Cycling is an important concept when developing your aquaponic system. It initiates the Nitrogen Cycle within your closed ecosystem. Th Nitrogen cycle develops a natural “bio-filter”, creating the proper balance of beneficial bacteria so that your plants and fish can prosper. A great reference book for Aquaponics is simply called “Aquaponic Gardening” by Sylvia Bernstein. She goes into great detail about all the topics we cover here.
When we talk about Cycling the key components involved are, Ammonia, Nitrites and Nitrates. Before we delve more into cycling we want to mention how important water quality is. Always check on your water quality before adding any to your system. If you need more information on that before we begin with cycling go back to our tab labeled “Water Quality” under the menu bar “What is Aquaponics”.
There are a couple of different ways to “Cycle” your Aquaponic System; you can either cycle without fish or with fish. Here we will discuss both methods and let you choose what works best for your particular situation.
CYCLING WITHOUT FISH
Cycling without fish is a great, safe way to go. It puts minimal stress on your fish and is a fairly controlled way to develop your systems Nitrogen cycle. Although, when using this method versus cycling with fish you do have to purchase some form of Ammonia. Your system needs a form of ammonia in order to kick start the Nitrogen cycle which converts ammonia into Nitrites then usable Nitrates. Another benefit of cycling without fish is that you do not have to worry about elevated ammonia levels because there are no fish in the system that can be harmed by the Ammonia.
1) Start by adding plants into your media beds. Hold off on adding any plants in your DWC or NFT section of your garden. Your media bed plants will most likely not be thriving 100% within the first couple weeks but know that once cycling is complete and nitrates are available they will prosper again.
2) Next start adding Ammonia. There are several different ways to add ammonia;
-The first and most obvious is to find Liquid Ammonia that is pure and 100% ammonia. If it has any perfumes, dyes, soaps or surfactants avoid this kind. It is a sign that it has some form of additive if you shake the bottle and you see foam. Sometimes 100% ammonia can be hard to find but we have had good luck ordering it online or we have also heard that sometimes you can find it at your local hardware store.
-Another source of ammonia is Ammonium Chloride (crystallized ammonia). This is very similar to liquid ammonia but it comes in a dry powdered form. It can be found at your local aquarium store or online.
3) Now that you have decided the form of Ammonia you want to use start to slowly add it into your system. The amount you use will obviously vary tremendously depending on the size of your system but you are shooting for an ammonia reading of 2-4PPM to start. We normally start by adding a 1/2 cup of ammonia to a medium sized setup. Be sure to take note of the proper amount of ammonia for your personal setup and continue to add that amount daily. Once Nitrites appear (hopefully within a few days) decrease the amount of ammonia you are using by half.
4) Next we need to give your system an extra boost into the nitrogen cycle. While you are continuing to add small amounts ammonia daily you also need to provide some form of bacteria to start. This can be found by taking media from a friends aquaponic system, or even aquarium. Make sure the media that you take is from a clean, disease free environment. You can also purchase an inoculant called Pro Line Nitrifying bacteria from aquatic ecosystems.
5) Continue to add a small amount of ammonia daily while closely monitoring your Nitrites. If your nitrite levels exceed 5PPM stop adding ammonia. Shortly after this Nitrates should appear. Once Nitrate levels reach 5-10 PPM and the ammonia and nitrite levels have gone down to zero it is now completely safe to add your fish.
6) At this time you can also add plants into your DWC or NFT portions of your garden.
7) Continue to closely monitor Ammonia, Nitrite, Nitrate and pH levels for the first couple of months that you have your new system. Know that while your system is still maturing growth rates will begin to slightly change. As time goes on and your setup develops a broader and larger ecosystem the growth of your plants has the potential to slightly increase.
CYCLING WITH FISH
The benefit of cycling with fish is that they provide the ammonia for you through their waste instead of you having to add it yourself or wait an average of 8 weeks for it to naturally become present. There is a slight risk involved in this method because you are placing your fish into a developing ecosystem that has high levels of Ammonia when you first start. If Ammonia levels climb to 3PPM or higher they can be toxic to your fish. This method can be somewhat stressful on your new fish but it is still very effective. If you choose to cycle with fish start with step one;
1) Start by planting your media grow beds. If you have a DWC or NFT section of your Aquaponic garden wait to plant these areas until Nitrates appear. Your media bed plants will most likely not be thriving 100% within the first couple weeks but know that once cycling is complete and nitrates are available they will prosper again.
2) Next add about 1/3 of your allowable stocking density to your fish tank. Waiting to stock to full capacity gives you more control over the amount of Ammonia you have in your tank. (Most Aquaponic gardeners recommend an average of 1 pound of fish per 5 gallons of water)
3) Do not feed your fish for the first few days of cycling. Feeding the fish creates more waste which creates more Ammonia. During this time due to transportation and being in a new environment your fish will be somewhat in shock and not want to eat during this time anyways. Once Nitrates appear and your ammonia and nitrite levels are very low you can slowly begin to feed the fish.
4) Begin testing for Ammonia on a daily basis. Once it is around 1.0-1.5 PPM we recommend adding some form of bacteria. This bacteria can be a store bought Inoculant or you can take some media from a friends mature Aquaponic system. Green Acre Aquaponics recommends a store bought inoculant that is called ProLine Nitrifying Bacteria from Aquatic Ecosystems. If you choose to use an existing systems bacteria make sure that the system is free from any diseases that could potentially be transferred to your own system.
5) Continue testing Ammonia and Nitrites on a daily basis as well as checking for dead or suffering fish. Dead fish will off gas a lot of Ammonia which can be toxic to your other fish. (P.S. In the somewhat likely event that you have a fish die make sure to bury it in your soil garden, it is very beneficial to the soil)
6) The “safe” range for Ammonia is less then 3PPM and the safe range for Nitrites is considered less then 5PPM. Ideally when you are done cycling these rates will be at zero PPM. If either of these exceed their safe range you can do a water change to dilute the amount of Ammonia or Nitrites. You can safely remove about 1/3 of your water but make sure that you replace it with water similar in temperature and pH.
7) Once Nitrites and Ammonia are measured at very low rates (as close to zero as possible), the Nitrates begin to appear. This means that the nitrogen cycle is working. Nitrates are what your plants love and will prosper from.
8) Now that your nitrogen cycle is progressing you can add the remaining 2/3 of your fish. If you have a DWC or NFT section in your garden now is the time to plant them as well.
9) Continue to closely monitor Ammonia, Nitrite, Nitrate and pH levels for the first couple of months that you have your new system. Know that while your system is still maturing growth rates will begin to slightly change. As time goes on and your setup develops a broader and larger ecosystem the growth of your plants has the potential to slightly increase.
Note: Whether you are cycling with fish or without you add plants at the same time. Know that the plants probably will not grow a lot with in the first few weeks while the nitrates are still developing. If you want to give them an added boost we recommend using an organic liquid seaweed product. This helps support your plants in the beginning stages and will not harm your fish.