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March 30, 2020 | By Eric Nadon

Part 1: Nitrification Additives

While some aquarium keepers think water conditioners are unnecessary, they often experience aquarium water quality and other related problems as a result. In fact, one of the most common problems that many new aquarium owners face is that of toxic ammonia and nitrite levels, both of which can result in catastrophic fish loss. Had these individuals started their aquariums with a few small, hardy fish, controlled feeding, and added Fluval Cycle Biological Enhancer, ammonia and nitrite would have been efficiently controlled and eliminated.

Despite our best efforts to provide the correct information to fishkeepers around the world, we continue to hear of these easily-avoidable events. The following is a list of the most common myths related to aquarium water quality and the use of water care products.

Myth 1: You don’t need biological supplements because nitrifying bacteria naturally exist and will develop within your aquarium.

While it is true that nitrifying bacteria do naturally exist – the various species of bacteria present in Fluval Cycle Biological Enhancer are naturally sourced – these bacteria are usually not found in tap water. These efficient nitrifyers were originally sourced from a variety of natural environments (harsh, fluctuating environments are most common, as strong, resistant strains of bacteria are preferred) and are certainly not found in any quantity in municipal water treatment facilities that utilize high levels of potent oxidizers such as chlorine. Some water treatment plants, depending on the local water chemistry, also use hydroxides to increase the pH value of the water and to control the oxidation and degradation of pipe networks: this further reduces the chances of any beneficial bacteria existing in tap water.

Myth 2: Once your new aquarium has cycled, using a biological product with nitrifyers is pointless and just a waste of money.

While the initial cycling of an aquarium is the most critical time in terms of the potential development of toxic levels of ammonia and nitrite, the fact of the matter is that nitrification is a constant, ongoing process in aquariums. The nitrogen introduced into an aquarium on a daily basis (typically in the form of fish food) is always cycled through by these key bacteria species from ammonia to nitrite and then to nitrate. If these nitrogen compounds are not processed and are left to accumulate, they will stress fish and make them vulnerable to a variety of diseases and conditions that can cause harm, or simply kill them.

Once fish consume fish food, they excrete organic waste which is subsequently converted into ammonia, a toxic nitrogen compound. If a healthy population of nitrifying bacteria is established in the aquarium, this ammonia will efficiently be converted first into nitrite and then into nitrate. To witness this ongoing process in a mature, cycled aquarium, test a well-stocked aquarium shortly after a good-sized feeding: you will likely measure some ammonia and nitrite. Later, however, both of these tests will read zero, indicating that the nitrifying bacteria are doing their jobs effectively.

The bacterial world is a carnivorous one: different species of bacteria predate each other, and as such the species responsible for nitrification in an aquarium can quickly be reduced and replaced by less efficient species. The concept is known as the competitive exclusion principle: two or more species competing for the same limited resource cannot coexist at constant population values – complete competitors cannot coexist. Regular dosing of a high quality biological supplement such as Fluval Cycle Biological Enhancer is thus crucially important to ensure an optimum mix of the best nitrifying strains of bacteria is always present in an aquarium. Additionally, regular dosing also helps desirable, efficient nitrifying bacteria to competitively exclude undesirable pathogenic bacteria and can help avoid disease issues with fish.


Myth 3: Biological products are ineffective: they cannot contain live bacteria due to the lack of oxygen and food in the bottle.

This is a common, yet entirely incorrect statement about well-researched products such as Fluval Cycle Biological Enhancer, which has over 25 years of product evolution behind it. Fluval utilizes a special process prior to bottling which causes the nitrifying bacteria to enter into a dormant state. As these bacteria are slowly exposed to specific environmental conditions, they naturally construct a protective bio-film. You can see these protective bio-films in Fluval Cycle Biological Enhancer: they are the opaque to beige colored flocs which accumulate at the bottom of the bottle. Shaking the bottle before use is thus important, as this ensures the nitrifying bacteria are uniformly introduced into the aquarium with every dose.

The formation of bio-films by bacteria is a protective survival strategy, used in response to the specific environmental conditions they are exposed to. Thus, oxygen and food needed to maintain bacteria in this state is very minimal. Once the bacteria are introduced into the aquarium, they emerge from their dormant state, and begin consuming nutrients and resources normally. Fluval Cycle Biological Enhancer also features a best before date: if used before this date, you can be sure you will always get the expected nitrification performance from the 500mg/L of biomass included in every bottle.

Myth 4: Biological supplements can contain anoxic bacteria, which are harmful to your aquarium’s inhabitants.

Bottles containing biological supplements are sealed, and as such contain little to no oxygen. Thus, it is sometimes assumed that the contents will at some point become anoxic. This is easily disproven, however, by simply opening the bottle and smelling its contents: if they had become anoxic, you would know from the foul smell! Although it is possible that lower-quality products could potentially become anoxic over time, Fluval Cycle Biological Enhancer is clean, pure, and carefully produced. The bacteria are raised and bottled in controlled conditions to ensure the purity of product and the exclusion of contaminants. As such, there is no risk of it containing any harmful, anoxic bacteria.

In addition to the water quality benefits discussed above, regularly dosing Fluval Cycle Biological Enhancer can provide a source of food for baby shrimp and fish. Bio-flocs are a great first food source for shrimplets, while small fish fry can consume the various species of bacteria when they first hatch.

In summary, the use of Fluval Cycle Biological Enhancer is recommended in the following situations:

  • New aquarium cycling: follow new aquarium dosing instructions on label
  • Regular weekly use
  • After filter maintenance: filter media cleaning and/or replacement
  • After medicating: before dosing, ensure any remaining medication is removed via partial water changes and activated carbon
  • When adding new fish: helps to avoid ammonia spikes that can be created when adding to the existing fish population


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