Tank Cycling 101

One important and often overlooked aspect of setting up an aquarium is tank cycling. This is the process of getting the good bacteria to grow in your aquarium. The Nitrogen Cycle begins when ammonia starts to build up in the tank and bacterias that convert ammonia into nitrite starts to develop. Once the nitrite starts to build up, bacteria that converts nitrite into nitrate starts to grow. Nitrate is reduced through regular water changes and plants utilizing the nitrate for food.

Now, you’re probably wondering how to start cycling your tank. Ammonia doesn’t just appear out of nowhere, it is either added directly by you, or fish in your tank. There are two ways to begin cycling an aquarium:


1) The Fishless Cycle – This is the most humane way of cycling an aquarium.


Once your tank is aquascape and filled with water, you start adding ammonia. You need to make sure you add pure ammonia (the only ingredient should be ammonia), and there should be no fragrances.


Add ammonia to the water and test the ammonia levels in your tank until you are at about 2-3 ppm. This may take some trial and error, and the exact amount to add will depend on your tank size. Adding ammonia artificially will encourage beneficial bacteria to grow. Check the water parameters regularly, and you’ll notice the ammonia will eventually start to decrease and the nitrite increase. At this point, you need to continue to add the ammonia to maintain a steady 2-3 ppm. After a while, the nitrite will begin to decrease (remember to be patient with this step! It may take a while before you start to notice any difference in your water parameters). Once the nitrites have reached 0 ppm, your tank’s Nitrogen Cycle is fully established.


At this point, you can add less ammonia (about 1/2 as much) until you are ready to add fish. Before adding fish, however, it’s important to do a 70%-90% water change to get the ammonia and nitrate levels down to make your tank safe for its new residents.
Total time for the fishless cycle: 3-5 weeks.


2) The Fish Cycle – This cycle involves putting hardy fish into an uncycled aquarium. This is what I did for my first aquarium, and it is what most people will do because most people want to have instant gratification than having an empty aquarium (safely and humanely cycling) for weeks. This process yields the same results as the fishless cycle, except there is a high chance some fish may die from the ammonia and nitrite spikes. Just because they are fish doesn’t mean they are worthless.
Total time for the fish cycle: 3-5 weeks.


I recommend the first method. I was naive when I made my first aquarium and did a fish cycle (no casualties, fortunately). I have since then learned of the better plan for tank cycling. It is important to note that both cycles need to have a filtration system and the fish cycle requires weekly water changes to prevent toxicity in the water from getting too high.

One thought on “Tank Cycling 101

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s