There is one thing that holds very high importance but is, unfortunately, the least understood in Aquaponics and that is the bacteria we depend on as well as its main function in the nitrogen cycle. I can guess what you are probably thinking, you’re probably thinking bacteria or some people refer to it as “germs” as what they hear from most disinfectant commercials are bad, but are they really? The truth of the matter is, in life and in everything there are always aspects that are considered good and there are aspects that are seen as bad and yes that includes bacteria. Life would not be life without them. Fish in general releases ammonia. Ammonia excreted by fish in an ocean or in a lake won’t affect it at all because of the massive volumes of water that can dilute the ammonia. But if you are keeping fish in your house you have to learn to manage ammonia levels since this can be very harmful to your fish. When food is decomposed it also creates ammonia. What happens if you have excess ammonia in your system?
The effects of too much ammonia are as follows:
- Impaired growth
- Severe damage to the tissues of fish especially to the kidneys and their gills
- Death
- Reduced resistance to disease
The good news is that nature has already taken care of this problem through Nitrosomonas sp. Nitrosomonas sp is a good bacterium that consumes ammonia and converts it into nitrite. Nitrite compared to ammonia is less toxic to your fish but it’s still not a good thing. This is because nitrite stops your fish from taking in oxygen but not to worry because again, nature has already taken care of this problem as well with the help of your Nitrobacter sp. Nitrobacter sp is a good bacterium that consumes nitrite and converts it into nitrate. And as luck would have it, nitrate is a favored food among plants. And what’s more, is that fish are able to tolerate high levels of nitrate than with ammonia or nitrite. What you have just read is what we would like to call as the nitrogen cycle.
If your Aquaponics system has the right amounts of this type of bacteria that can process ammonia and nitrites it is believed to have cycled. Your principal goal is to establish your nitrogen cycle as fast as you can and with less stress as possible on any marine life that you may currently have. If these bacteria do not have their corresponding foods then they won’t exist in valuable numbers.
This is the reason why you will usually see an ammonia spike whenever you set up a new tank. The bacteria in a new tank will reproduce; in other words, they will increase in numbers as a response to the increase in ammonia load. So this would explain why you would normally see an ammonia spike before they get to respond. After you have ammonia your bacteria will start multiplying. The same principle applies to Nitrobacter sp. These bacteria will only start working as soon as the Nitrosomonas sp is already comfortable and produces a lot of nitrites. Nitrosomonas sp will not process ammonia unless the pH level is at 6.0 or less; this was discovered in a sterile lab culture. Another research similar to this discovered that species of Nitrosomonas sp. in a natural environment like soil are still able to process ammonia even at a pH of 4.0.
A lot of people who have Aquaponics systems strive to maintain their pH level between 7.0 and 7.2 because at this range their bacteria, fish, and plants are already satisfied. The nitrogen cycle has the propensity to decrease pH level but it is relatively easy to keep a pH of 7 by adding calcium carbonate to your system. Calcium carbonate can help increase your pH but it will stop dissolving if your pH reaches 7.4, this means that the pH level will maintain its stability until all the available calcium carbonate is used up.
They have to colonize a surface whether synthetic biomedia, sand or gravel to achieve optimum growth. (Click here to learn about Techniques Use To Run An Aquaponics System)