Are Internal Aquarium Filters Good? (Better Than External Filters?)

Image of an aquarium with an internal filter

Filters are essential for the smooth functioning of aquariums. A good filter eliminates solid waste and dissolved toxins in an aquarium and keeps it clean. Now, internal filters are preferred by many fish tank owners because they are compact, easy to install, and less expensive than external filters. But are internal aquarium filters good for all types of tanks?

Whether internal aquarium filters are good or not depends on the aquarium setup. Internal filters are small, so their ability to hold filter media is not much. This makes them suitable for small tanks with a few fish. However, they are not good for large or crowded tanks or those with messy fish.

Let’s talk about this in more detail now.

How Does An Internal Filter Work?

There are different types of internal filters, like air-powered filters, power filters, and canister filters.

All these filters must be placed inside a fish tank, with the outlet below the water surface. The main body or compartment carries the filter media.

Depending on the make and model of the filter, it may have biological, mechanical, chemical filtration media, or a mix of these.

Water from the tank enters the filter and passes through the filter media inside it. Mechanical filter media trap the debris and dirt. Chemical and biological filter media convert toxins like ammonia into less harmful substances.

Once the filter cleans the water, it pumps it back into the tank through an outlet pipe.

Internal filters cannot perform extensive filtration. Due to their smaller size, they cannot hold much waste.

If you allow a filter to operate for a long time without cleaning it, it will not operate efficiently. Hence, you must clean it frequently.

Recommended Further Reading:

Pros And Cons Of Internal Aquarium Filters

The primary function of an aquarium filter is to keep the water clean for its inhabitants. It helps the aquatic creatures enjoy optimal living conditions as they do in their natural habitats.

In the wild, fish live in large water bodies. The continuous circulation of water and natural filtering mechanisms of these environments ensures that toxins produced by fish are continuously removed.

However, fish tanks are confined spaces. Fish eliminate waste into their surroundings, and it has no place to go. This natural waste remains in the water, degrades, and releases harmful toxins.

If you leave it untouched, the toxin levels increase over time, leading to ammonia spikes and other toxic effects that adversely affect aquatic life.

To prevent these consequences, you must make suitable arrangements to remove toxins and waste from this environment.

The main job of an aquarium filter is to clean the water. However, it may also aerate the water and adjust the water flow.

Internal aquarium filters are compact, inexpensive filters. They are built for small to medium fish tanks. These filters use mechanical and biological filtration mechanisms to trap dirt and debris and clean the water.

They continuously filter small volumes of water. Due to their small size, they also produce very little noise during operation. Many internal filters also aerate the water and improve the dissolved oxygen content.

Internal filters are not a good choice for large fish tanks that hold more than 40 gallons of water. They will also not be enough if the fish tank is overcrowded or your fish are very messy.

The more the fish and the bigger they are, the more organic waste they produce. Large amounts of waste will significantly pollute the water.

You will need an efficient filtration system to tackle this waste build-up and keep your tank clean.

Internal aquarium filters cannot clean large volumes of water. They are not designed to clear highly turbid water.

The limited amount of filtration media in these filters will quickly get exhausted. Hence, they are not a practical solution for large fish tanks.

Additionally, they cannot cope with the waste produced by large and messy fish. If you keep cichlids, goldfish, or other big fish that produce copious amounts of waste, you need a better filtration system.

It should be able to trap the physical waste and prevent the water from becoming cloudy. Additionally, it should also act on the toxins in the water before they increase to dangerously high levels and affect the fish.

In these cases, an external aquarium filter is better. Although external filters are big, bulky, and more expensive, they can handle the demands of big and messy fish tanks.

Related Further Reading:

Are External Aquarium Filters Better Than Internal Filters?

When it comes to choosing filters for your fish tank, over-filtration is not a concern. However, an undersized filter can compromise the overall cleanliness of your fish tank. Hence, bigger is better.

Internal filters will work perfectly for fish tanks with a capacity of 25 gallons or slightly higher. However, if your fish tank is big and has messy fish, it is ideal to upgrade to an external filter for more filtration efficiency and less effort.

External filters hold large amounts of filter media. They trap floating debris and dirt. They also act on dissolved toxins in the water.

An external filter will keep the water in your fish tank crystal clear. A big advantage of using an external filter is that you can go for much longer without cleaning or replacing the filter media.

It will still give you superior filtration options. External filters also have stronger pumping action than internal filters.

However, external filters are bigger and bulkier than internal aquarium filters. Although you will not have to clean it often, cleaning these filters takes a long time.

Since it has more parts and carries large amounts of filter media, you will have to put aside more time for cleaning.

Nonetheless, external filters are worth the effort and expense because of the superior filtration they offer.

Interesting Further Reading:

What Is The Best Internal Aquarium Filter?

To choose an internal aquarium filter for your tank, you should consider factors like the tank size, type of fish, and budget.

Here are some of the most popular internal aquarium filters for efficient filtration.

1. Fluval U2 Underwater Filter

Fluval internal aquarium filters are a good choice for small tanks. They are compact, sleek, and easily fit into a corner of the tank.

The main advantage of Fluval filters is that they work with a variety of filter media choices. So, you can pick the filter media you prefer. Additionally, they don’t clog up quickly and are relatively easy to clean.

Click here to check out the Fluval U2 underwater filter on Amazon.

2. Aqueon Quietflow Internal Power Filter

The Aqueon Internal power filter is suitable for small tanks with just a few fish. This filter uses suction cups to attach to the wall of a fish tank.

The filter cartridge lasts for up to 4 weeks after installation. It is very efficient at keeping the tank clean and maintaining high water quality. However, it can turn out to be quite noisy.

Click here to check out the Aqueon Quietflow internal power filter on Amazon.

3. Marineland Magnum Polishing Internal Canister Filter

Marineland magnum polishing internal filters are high-end filtration devices. These internal filters not only clean the water but also make it crystal clear.

This filter uses a powerful 3-stage filtering mechanism for efficient and high-quality filtration. You will have to change the filter sleeve and carbon media every few weeks for the filter to work smoothly. It is not too loud either.

Due to its high operation efficiency, you can even use it in turtle tanks which become very messy.

Click here to check out the Marineland Magnum Polishing internal canister filter on Amazon.

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