Bacterial Bloom During Cycle For Aquaponics

Last Updated on July 26, 2021 by Marco C.

Bacterial bloom during cycling establishes the necessary bacteria for nitrogen fixation and processing the fish waste for plants to utilize. Cycling starts with the initial introduction of nitrogen into the system in the form of ammonia or urea from fish. This attracts the necessary bacteria for the nitrogen cycle to start. Bacterial bloom in an established tank requires necessary conditions to be able to support the nitrogen-fixing bacteria. This article will discuss the bacterial bloom during cycling and how to initiate the nitrogen cycle in your aquaponics system.

Bacterial Bloom During Cycling Begins With The Introduction Of Nitrogen From Your Fish Or Ammonia

There are different enzymes and bacteria necessary for the complete cycling of nitrogen in your aquaponics system. The first step for the nitrogen cycle begins with your urea from the fish. Urea then breaks down into ammonia and carbon dioxide through the enzyme urease. This ammonia will attract the nitrogen-fixing bacteria called nitrosomonas. Nitrosomonas will convert the ammonia in your water into nitrites. Both ammonia and nitrites are dangerous for your fish and will need another step to be available for plants. The presence of nitrites will then attract nitrobacter, which convert nitrites into the bioavailable nitrates for your plants. Nitrates are the form we are after for aquaponics. They are not toxic for fish and available for plant uptake. Your fish tank’s nitrogen cycle happens thanks to these bacteria, so it is essential to establish them with cycling.

A Biofilter Is Essential In Establishing and Housing Bacterial Bloom Of Beneficial Bacteria

A biofilter includes the housing of necessary bacteria for nitrogen fixation. To make your biofilter to house the nitrogen-fixing bacteria, purchase bio-balls from your local aquarium or pet store. Bio balls provide the necessary surface area for nitrogen-fixing bacteria to latch on to and establish themselves. There are different available bioballs in pet stores which differ in surface area for which bacteria can be housed. More surface area from your bio balls will allow more of the nitrogen-fixing bacteria to establish. In general, your biofilter must be 15% to 20% of your fish tank’s water volume. Standard bioball specific surface area has a minimum of 91.44 square foot per cubic foot.

 Housing Bacterial

Media beds can also double as a biofilter for your system. Different media have their own specific surface area available for nitrogen-fixing bacteria to establish. Depending on the media, you will have to adjust the size of the media bed. For media beds using gravel as a biofilter, it will be best to have a ratio of 1 fish tank volume: 1 media bed volume.

Naturally, Start Your Nitrogen Cycle With The Introduction Of Fish

First way to begin your bacterial bloom for the fish tank during initial cycle is to introduce a small amount of fish. The fish will produce feces which contain urea to kick start your nitrogen cycle. Only introduce a small amount of fish, so as to avoid build-up of ammonia and bacterial bloom of pathogenic bacteria. A new system can not convert the full load of urea and ammonia from fish excrement to nitrates and ammonium. Personally, I begin my systems with having just one fish initially until the initial cycle for bacterial bloom finishes. This ensures that as nitrogen input from fish population increases, the necessary bacteria is present to convert the nitrogen fully.

Use Water From Established Aquaculture, Aquaponics, Or Natural Bodies Of Water

Introduce bacterial bloom in your fish tank by using water from healthy ecosystems. Ensure that the ecosystem, aquaculture tank, or aquaponics system is free from pathogens so as not to infect your system beforehand. A bottle full of water from any of the sources will introduce the necessary bacteria to establish your nitrogen cycle. After 24 hours, you can start to introduce either a small amount of fish or a small amount of household ammonia. These will feed your bacteria until they have established themselves in the biofilter. According to the UN-FAO, depending on climate and water quality, initial cycling can take anywhere from 1 week to 6 weeks.

Introduce Ammonia Into Your Biofilter To Establish The Nitrogen-fixing Bacteria In Your Fish Tank

Introducing ammonia to start the nitrogen fixation in your tank also causes bacterial bloom. As ammonia is not usable by plants and is still toxic to fish, it is best to introduce ammonia in small amounts and without fish in the system yet. Ammonia will not be immediately fixed by the bacteria as it will take time for the nitrogen-fixing bacteria population to establish itself. As ammonia attracts the necessary bacteria for conversion, nitrite concentration will increase as well. In the presence of nitrite, nitrobacter will begin to populate your biofilter.

Other Causes Of Bacterial Bloom Could Be Excessive Nitrogen From Overfeeding Or Restarting Your Biofilter

Although the bacterial bloom itself is not dangerous for your fish and plants, it is an indicator of nutrient imbalance. Excessive nitrogen from overfeeding could cause an increase in ammonia and nitrites which will harm your fish tank. The bacteria multiplies in the presence of too much ammonia and nitrites as their food causing white cloudy water. Limit the amount of fish feed to 1% to 2% of total fish biomass to avoid excessive feeding.

Another reason for bacterial bloom in your fish tank is the replacement or failure of your biofilter. When the biofilter is removed, this will decrease the population of nitrogen-fixing bacteria. Immediately replace or replenish your biofilter when this happens.

Bacterial bloom during initial cycle naturally occurs as your system’s nitrogen-fixing bacteria population establishes itself. Although the bacteria will not harm your fish population, it indicates that your system has not established it’s nitrogen cycle yet. Without an established nitrogen cycle, your system can not convert the toxic forms of nitrogen into useful nitrates or ammonium for plants to uptake. Time will solve the problem of cloudy water from bacterial bloom by itself. This makes the biofilter an essential part of your system which is mostly overlooked by new practitioners. Nitrogen-fixing bacteria are essential for completing your aquaponics system’s nitrogen cycle. Without the nitrogen-fixing bacteria, you will have an excessive amount of ammonia and nitrite which are not available for your plants.

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