How to "Cycle" Your Tank

What is the Nitrogen Cycle?

Ammonia is toxic!

Ammonia is produced by:

Your axolotl’s waste (💩)
Decaying organic matter (food, plants, anything that is dying)

Beneficial bacteria can get rid of this toxic ammonia!

There are two types of beneficial bacteria:

The first type converts ammonia into nitrites. But nitrites are also toxic!
The second type converts nitrites into nitrates. Nitrates are only toxic in very high concentrations. Excess nitrates are:
- Removed by doing water changes (replacing some of the dirty tank water with fresh water).
- Consumed by live plants for nutrients.

This whole process is referred to as the Nitrogen Cycle.

Axolotl creates waste→Waste creates ammonia→

Bacteria converts ammonia into nitrites→

Bacteria converts nitrites into nitrates→

Nitrates are removed with water changes.

What is "Cycling"

"Cycling" is the process of growing this beneficial bacteria in your tank's filter prior to adding the axolotl to the tank. This way, when the axolotl is added to the tank and their waste starts producing ammonia, the beneficial bacteria will consume ammonia and nitrite keeping the levels constantly at 0ppm (parts per million). Keeping ammonia and nitrite levels at 0ppm is vital to keeping your axolotl healthy!

There are two ways to cycle:

"Fish-in" - Fish are placed in the tank to produce ammonia but have to endure the toxicity while cycling

"Fishless" - Pure liquid ammonia is manually added to the tank.

We will only cover "fishless" cycling as "fish-in" is considered unethical.

Cycling Instructions

What you will need:

Water Conditioner: Seachem Prime
Ammonia: Dr. Tim’s Ammonium Chloride Solution (or plain household ammonia with no fragrance or anything added)
Testing Kit: API Freshwater Master Test Kit

Note: Before you start cycling, it is good to know your tap water’s normal parameters. Use your API test kit to test your tap water’s pH, ammonia, nitrites, and nitrates. If your readings are outside of the following range, you may need to look into an alternative water source or a RODI system for your tap.

pH: 7ppm - 8.5ppm
Ammonia: less than 1ppm
Nitrites: less than 1ppm
Nitrates: less than 20ppm

Set up your tank and filter and add any decorations, sand, etc. you may want.
Dose tank with Seachem Prime according to directions on the bottle. This removes chlorine from your tap water.
- Always dose Seachem Prime when adding fresh tap water to the tank.
- Always add enough for the full size of the tank.
Make sure your filter is up and running.
Dose tank with Dr. Tim’s to bring your ammonia up to 3ppm.
- To confirm you’ve dosed the correct amount, wait 1 hour after dosing, then test for ammonia using your API test kit.
Wait 24 hours and then test your ammonia, nitrites, and nitrates using your API test kit.
Continue testing every 24 hours. Whenever your ammonia is less than 1ppm, dose enough Dr. Tim’s to bring it back up to 3ppm.
As you continue to test every 24 hours (and dose ammonia as needed), you will see the following happen:
- First you will see your ammonia levels go down. (It may take up to 2 weeks to see that initial drop.)
- As your ammonia goes down, your nitrites will begin to go up.
- Eventually (be patient!) you will see your nitrites begin to go down.
- As your nitrites go down, your nitrates will begin to go up.
You are cycled when you can dose ammonia to 3ppm and 24 hours later your ammonia and nitrite tests are both at 0ppm.
- Dose ammonia and test for 3 more days to confirm you are cycled.
- Until the day you are ready to add the axolotl, continue to dose ammonia but only up to 1ppm.
Do a large water change (or several) to bring nitrates below *at least* 40ppm, ideally below 20ppm (the lower, the better).
- Pro Tip: Before water change, take out the filter sponge/foam and swish it in a bucket of tank water. Give it a few gentle squeezes. This seems to help lower nitrates faster by getting the nitrate-saturated water out of the filter.
Congratulations! You may now add your axolotl!

The following can cause cycling to stall:

Problem: Ammonia higher than 4ppm
- Solution: 50% water change until ammonia is below 4ppm.
Problem: Nitrite above 5ppm (your nitrite test will look darker than the purples on the API chart)
- Solution: 50% water change until nitrite is below 5ppm. Suggest reducing ammonia dosing to 2ppm until nitrite starts lowering.
Problem: pH at 6ppm
- Solution: If your tap water has a pH above 7.4ppm, do a 50% water change to raise pH.
- Alternative Solution: Add 1 teaspoon baking soda per every 10 gallons of water in tank. (Example: 20 gal = 2 tsp, 40 gal = 4 tsp)