Filter overflowing in an aquarium is a common issue that disturbs the whole habitat and environment within the fish tank.

Why is My Aquarium Filter Overflowing? Generally, clogging and excess residues are the main reasons for aquarium filter overflowing. In addition, the installation of wrong-sized filters, over-filled tanks, and high speed of filters are also the cause of overflowing. 

The filter is one of the essential pieces of equipment in the fish tank that helps to keep the atmosphere and inhabitants lively and active.

Ensuring good filtration in your fish tank is a big responsibility to avoid toxicity in the tank and keep animals happy and thriving.

Problems with the filter often occur, and correcting these immediately, is necessary as it is critical to the fish’s health.

However, despite having good knowledge and research as an aquarist, you can still encounter issues with these types of equipment.

Why is My Aquarium Filter Overflowing?

Filter overflowing does not mean that it starts to pass or flow tank water at high speed or maximum volume.

It is a problem in which the water starts flowing over the top of the filter and through the gap where the intake tube is present.

Also, the water may start coming over the back and look like there is a flood around the filter.

Excessive accumulation of dirt and residues in the filter media

Accumulation of dirt, residues, leftover, and debris of plants and animals in the filter media becomes the barrier in the passage of water.

This blockage or restriction in the water flow on the media disturbs the normal water cycle so, the overflowing starts.

The water does not purify completely, and the loaded media begins to pollute the environment.

You should know that this is the time to change media as soon as possible to avoid further complications.

You can also rinse the media with tank water in a separate bucket and insert it back: you will observe some improvement.

I recommend changing the filter media after every four weeks at least: you can also change it early if you observe excessive dirt.

Clogged filter pad or intake

Clogging occurs when you do not clean or wash the filter for a long time, and the junk starts to build up.

Filter pad and sponge on intake with time start to disturb water flow by acting as a blockage in the intake tube.

You can remove this clogging by rinsing the filter thoroughly: try to clean and scrub every part to remove all impurities.

Also, clean the filter pad and sponge separately by squeezing them with your hands: do not wash them with untreated water.

Top fin and whisper filter

There are many brands and types available in the market that offer you the best filters for your aquarium. 

Top fin and whisper are common types of filters for fish tanks that you can use in your small to big aquariums.

Despite being popular, they overflow water, which is their biggest drawback: they also slowed down with time.

Also, the thing sponge between the cartridge and path of water exit, plug up in whisper filter.

If the issue is in the sponge, remove and rinse it well or change it, while doing this also does not help in these filters.

I prefer to use a good filter with the best filtration power and is easy to maintain, such as Aquaclear. 

Incorrect positioning of the aquarium filter

When you install the filter at the wrong location and in the wrong position, overflow may occur.

Usually, it should lie just above the water level or in the water, depending upon the type.

Sometimes, due to incorrect positioning or slightly angular installation, the cartridge does not stay in its place.

You need to slightly tilt the filter towards the tank so the water will more efficiently flow through it without overflowing.

Lack of filter floss

Filter floss is necessary to catch all the debris and impurities that pass through the intake.

This padding helps to keep the flow optimal and provides you with extra filtration.

In its absence, the filter is more likely to block and clog soon, particularly in small aquariums and when you overfeed your fish.

You should add this padding in the intake tube, which will improve filtration and also act as the site of bacteria cling.

I do this in my tank, and it makes it much easier for me to clean the tank and filter are per requirement. 

It is essential for the aquariums with more fish and plants in the tank that produce more wastes as they have a heavy bioload.

Carbon in the fish tank filter cause overflowing

Filter carbon is the media that removes impurities from the water when it flows through the filter.

Also, it is a necessary component when you have a smelly tank or trying to remove tabs from the tank.

This activated carbon improves the water quality, but you can avoid it as it may become a reason for overflowing.

Removing the carbon from the fabric pouch will help eliminate the issue. 

The water will move afterward without disturbance. In this case, you have to be more careful about the cleaning of the tank.

High speed or flow

Any disturbance in the speed or flow of water through the filter leads it to move abruptly.

High speed is necessary for some tanks to resemble the natural habitat of fish, but it may cause other problems.

Moreover, the water starts passing through without proper filtration and purifying.

A large portion of water starts missing the filter, and you will get no benefit in installing it.

However, it is necessary to match the natural environment of inhabitants in the tank but try to keep the flow rate medium to avoid abruption.

Wrong filter corresponding to the aquarium size

Aquarium size, water volume, and equipment should correspond to each other for a healthy tank environment.

If you have a small tank of 10-gallon size and fill water above the required level, the small size filter will automatically start overflowing.

You should recognize your tank size and suitable filter for it and avoid overfilling it.

Sometimes you need two filters for a single aquarium when you have planted more plants in it and require more oxygenation levels.

What happens when the aquarium filter is overflowing?

Filtration is essential in an aquarium, and the absence of sufficient filtration, the following problems arises:

• Toxicity starts to increase in the tank
• Oxygenation level decreases, and carbon dioxide level increases
• The pH starts to lower in the aquarium, which is harmful to the fish.
• Ammonia, nitrates, and other wastes start to accumulate in the tank.
• Animal and plant life becomes threatened and makes them scared.
• A high or low flow rate prevents the fish swim freely.

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