The Aquarium Cycle
The most important step in setting up an
aquarium is knowing about the aquarium cycle to make sure that the nitrogen cycle is in full swing before you add your
fish
You need to cycle an aquarium to get the
nitrogen cycle working at the start.
Aquarium Cycling
When you first set up your aquarium it
will lack any of the nitrifying bacteria that are essential to maintaining water quality and it is only through
knowing how to go about cycling aquarium water that you can get the balance right. It will take time but is
probably the most important thing that you can do towards successful aquarium keeping.
The Aquarium cycle is simply the process
of setting up the aquarium so that it develops the nitrifying bacteria in the substrate and the filter and there
are two main ways of doing this.........with fish or without fish.
The Aquarium Cycle with
Fish
I am assuming that at this stage you have
already set up your tank, have it planted and have dealt with any chlorine in the water. Chlorine and
bacteria do not mix and your tank will not be able to cycle aquarium water if it has chlorine in
it.
You need to choose two or three
starter fish and add these to your newly set up tank. Start feeding them but
take care not to over feed them as this will cause problems. If in doubt about the amount of food watch
them eating to make sure that they are eating all the food that you put in the tank.
After a day or two you need to
test the water for an increase in Ammonia. It may be a few days until the
Ammonia levels have increased greatly but don't let them get too high. Under 0.25 is fine but anything
over that and you will need to do a partial water change to bring the Ammonia levels back
down.
As the biological filter starts you will
see nitrite levels increasing and ammonia levels decreasing as the Nitrosomonas(bacteria) start to grow and do
their work. Eventually you will see nitrate levels start to rise as the Nitrospira bacteria start to do
their job. Once your Ammonia and Nitrite levels are zero you have established a biological filter and are
ready to start adding extra fish.
But always a few at a time so as not to
overwhelm the biological filter.
The Fishless Aquarium
Cycle
There is a growing movement amongst
aquarists to cycle new aquariums using a fishless aquarium cycle.
Fish that are used for cycling an
aquarium will experience peaks in Ammonia and Nitrites and will suffer stress as a result. If you are
confident that you will be able to monitor Ammonia and Nitrite levels on a regular basis and react accordingly,
then you reduce the levels of stress for the fish and may feel confident that the fish will not
suffer.
If you have any doubts and would like to
cycle your tank without using starter fish then read on....
The aquarium cycle is exactly the same as
above but without the fish.
Rather than relying on the fish waste to
add ammonia you will be adding it through other means.
What you can do to add some ammonia and
start the process off is to add small amounts of fish food. This food will sink to the bottom of the
tank and start to decay causing ammonia to be formed. This in turn will cause the nitrifying bacteria
production that is needed. The whole process can take four to six weeks but don't be tempted to take any
short cuts as adding fish at this stage will simply cause ammonia and nitrite spikes and the distress to the fish
that you were trying to avoid.
Another method is to add a frozen prawn
in a nylon net to the tank. As the prawn decays it will add ammonia and start the aquarium cycle. For
someone who is trying to avoid fish suffering, it does seem bizarre to use a dead fish!!
The third method is to use household
ammonia. Make sure that it is unscented and then add Ammonia to the tank until you get a reading of about 4
ppm. This gives the conditions for the start of the aquarium cycle.
It is then a matter of monitoring the
Ammonia, Nitrite and Nitrate readings, topping up the ammonia occasionally. Once the Ammonia level returns to
zero within about twelve hours you know that you have enough nitrifying bacteria to support your fish
population.
Remember - Any kind of medication added
to the tank can destroy the biological filter. If this happens the tank needs to be cycled all over
again.
Tip - When you have moved on to your
second tank, you can short circuit the delay by adding some of your old substrate or filter material to your
new tank. This will already contain the bacteria and will 'seed' the tank to speed up the
process.
Read about the Household ammonia cycle next
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