I recently bought a fish tank. I googled about basics for setting up a fish tank. Almost every webpages help me to understand how important the nitrogen cycle is for a healthy fish tank. So I decided to learn about how to do nitrogen cycle and googled allot from the past few days. But by reading many articles, I am really getting confused about the entire cycle process and also many of the beginners like me don't know the correct process. Anyway I decided to start cycling from this weekend with the knowledge I got from different sources. But I just need to ask you guys that the procedure am going to do is correct?. Please advice me or correct me if I am going to do this in wrong way. I just explained the cycling process am going to do in a overall view below.

Day 1: I am setting up my tank with air pump, filter, heater, gravel, substrate, plants and a pH level tester. I have API ammonia, nitrite, nitrate and pH test kit and water conditioner. I will add 8 small guppies. I will feed them a little everyday which they can eat in 2 or 3 minutes.

Day 4: I will do 20℅water change (won't clean gravel or plants, just do top water change) without testing the ammonia level.

Day 8: I will test the ammonia level first before changing water. If ammonia is below 1ppm, I will leave the water as it is without changing. If ammonia is above 1ppm, I will do a water change by 40℅ and clean 1/4 th of the gravel or substrate and gentle clean filter.

Day 12: I will do 20℅water change without testing the ammonia level.

Day 16: I will test ammonia and nitrite levels before water change. If ammonia and nitrite levels are below 1ppm, I will leave the water as it is without changing. If the ammonia and nitrite levels are above 1ppm, I will do a 40℅ water change and will clean 1/4 th of gravel or substrate and gentle filter clean.

Day 20: I will do 20℅water change without testing the ammonia and nitrite level.

Day 24: I will test ammonia, nitrite and nitrate levels before water change. If ammonia and nitrite is below 1ppm and nitrate is below 10ppm, I won't make any water change. But if ammonia or nitrite is above 1ppm, I will do a 40℅ water change and clean 1/4 th of gravel and substrate and plants and gentle filter clean.

And I will continue the below process in every four days till ammonia and nitrite levels reach 0ppm.

Continuation Process: I will test the ammonia, nitrite and nitrate levels before water change. If ammonia and nitrite is below 1ppm, I will leave the water without changing. If it's above 1ppm, will do 40℅ water change and clean some portion of gravel, substrate and plants.

I am not much aware about the nitrate test. What should I do if the nitrate level goes above 10 or 20 ppm?. Should I need to change water?. Is high level nitrates harmful for fish?

And also not aware much about the pH tester. Do I need to test pH level also along with the ammonia, nitrite and nitrate test and add pH controller agent based on the pH result?

Any advice will be helpful for people like me who are beginners in this hobby :)

  • 2
    If you read a lot and plan to put the fish in the tank at day one, you didn't read enough, yet. Apr 28, 2017 at 13:30
  • 2
    Now I understood about the fishless cycle. Some of my friends suggested to do fish in cycle. Now I know it's better to do with fish food or pure ammonia instead of harming fish's life.. Thanks again
    – Arun
    Apr 28, 2017 at 13:45

2 Answers 2


The most important thing first: Don't put any creature in the tank at the beginning/before the tank is fully cycled!

Providing a time line is nonsense because the cycling can take between 1 and 4 weeks. The phases are sufficiently defined by the ammonia, nitrite and nitrate levels - you understood them correctly as mentioned in your question - no need to repeat them here. Note that there can be second peak of nitrite which can still be harmful for the inhabitants.

The nitrate level mostly influences the health of your plants. If the filter is working well (no ammonia and no nitrite), then the nitrate level is influenced by the amount of food and the number of creatures in the tank. You'll figure out a water change interval to lower the nitrate level through regular tests. Change 20 % at least every two weeks - collect the cold water from your shower to save monetary and environmental costs.

The test work independently. The PH value should be adjusted to match your fish or better your fish should match the PH value of the tab water. Usually you get them from a local store where the experts tell you whether the fish are kept in tab water or treated water. Changing water values is not a beginners task and goes beyond the scope of the question.

Chlorine should not be measurable in the water added to the tank with the usual test strips/kits as it destroys essential bacteria in the filter, water and gravel which destabilizes the water values (and higher concentrations can of course harm the inhabitants directly). Chlorine can be removed chemically with water conditioners (the use is controversial and out of scope for this question and answer) or by leaving the water for a few hours so that the chlorine evaporates.


To cycle a fish tank, you fill the tank with water and gravel and add water conditioner. Then start the pump and heater, let the water heat up. This takes a day or two.

After 3-4 days, the water gets cloudy (normaly light grey). Then put a small amount of fish food in your tank (no fish in the tank, plants are OK). You then wait for a week and test the water, there is most likely ammonia in the water by now and maybe nitrite. Wait one more week and test the water - the level of ammonia has hopefully fallen by now. If it has, put some fish food in the water and wait one more week and then test the water again. There should be no ammonia detectable by now, but the nitrite level will be high. We are now at the end of the 3rd week. You wait one more week, then test the water - there is now hopefully no detectable ammonia and nitrite level is low or on its way down. There is most likely some nitrate in the water by now - this is what we want. We are now at the end of the 4th week. If the water is OK by now, change half of it and put a couple of fish in your tank. If the water still contains ammonia or nitrite, you will need to wait until the levels are safe for the fish.

There is a possibility to buy bacteria mix to shorten the time it takes to cycle a tank, but this is not very effective. You might also get matured filter media from a friend and put this in your filter, but this method might introduce diseases to your fish tank, so be careful.

There are some good water test strips to buy with all the necessary tests in one strip. Ammonia and nitrite must be as low as possible, pH is best if close to 7,0. The general hardness (GH) around 7 to 14, the carbonate hardness (KH) around 6-10. Chlorine has to be zero. Different fish and animals need different water values.

More information about cycling the tank could be found in the relevant article on fishlore.com.


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.