)
      MavenThis supports the Maven widget and search functionality. (Privacy Policy)
      Marketing
      Google AdSenseThis is an ad network. (Privacy Policy)
      Google DoubleClickGoogle provides ad serving technology and runs an ad network. (Privacy Policy)
      Index ExchangeThis is an ad network. (Privacy Policy)
      SovrnThis is an ad network. (Privacy Policy)
      Facebook AdsThis is an ad network. (Privacy Policy)
      Amazon Unified Ad MarketplaceThis is an ad network. (Privacy Policy)
      AppNexusThis is an ad network. (Privacy Policy)
      OpenxThis is an ad network. (Privacy Policy)
      Rubicon ProjectThis is an ad network. (Privacy Policy)
      TripleLiftThis is an ad network. (Privacy Policy)
      Say MediaWe partner with Say Media to deliver ad campaigns on our sites. (Privacy Policy)
      Remarketing PixelsWe may use remarketing pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to advertise the HubPages Service to people that have visited our sites.
      Conversion Tracking PixelsWe may use conversion tracking pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to identify when an advertisement has successfully resulted in the desired action, such as signing up for the HubPages Service or publishing an article on the HubPages Service.
      Statistics
      Author Google AnalyticsThis is used to provide traffic data and reports to the authors of articles on the HubPages Service. (Privacy Policy)
      ComscoreComScore is a media measurement and analytics company providing marketing data and analytics to enterprises, media and advertising agencies, and publishers. Non-consent will result in ComScore only processing obfuscated personal data. (Privacy Policy)
      Amazon Tracking PixelSome articles display amazon products as part of the Amazon Affiliate program, this pixel provides traffic statistics for those products (Privacy Policy)
      ClickscoThis is a data management platform studying reader behavior (Privacy Policy)