Have you ever wondered what it really means for your aquarium to be "cycled"?

This is referring to natures Nitrogen Cycle.
Here is a quick break down for a better understanding:

The Nitrogen Cycle is natures way of purifying itself.
It is the process in which nature creates beneficial bacteria to break down waste.
Just as in nature, an aquarium environment needs to develop a Nitrogen Cycle as well.
This cycle will be what converts the toxic fish waste (fish excreta, urine, and old food) into a non toxic form and is what will keep your aquarium environment clean and healthy.
This a lengthy process and takes much patience.

Just What Does The Nitrogen Cycle Do Inside an Aquarium Environment?

The Nitrogen Cycle has 3 major steps inside an aquarium environment.
When testing the Nitrogen cycle with water test kits, we are reading the byproducts of the Nitrogen Cycle.
These byproducts are ammonia, nitrite, and nitrate.

Step #1: Ammonia (the byproduct of fish waste)
Fish excreta, urine, and old food pollute aquarium water. The decaying process of this waste creates ammonia which is very toxic to fish.

Step #2: Nitrite (the byproduct of Nitrosomonas Bacteria)
Nature creates a beneficial bacteria called Nitrosomonas Bacteria to break down the ammonia. The converted byproduct of this bacteria is called Nitrite which is still toxic to fish.

Step #3: Nitrate (the byproduct of Nitrobacter Bacteria)
Nature creates a beneficial bacteria called Nitrobacter Bacteria to break down the nitrite. The converted byproduct of this bacteria is called Nitrate which is not toxic to fish if kept at low levels.

In nature, Nitrate byproducts happen to be a food source for plants and algae.
In an aquarium environment, we would not be able to keep enough plants to consume all the nitrate; therefor, we preform partial water changes to remove this byproduct before it reaches toxic levels.

So, the "cycle" moves like this:
fish waste = ammonia (toxic to fish)
Nitrosomonas Bacteria = nitrite (toxic to fish)
Nitrobacter Bacteria = nitrate (not toxic to fish if maintained at low levels)
water change (to remove nitrate)

A "cycled" aquarium should read:
ammonia: 0ppm
nitrite: 0ppm
nitrate: ideal range .1ppm - 40ppm ,
Warning: nitrate levels should never exceed 75ppm - Exceeding this level is toxic to fish.

hennyxlb

how do you get things that measure nitrate levels?????

AKaeTrue

Aquarium water testing kits - they are sold at pet/fish stores.

ginjawarrior

i have a 30l aquarium with an intank filter/pump with venturi fiiting for airieation with heater and single tube for light. i put several elodea in and a few broadleaf plant's in (not sure which) i left tank for about 4 days then i introduced 6 guppies into tank. i was doing daily water changes for a week or so but then wasnt about for 3 days when i returned 4 guppies had died. i imediatly did a large water change but unfortunatly another died that evening. i continued doing alot of small water changes spread over the day for next few days but sadly found the last one dead this morning.
now im guessing after reading up that tank hadnt had chance to cycle yet.... but what i wanted to know was do i leave tank and water as it is now to continue cycling? or do i clean it all out and try starting from scratch?