What is Cycling and why do I have to cycle the aquarium?
Cycling the aquarium it is the most important thing you should know but unfortunately cycling it is ignored by most beginners. An uncycled aquarium in most cases will kill your fish so before you put the fishes in tank you must assure that you have a cycled aquarium. On internet you will find many names for cycling as nitrogen cycle, startup cycle, biological cycle or nitrification.
From what I noticed is that beginners buy in the same day the tank and fishes and insert the fishes into the aquarium in the same day, sometimes beginners use some “miracle solutions” that say: fish can be introduced immediately into aquarium.
Aquarium cycling it is in fact the nitrogen cycle and in your aquarium manifests as in nature, the only difference is that in nature the volume of water is huge and the bacterial colonies existed for billions of years.
In you aquarium the nitrogen it is produced by fish, food or dying plants and because an aquarium it is a closed system you do not have how to eliminate the nitrogen from your aquarium, in time nitrogen will be transformed into ammonia (NH3/NH4) which is very toxic for fish.
The ammonia (NH3/NH4) it is transformed into nitrite by the nitrosomonas bacteria but in a new aquarium the main problem it is that nitrosomonas bacteria has not been developed yet and takes time till start to develop. Nitrite (NO2) it is less toxic than nitrogen but for values of 0.3mg/l it is dangerous for fish, and usually if that value it is exceeded your fish will die.
The next step into the aquarium cycling it is the conversion of nitrites into nitrates (NO3), this step it is done by the Nitrobacter bacteria which uses oxygen to transform NO2 into NO3.
Nitrates are not so toxic for fish but high value of NO3 will reduce the fish lifetime, the main key for high values of NO3 is that the rise of NO3 to take in time in this way fishes will adapt to higher values of NO3.
In a planted aquarium the nitrates (NO3) will be used by plants like nutrients, to maintain a balance of NO3 you must have a balance between fish and plants because for example a plant it is not capable to use the full amount of NO3 produced by 50 fishes.
What is the maximum level of nitrates (NO3) for a tropical tank?
In a tropical tank the maximum level it is 50mg/l, this value must be adjusted if you have sensitive fish like Discus, from my experience a value of 20mg/l it is very good for a freshwater tank.
How Long Does It Take For A Fresh Water Fish Tank To Cycle?
After I present the aquarium cycle to a beginner I receive the question How Long Does It Take For A Fresh Water Fish Tank To Cycle?
Generally it takes from 4 to 6 weeks, in this time it is not recommended to add fish in tank. It is recommended to add bacterial cultures which will help you in cycling the tank, I recommend Prodibio Biodigest because it has billions of bacteria.
Some aquarists squeeze a sponge from an old filter hoping that they will help the cycling in this way but from my point of view doing something like this will do more harm to your aquarium because it will bring all algae from that tank and because your tank it is new you will not have how to fight with those algae, of course you will say “that tank looks very nice and it is without algae” but you have to remember that tank is very stable.
Even after 4-6 weeks since you started to cycle the aquarium you do not have to hurry to put many fish into tank, first put few fish in tank and in time add more.
Aquarium Cycling can be affected by the next aspects:
- Adding to many fish
- Changing too much water, especially tap water because contains chlorine which destroys bacterial colonies
- Cleaning the filter sponge with tap water, it is a must to clean the filter`s sponge only with water from aquarium.
- Stopping the filter for many hours
The best thing you can do it is to keep alive the bacterial colonies because those small bacteria will help you to have a stunning tank.
To see if your tank is cycled you will have to measure the values of NH3/NH4, NO2 and NO3.