Getting Started, cycling your tank.

The following describes the chemistry changes that occus in your new aquarium
before it balances naturally. Fish will be stressed and delicate ones may die if put into the aquarium
before balance is reached. To start the tank cyclying, use cheap, hardy fish because they are best suited
for the demanding task. (Click on the cheap hardy fish link if you want to learn more about them.)

Day 1
Some people set up the tank and leave it for a week before putting the fish.
However, the result will be the same as putting the tank 1-2 days because
this practice only removes chlorine from tapwater and nothing else.
The tank will NOT cycle without any ammonia in the water.

To add ammonia to the water, cheap hardy fish should be introduced.
Anywhere from two to five inches of fish may be used per ten gallons of water
(any less and the tank may go through another, but lesser, cycle when more fish are added
in future; any more and the water condition may go beyond what the hardy fish can tolerate).
In the first day, with the introduction of the cheap, hardy fish, there should
not be enough ammonia produced to be measured. Therefore,
All readings should be near zero.

Day 2
Feed the fish as usual, but do not overfeed. This is because overfeeding can
cause the water to be overly polluted. We don't want to worsen the already
poor water quality, especially in later stages of the cycle.
Remember that during cycling, we try not to
change the water because we don't want to prolong the time it takes
for the tank to cycle. If changing water is absolutely necessary, keep the water
changes small and less than 20% of the total water volume.

Important!: Used aged water or dechlorinated water only! The smallest amount
of chlorine will set you back in the cycle, especially in the beginning stages where
beneficial bacteria is still in minute quantities.
Ammonia should be rising to a measurable amount.

Day 3
Ammonia rises quickly to almost dangerous levels. You should see a spike in the
ammonia level if you are actively testing the water.
The fish in the tank should show signs of stress due to the water condition.
During this period, be careful not to feed too much because the fish
may lose their appetite. Put a little food at a time and only put more if the
food is finished. Also, control the amount the fish eats.
You should not always feed until the fish won't eat anymore.
It is generally better to keep the fish a little hungry. Especially
when feeding dry pellet foods, a fish may become overfull when the food
absorbs water and expands in the stomach.
It is better to feed a more small meals than less big meals.
First stage bacteria are consumming ammonia and converting them into nitrite.
However, as the bacteria is still very little, only a very small amount of ammonia is
being converted into nitrite. As the ammonia being consumed is less than the ammonia
the fish is producing, ammonia levels in the tank continues to rise, however, at a slower rate.
First stage bacteria are growing to become established,
but the amount is still very low.
Nitrite level in low, unmeasurable quantity.

Day 5
Ammonia level maxs out and starts dropping. This is because the first stage bacteria has
grown in quantity to be able to consume ammonia and converts them to nitrite
faster than the fish can produce them. The result is a drop in ammonia level and rise in nitrite level.

During this time of maximum ammonia, less hardy fish may die. If you observe your fish
having difficultly coping, you may want to change some water in the tank so ammonia is more diluted.
As warned earlier, used aged water or dechlorinated water only!
Don't change the water if not absolutely necessary.
Ammonia maxs and drops.
Nitrite levels rising.

Day 8
First stage bacteria are well established.
Ammonia level drops at a faster and faster rate and finally to zero.
Nitrite levels begin to rise faster than before.
During this time when the ammonia drops rapidly to zero, you will notice
the fish becoming active and happy, looking for food, fighting, perking up.
This is because this is their first break from the stressful "work" in the last few days.
First stage bacteria well established.
Temporary improvement of water condition.

Day 14
Nitrite levels has climbed to reach the maximum levels.
Again, fish in the tank will start to show stress.
During this time, partial water changes can be made but I don't need to tell you now,
change less than 20% and use de-chlorinated water only.
Nitrite levels maxs.

Day 27
During the last few days, second stage bacteria grows as they consume the nitrite and converts
nitrite into nitrate. Nitrite levels continue to be elevated for several weeks.
Nitrite being converted to nitrate by second stage bacteria.

Day 29
Second stage bacteria are well established.
These second stage bacteria are able to convert nitrite as fast as they
are produced. Nitrate levels now becomes measurable.
Second stage bacteria well established.
Nitrate levels rises.

Day 30
Both first and second stage bacteria are now well established.
Ammonia produced by fish is converted into nitrite and then nitrate with no excess
because there are now enough fisrt and second stage bacteria to process them.
Congratulations! Your tank is cycled and ready for your fish to be put in!
Tank is cycled.

additional notes:
A rise in nitrate levels after the tank has cycled may cause an algae bloom.
This is because nitrate is a plant nutrient. To prevent excess algae, you
may want to put in some water plants to absorb and use the nitrates as they are produced
by second stage bacteria. This effectively starves the algae of the nutrients they require,
bringing them under control. Also, you will have happy plants!

If you want to use do a cycle without fish, then this fishless cycle article may be useful.

You may also which to view other freshwater articles.

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