Tank Care & Water Quality

Tank Cycling

Probably one of the most important articles on this website and I’m going to try to give you a full understanding of the cycling process and not overwhelm you.

What is “cycling”?

Cycling a tank is the NATURAL process of building good bacteria to break down waste in your tank. When a tank is considered “cycled” it means you have the appropriate levels of good bacteria to handle the amount of waste in the tank.

Many people get overwhelmed when it comes to cycling a tank. DON’T OVER THINK IT! Your tank naturally wants to go through this process. The bacteria want to be there. When you look at your axolotl/fish/any other aquatic animal setup you need to realize it is it’s own environment. You have a little ecosystem in your house that wants to thrive. When you start doing too much to it, when you start adding a bunch of chemicals, that’s where people tend to run into problems.

What is a “nitrogen cycle” or beneficial bacteria?

When waste, aka ammonia, is introduced into a system good bacteria forms that breaks down the ammonia. Ammonia is turned into Nitrites when broken down and a second kind of bacteria grows to break down Nitrites. The second set of bacteria eats the Nitrites and that is then turned into Nitrates. Nitrates are only toxic in very high levels and can be lowered by doing normal water changes (usually 25% of your tank’s volume) or can be absorbed by live plants.

tank cycle

How does ammonia end up in my tank?

Ammonia comes from waste/poop, dying plant matter, uneaten food left in the tank or any organic matter that begins to break down.

How do I cycle my tank?

There are two methods that you can use to cycle a tank:

1. Cycling with livestock: using cheap fish to add ammonia

2. Fish-less cycle: adding pure ammonia directly to a tank (no livestock)

The fish-less cycle is the best way to go so you don’t accidentally harm something while getting your tank cycled. Remember ammonia is toxic and could end up killing the fish you are using to cycle the tank.


Steps for a fish-less cycle:

  1. Have your tank setup up and running with de-chlorinated water (I highly recommend using Prime for Axolotls).
  2. Make sure you have plenty of living space for your good bacteria to grow (bio-media in your filter, adding a sponge filter along with your mechanical filter, live plants, etc). Adding lots of good areas for your bacteria to call home helps in a number of ways: (faster cycle, a more stable tank – so less crashes if something happens and less issues with blooms/milky tank).
  3. (optional) Use a heater to bring the temp up to 76-ish degrees (NO AXOLOTLS IN THE TANK). Having warmer temps to work on cycling your tank helps the bacteria reproduce faster so you have a shorter wait period. Of course you’ll have to cool the tank back down before you put your axolotls in.
  4. You’ll need a test kit to watch your water parameters.
  5. Add pure ammonia to your tank (some fish stores might carry it or you can order it online). You want the ammonia at 4ppm (over 5ppm and the ammonia will be too toxic for the good bacteria).
  6. Fish-less cycling usually takes about 3-4 weeks. You’ll want to feed the tank with the pure ammonia and test for ammonia, nitrites and nitrates.
  7. Once you start seeing your nitrites go up it means you have started growing the first set of bacteria.
  8. Then when nitrates have started showing up on your tests it means the second set of bacteria are now in the tank.
  9. You’re done cycling when your ammonia and nitrites are at 0. You will have a small amount of nitrates and that is great! Your tank is now cycled and safe to add living creatures, you can stop adding ammonia.
  10. During your fish-less cycle do NOT do any water changes even if the tank gets cloudy. That milky/foggy color is a good bacteria bloom. When you do a water change while this is happening you are removing a bunch of the good bacteria that are trying to reproduce to get to appropriate levels. You are essentially restarting your cycle.

Notes: Your pH will probably fluctuate during the cycling process. It’s normal and you don’t need to mess with it! It will even out again once the ammonia goes down. As long as you didn’t use distilled water (please don’t ever do that) you have minerals and natural buffers that control the pH (if you do have pH issues with your tap water we will discuss that in another post).

Parameters on a cycled tank

Please please please….remember, your tank wants to self maintain. Many people want to try a do a quick fix with different chemicals and it almost always ends up in disaster at some point. Once you have an established/cycled tank care will be very easy.




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