After recently talking about why your tank may have a nitrite spike after a water change, we noticed a number of people asking how long it takes for nitrites to go down in their tank in general.
Due to their being so much confusion about this within the pet keeping community, we wanted to publish this dedicated article on the topic to try and help as many of our readers as possible.
Our hope is that we will be able to help as many of you realize that there is no one set timeframe for nitrites to go down in your tank and that there are a number of variables involved.
As with many things in the fish keeping hobby, patients really is a virtue and time will be a key factor in letting your nitrites go down naturally when needed.
How Long For Nitrites To Go Down Naturally?
The simple answer to this question is that there is no one set time for nitrites to go down in your tank.
This is because the rate at which nitrites are broken down and used by bacteria in your aquarium filter will vary depending on a number of different factors.
These include the amount of surface area available for bacteria to colonize in your filter, the amount of organic matter in your tank for bacteria to feed off and the current water temperature.
In terms of a more specific answer, we would generally expect nitrites to start falling after around 1-4 weeks of a brand new tank being set up.
However, it is not uncommon for it to take 6 weeks or more for nitrites to completely disappear from a tank that is cycling, especially if you are a beginner.
One key thing to remember is that the level of nitrites in your tank will fluctuate during the cycling process and it is not uncommon for them to spike back up again after appearing to fall.
This is generally nothing to worry about and as long as you are seeing a overall trend of nitrites falling over time, your tank is likely to be on track.
A sudden and large spike in nitrites (known as a nitrite spike) can often be caused by a number of different things such as overfeeding, excessive organic waste or a sudden drop in pH.
If you see a large nitrite spike in your tank, it is important to take a look at what may have caused it and make any necessary changes.
Once you have done this, nitrites should start falling back down to more acceptable levels within a few days.
How To Make Nitrites Go Down Faster!
If you are impatient like many of us are when it comes to our tanks, there are a number of things that you can do to try and speed up the process of nitrites falling.
One method is to increase the amount of surface area in your filter for bacteria to colonise.
This can be done by adding more media such as ceramic noodles or extra sponges.
You can also add a bacteria supplement to your tank which will help to increase the number of nitrifying bacteria in your aquarium.
Bacteria supplements come in both liquid and powder form and are available from most good pet stores.
Another method of decreasing nitrites is to raise the water temperature in your tank.
This is because nitrifying bacteria generally reproduce more quickly at higher temperatures.
However, it is important not to raise the temperature too much as this can cause stress to your fish.
A good rule of thumb is to raise the temperature by 2-3 degrees Celsius above the current temperature.
How Long Does It Take For Nitrites To Go Down In A Reef Tank?
Reef tanks are a little different to standard fish only tanks as they generally have much higher levels of nitrates.
This is due to the fact that reef tanks often contain a lot of live rock which provides a large surface area for bacteria to colonise.
The level of nitrates in your reef tank will also be affected by the number of fish and invertebrates that you have as well as how much you feed them.
In terms of how long it takes for nitrites to go down, we would generally expect them to start falling after around 1-4 weeks.
However, it is not uncommon for it to take 6 weeks or more for nitrites to completely disappear from a reef tank.
As with fish only tanks, the level of nitrites in your reef tank will fluctuate during the cycling process and it is not uncommon for them to spike back up again after appearing to fall.
Why Won’t My Nitrite Levels Go Down?
There are a number of reasons why your nitrite levels may not be falling as quickly as you would like.
One reason is that you may not have enough surface area in your filter for bacteria to colonise.
You can solve this problem by adding more media such as ceramic noodles or extra sponges.
You can also add a bacteria supplement to your tank which will help to increase the number of nitrifying bacteria in your aquarium.
Another reason why your nitrite levels may not be falling is that you are overfeeding your fish.
When fish are overfed, they produce more waste which can lead to an increase in nitrites.
To solve this problem, simply reduce the amount of food that you are giving your fish.
A third reason why your nitrite levels may not be falling is that you have a sudden drop in pH.
This can often happen when you do a water change or add new live rock to your tank.
If you see a sudden drop in pH, it is important to take a look at what may have caused it and make any necessary changes.
Once you have done this, nitrites should start falling back down to more acceptable levels within a few days.
In summary, the main reasons why your nitrite levels may not be falling are:
- You don’t have enough surface area in your filter for bacteria to colonise
- You are overfeeding your fish
- You have a sudden drop in pH
Conclusion
So there you have it, a guide to how long it takes for nitrites to go down in your tank!
We hope that you have found this article helpful and that it has cleared up some of the confusion surrounding this topic.
As always, if you have any further questions or concerns, please do not hesitate to get in touch with us!
