How Often Should You Change an Aquarium Filter?

-- By Carol

Aquariums are aesthetically pleasing and also provide an artistic effect to the room.

The plants, the colorful fishes, and the décor have certain therapeutic benefits like reducing stress and lowering blood pressure and are known to make one calm.

However, all these benefits as well as the overall beauty of an aquarium can’t truly be enjoyed if it isn’t properly maintained.

An aquarium filter plays a major role in maintaining the health of your aquarium. It keeps the water clean, increases ventilation, and enhances the wellbeing of the inhabitants.

The filter has to be cleaned and changed in a timely manner. The pressing question here is how often should the aquarium filter be replaced?

If you’re interested in answers to that question and more, read on to find out everything you need to know about changing an aquarium filter.

Table of Contents

How Often Should I Change an Aquarium Filter?

The filter helps in ensuring the overall efficiency of the aquarium.

Without the right filtration process, the water inside can turn toxic to the fish.

Therefore, maintaining a regular cleaning routine and servicing the system is an integral part of aquarium maintenance.

While all aquarists understand the importance of the filtration process, they are not too sure about the frequency at which the filter should be changed.

Changing or replacing the aquarium filter mostly depends on the kind of filter you are using in the aquarium. Some filters might need more frequent changing than others.

For instance, mechanical filters don’t need to be changed until they start falling apart because replacing them earlier than that can actually harm the inhabitants. Chemical filters can be replaced monthly, while biological filters also don’t require frequent changing.

Replacing the filter too many times can result in damage as it can cause the removal of important bacteria.

Therefore, in order to balance out the filter change, it is best to invest in good quality gravel or sand which comes with pre-added bacteria.

Generally, you should change the filter when you notice the media of the filter falling apart.

Types of Aquarium Filters

There are three types of aquarium filters that you can use:

Mechanical filters
Chemical filters
Biological filters

Let’s have a look at these three main types of aquarium filters.

Mechanical Filters

This type of filter forces the water to go through media like a sponge, to eliminate any solid debris and other foreign materials.

Mechanical filters keep the fish tank clear of unnecessary and harmful materials and maintain clear water.

There isn’t a need to replace this filter until the media is falling apart or the filter itself stops working.

Replacing or changing mechanical filters or even its media unnecessarily can actually result in negative outcomes.

With time, the media of this filter gets covered with beneficial bacteria that start acting as a biological filter for the aquarium.

When you remove the media or the filter, it also means that you are removing the beneficial bacteria.

Eventually, however, the filter media will start clogging up. All you need to do is rinse the media every month to unclog it or to prevent clogging.

This is also an ideal time to change the water of the aquarium.

This way, you can use the aquarium water to rinse the media before changing it.

This also helps in keeping most of the beneficial bacteria in the filter media. You can also rinse using conditioned water but avoid using unconditioned tap water.

You must change the media of the filter in case it is falling apart or if the filter isn’t working properly.

Be sure to leave the old filter media in the water for a few weeks after you install the new filter long enough for bacteria to accumulate on the new media.

Chemical Filters

This filter focuses on removing all the impurities from the aquarium water. The commonly used media for this filter is carbon.

In a chemical filter, the media works by absorbing all the particles which fill up eventually and saturates.

It is ideal to change the chemical filter every month, or after two months at the least.

Biological Filters

Biological filtration allows beneficial bacteria to break down the ammonia in nitrites.

The nitrates are broken down further to reduce their toxicity. The bacteria grow all over the aquarium, particularly in the gravel.

Just like the mechanical filter, there isn’t a need to change the biological filter, unless it stops working or falls apart.

It must also be rinsed and cleaned monthly or at least once after two months.

Aside from the changing schedule, the cleaning of the aquarium filter is also important.

While chemical filters won’t need much cleaning since they are replaced each month, you will still have to clean the mechanical and biological filters to maintain the wellbeing of your fish.

Transitioning from Old to New Filter in an Aquarium

The majority of new aquarists are quick to discard the old aquarium filters as soon as they get their hands on a new one.

In this eagerness, they immediately get the filter installed but completely neglect the one main thing – the beneficial bacteria that had covered up the old filter media.

They typically throw it away along with the filter.

As a result, they do get amazingly clear water but the health of their fishes starts getting affected. For some of the inhabitants, this can even prove fatal!

Why does this happen?

When the beneficial bacteria-filled filter gets removed from the aquarium water, the entire ammonia cycle inside crashes.

Think of the old filter as the heart of your aquarium’s ecosystem.

When you remove it, you are also removing the most crucial part of the system.

This means the ammonia cycle is disturbed for the next few days until new bacteria start forming.

Since there are no bacteria to break down the buildup, nitrite and ammonia levels escalate.

To avoid this, here are a few tips to follow to make the transition from the old filter to the new one as smooth as possible:

New mechanical filters can easily get adjusted in the aquarium, simply by leaving the old filter media in the aquarium for two to three weeks before you discard it. However, this is not the same with chemical and biological filters.
These two aquarium filters need some time to allow the process to happen. When installing the new filter, it is ideal to chop the older filter up and include it in the new one. This ensures that the new filter is able to buildup the bacteria from the older one.
When installing chemical filters, you must make sure that the setting is the same as the one recommended for the aquarium. It is significant that the number of nitrites, ammonia, and nitrates is steady throughout this transition. You can examine the chemical levels through some tests if needed.
You can also keep both the old and new filters running at once for a week or so to allow the new filter enough time to get colonized.

These tips will make sure that you easily install the new aquarium filter without affecting the health of the fishes and the overall aquarium’s environment.

Tips for Maintaining the Aquarium Filter

The filters of the aquarium don’t necessarily need cleaning as doing so will remove the beneficial bacteria.

Their main aim is to collect the toxins and eliminate them from the aquarium water. This also means that the filters can’t really stay clean.

Here are a few tips to maintain the aquarium filters properly:

Mechanical Filter – all you need to do is to ensure that the filter media is working properly. It is essential to rinse off the media once in a month to unclog it so that it continues functioning correctly.
Chemical Filters – these should typically be changed once a month or at least once every two months. When the water starts becoming cloudy, you should replace the carbon.
Biological Filters – if this filter starts malfunctioning, getting clogged, or isn’t working slowly then it is time to give it a good rinse.

If your fish are getting sick, the filters might need more cleaning or must be replaced.

There could also be some other issues with the aquarium. It is best to seek professional help if this happens.

The maintenance of the filter is highly important for ensuring the overall good health of your aquarium.

Monitoring the aquarium water and its inhabitants is a good indicator of whether or not the filter is doing its job.

A damaged or faulty filter can result in ammonia buildup in the water which is toxic to the fishes.

With consistent care, you can eliminate the chances of possible biological crashes and other issues that arise due to filtration problems.

Don’t neglect the maintenance of the filter, until problems start arising.

The biological stability of the aquarium is important and isn’t even complex, it just needs consistency and diligence.

Rinse the filter media and change the filter as per the schedule to ensure a smooth transition so that your aquarium is continuously working at its best and your fishes and live plants stay healthy.

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