How to Cycle a Tank With Old Filter Media – 2 Easy Ways

Last Updated on October 20, 2022 by

Do you know how to cycle a tank with old filter media?  Do you know the purpose and function of cycling a fish tank?  If you don’t know, then you came to the right place! 

Cycling a tank is crucial to establish proper water chemistry.  Every new tank owner has to cycle their tank to get started.  To understand the purpose of cycling, you need to learn about the nitrogen cycle.

One of the best things to always remember is that you need to always keep your fish tank clean.  There are two main ways to do this.  The first way is by filtering your fish tank. 

The second way is to perform frequent water changes.  Don’t get overwhelmed by these tasks.  We have written this article to teach you all you need to know about tank cycling and care.  

We will also go over how to cycle a tank with old filter media.  This skill is very useful in saving money and not having to use chemicals to cycle your tank.  

Cycling a tank takes time.  In many cases, you need at least a month to cycle a tank to a safe place to add fish.  If you learn how to cycle a tank with old filter media, you can do this cycle a lot faster.

Keep reading now to know what to do!   You will leave this article feeling confident to cycle your fish tank!

Cycling a Tank With Water From Another Fish Tank

There are many different ways to cycle a fish tank.  We will go over a few different possibilities including how to cycle a tank with old filter media.  Before we get into those details, let’s take a closer look at what cycling is and why it is important.

Cycling a fish tank is when you help your tank’s water go through the nitrogen cycle.  This process is done to clean the fish tank of dangerous nitrites and ammonium.  You can do this in a variety of ways.

It is possible to cycle your tank with the fish still inside. Other people prefer to do this without the fish in the tank.  

Cycling A Tank With Water From Another Fish Tank

Learn more about: The Best Way How To Cycle A Tank In 24 Hours

When you cycle your tank, you are working to keep the water chemistry balanced.  When nitrite and ammonia exceed a certain level, your fish can die.  This is because they are not able to do crucial things for their survival. 

1. The most common practice is to cycle your tank before adding the fish.

  Cycling helps establish the proper bacteria in your tank.  This bacteria ends up consuming nitrites and ammonia and converting them to harmless nitrates.  To get started with your cycle process, your whole tank needs to be set up.  This includes all the hardware like filters, pumps, pipes, and a water heater if necessary. 

Once everything is set up, you can add water to start pumping it through your filter.  If you have a healthy fish tank with good bacteria, you can use some of the water from that tank to put into your new tank.  

2. Another option is learning how to cycle a tank with old filter media.

Fish Tank Filter

How Much Time Does It Take To Cycle a Tank With Old Filter Media?

As mentioned earlier, really establishing the proper bacteria, takes time.  On average it will take between 4-6 weeks for your tank to be ready.  One way to speed this process up a bit is to use filter media from another healthy fish tank.  

Please make sure that this old filter media is coming from a good fish tank.  If you take it from an unhealthy fish tank, you are simply spreading that imbalance into your new tank.

Install the old filter media into your new filter.  From here, you can start the cycling process.  Turn on your pump and allow for your new tank water to pass through the old filter media.

This has to keep going until you can measure that the ammonia levels are at 0.  The best way to do this is to use a nitrate and ammonia test kit.  They are easily available for purchase at most pet stores. 

According to New Mexico State University, “As a general rule, start-up systems should be tested daily so that adjustments can be made quickly when needed.”  If you want to speed up the cycling process you can try to use a tank heater. Bacteria will grow faster in warmer temperatures.  

Overall, cycling a tank is an important step that should not be skipped.  Now you know how to cycle a tank with old filter media.  Simply take a cut out of it and add it to your new tank’s filter.  

Hopefully, you feel ready now to get started.  Good luck!

Feel free to comment and ask questions below.

Read more about: The Top Tips On How To Cycle A Fish Tank With Goldfish


Do you need to cycle a tank if you have a filter?

Yes, you need to still cycle a tank even with a filter. A new filter does not have any beneficial bacteria established. This means it will not be useful in consuming nitrites. As you cycle your tank, the bacteria will begin to colonize your filter. Be aware that this process takes time. On average it can take between 4-6 weeks to successfully establish enough bacteria to keep your ecosystem balanced.

How long does it take to cycle a tank with old filter media?

If you cycle a tank with old filter media, it might speed up the process a little bit. However, the best way to measure the rate of your cycling is to keep testing ammonia levels every day. When the test consistently shows up as 0, you know that you are good to put fish in your tank. When you use an old filter media it will still take at least 4 weeks.

Can you cycle a tank with old filter?

It is possible to cycle a tank with an old filter. However, you need to be careful of the source of that filter. Make sure that it came from a healthy fish tank that was very balanced. These old bacterias will kickstart your new tank!

Can you cycle a tank with water from another tank?

Yes, you can cycle a fish tank with water from another tank. But you should only use about 25% of that water and mix it with new water.

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