Ammonia not dropping and no Nitrites

Ammonia not dropping and no Nitrites

One of the most important things to monitor in an aquarium is the nitrogen cycle, which helps keep the water clean and healthy for fish and other aquatic life. The nitrogen cycle is a process that involves the conversion of ammonia to nitrite and then nitrite to nitrite by beneficial bacteria in the aquarium. However, in some cases, ammonia levels may not decrease and the water may not contain detectable nitrates, which may indicate a problem with the nitrogen cycle. In this blog post, we’ll discuss why this might happen and what you can do about it.

Possible Causes of Ammonia Not Dropping and No Nitrites

  • New Aquarium: If the aquarium is new, the nitrogen cycle may not be fully established yet. It may take a few weeks for the beneficial bacteria to colonize the aquarium and start processing the ammonia.
  • Insufficient Beneficial Bacteria: Another cause of high ammonia and no nitrates is an insufficient number of beneficial bacteria. This could be because the filter was over-cleaned, the filter media was changed, or the aquarium was treated with chemicals that killed the beneficial bacteria.
  • Overfeeding: Overfeeding can lead to an excess of uneaten food in the aquarium, which can increase ammonia levels.
  • PH problems: If the pH of the water is too high or too low, it can affect the ability of beneficial bacteria to colonize the aquarium and convert ammonia to nitrates.

What to Do When Ammonia is Not Dropping and There Are No Nitrites

  • Monitor water parameters: Regularly monitor ammonia, nitrite and nitrite levels in the aquarium. Record readings and observe any trends.
  • Do frequent water changes: Frequent water changes can help reduce ammonia and other pollutant levels in the aquarium.
  • Add Beneficial Bacteria: Add a bacterial supplement to the aquarium to increase the number of beneficial bacteria. Make sure the supplement contains Nitrosomonas and Nitrobacter bacteria, which are responsible for converting ammonia to nitrite and nitrite to nitrite, respectively.
  • Reduce feeding: Reduce the amount of food given to the fish to avoid overfeeding, which can lead to an excess of uneaten food in the aquarium and lead to high ammonia levels.
  • Adjust the pH level: If the pH is too high or too low, adjust it to a suitable range for beneficial bacteria to thrive.

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Why is my ammonia not dropping in tank?

High levels of ammonia in an aquarium can be dangerous to fish and other aquatic life. If you find that your ammonia levels aren’t going down despite regular water changes, there could be a few reasons.


One of the most common causes of high ammonia levels in a tank. Fish food releases ammonia as it decomposes. If you feed your fish too much or too often, the excess food will release more ammonia from bacterial action, causing ammonia to build up in the tank.

Deficiency of Beneficial Bacteria:

Beneficial bacteria are responsible for breaking down ammonia and converting it into nitrites and finally nitrites. Without these bacteria, ammonia levels would remain high. If you’ve recently started a new aquarium or cleaned your filter with chlorinated water, this can kill beneficial bacteria.

Dead fish or plants:

Dead fish or plants can cause a sudden rise in ammonia levels. Be sure to remove any dead or decaying organic matter from your tank as soon as possible to prevent this from happening.

Why do I have ammonia but no nitrites?

If your tank has high ammonia levels but not nitrates, it is likely because the nitrogen cycle has not yet been fully established. In a new aquarium or after a major water change, the beneficial bacteria responsible for converting ammonia to nitrates may not have had a chance to colonize yet. This process may take several weeks to complete.

Another possibility is that your nitrate level is too low to register on your test kit. Make sure your test kit is working properly and that you are following the instructions correctly.

How long does it take for ammonia to break down into nitrite?

The breakdown of ammonia into nitrate is the first step in the nitrogen cycle, which is essential for keeping fish and other aquatic life healthy. Ammonia is converted to nitrate by beneficial bacteria, which need time to colonize a new aquarium or filter.

Under optimal conditions, it can take anywhere from two to six weeks for the nitrogen cycle to become fully established in a new aquarium. During this time, ammonia levels will gradually decrease as bacteria convert it to nitrate. Nitrate levels will then rise, and eventually, nitrite will convert to nitrite.

Why is my ammonia still high after water change?

If your ammonia level is still high after a water change, it may be because the water changes were not frequent enough or your filter is not working properly. It’s important to test your water regularly and make sure your filter is working properly.

If ammonia levels remain high, you can try adding more beneficial bacteria to your tank. You can do this by using a bacterial supplement or adding filter media containing live bacteria. Be patient, as it may take several weeks for bacteria to fully establish and ammonia levels to drop.


A high level of ammonia and no nitrates in an aquarium may not be a cause for concern as it indicates a problem with the nitrogen cycle. It is important to find the cause of the problem and take necessary steps to correct it. Regular water testing, partial water changes, and the addition of beneficial bacteria can help re-establish the nitrogen cycle and create a healthy environment for aquatic life.