12 Best Fish Tank Filters 2021

Acrylic vs Glass Aquarium

Anyone who has a fish aquarium knows how important it is to clean the container periodically. Otherwise, it will collect food and animal waste, which is not only unsightly but can also damage the lives of all living organisms within the tank.

It’s important to make sure that your water is always clean and clear, and to make sure you know how to maintain a favorable environment for your fish. Filters are extremely important in removing dirt deposits that will generate ammonia and nitrites (two toxic elements that affect invertebrates).

Filters will also enrich the flow of oxygen and help to create beneficial bacteria that will turn toxic particles into less harmful ones.

These devices can also collect metallic and chemical substances, ensuring the health of the ecosystem and, at the same time, decreasing the frequency at which the water will need changing.

Things to Consider Before Buying an Aquarium Filter

This article will tell you about all the factors that you need to take into account when buying an aquarium filter. We will discuss the different models, the ways in which they work, the right dimension and the cost.


Filtration is done using one of three methods: mechanical, biological and chemical. Devices can use only one type of filter or all three, with the latter being the most effective and most recommended. Apart from anything else, if one of the three filters fail, you will still be able to use the other methods without the need for new investment.

Mechanical filters use synthetic filters (foam or silk) that collect visible particles and any deposited remnants.

Biological filtration is achieved by increasing the volume of oxygen in the aquarium. This creates an environment that is conducive for beneficial bacteria, which convert waste into less toxic substances.

Chemical filtration uses active carbon and resins to extract harmful substances and pollutants from the water. The advantage is that it will thoroughly clean the water, even removing particles that cannot be seen with the naked eye.

Types of Aquarium Filter

There are two main types of filter – external and internal. External filters are more expensive, are more visible and occupy more space, but they are also the most effective.

Internal filters are smaller in size, more accessible and easier to fit, but require more maintenance.

External devices are obviously placed outside the aquarium, they are bulky, noisy and suitable for medium and large containers. They pump the water into the tank and eject it through a pipe or pipe system. There are three external models: the canister, the waterfall, and the wet/dry type.

canister filter

The canister is connected through inlet and outlet tubes, where the first collects the water and leads it to the vessel where the filtration takes place, and the latter drives the clean liquid back into the aquarium.

This action is accomplished by means of a pump, and the advantage of this method is that it can be placed anywhere around the tank. However, it is more expensive.

The waterfall filter hangs on the back of the tank, and is also connected through tubes. This is among the most affordable and versatile, as it allows all types of filtration, and the mode of operation is very simple: a centrifugal pump collects the dirty water, leads it to the treatment chamber, after which it is pushed back through a spillway.

hangs on filter

The wet/dry filter includes an overflow chamber and a tank fitted with the pump. Filtration is achieved through a mixture of water and air, which stimulates the production of beneficial bacteria, maintaining an optimal level of oxygen in the tank. These are among the most effective types of filters, although their price is higher and you may need help in setting it up.

The internal filters are quieter, cheaper and, as can be deduced from the name, they are held by suction cups on the inner walls of the aquarium. By means of a pump, the air currents are put into motion, forming bubbles strong enough to allow filtration. And these, in turn, are found in three different formats: corner, sponge, and substrate.

Internal Filter

Corner filters use compressed air in the filtration process, which is pumped to the bottom of the bowl to remove the dirt. It does not occupy much space, is accessible and easy to install, and is easy to maintain, as you can pick up the whole thing up and clean it separately, then easily return it to the aquarium.

The sponge filter performs biological filtering, and toxic particles can be extracted manually. The dirty liquid is also withdrawn by a pump, but the risk of blocking and clogging is higher than the other models, so it must be removed more often from the water and cleaned to remove the residue.

The substrate filter allows biological and mechanical filtration and is placed between the bottom of the aquarium and the sand/gravel layer.

An air pump or internal filter extracts residues and cleans the water. It is recommended for medium-sized and non-crowded tanks. Planting should be avoided, as the roots can be affected, but if you are really clean to use plants, then it’s best to put eh plants into pots inside the tank.


Capacity requirements is decided by the volume of the aquarium and its density. A high-flow filter is suitable for large vessels, and in this case, an external product is best suited.

For example, at a volume of 50 liters, the filter should have a flow of 60l – 100l (it can be 50 liters, especially if it is not very densely populated, but certainly no less than this).

Moreover, a large number of fish means more waste, so the filter needs to be as large as possible. For very wide containers, you may need both types of filters or at least two of the same category.


The ease with which this is done depends on the model. An external appliance is easy to maintain, and the cleaning can be done every two or three months.

An internal appliance, however, is in constant contact with the dirt and must be removed from the tank for cleaning. To minimize the effort involved, look for a product with pre-filter function.


Costs are proportional to the performance of the filter. But if you do not want to invest a lot of money, and internal device is probably your best bet.

Also, you don’t have to buy an expensive filter if you think you will soon want to change your tank for a larger one. However, try to stay with a trusted brand, as this will save you money in the long run, because this will reduce the risk of the device breaking.

In conclusion, buying a filter is mandatory for all aquariums, but it’s entirely your choice as to which one is right for you.

Buying a filter online is definitely something that we recommend.  Not only is it more convenient, but you will find more deals than in conventional stores and also have the opportunity to learn about the experiences of other users.

Best Aquarium Filters

Below, you will find a list of the most popular aquarium filters available right now:

1. Penn Plax Cascade Canister Aquarium Filter

This filter is made for freshwater as well as for saltwater fish tanks. This wide range of conditions is why so many love this product and are loyal to it. Different types of aquariums in up to 200 gallons are available with this canister filter.

Check Price on Amazon

The product provides a remarkable water flow of 350 gph during operation. Just ensure that you maintain it well so that it works effectively and efficiently.

With a simple button press, the product easily starts and it has a rotation of 360 degrees to better filtrate the tank. With a big filter tank, you can use the system for a long time before needing to substitute it.

It is a trustworthy brand that you can count on when you hurry. Do your fresh and marine aquariums need clear water? Well, this fish tank filter comes with 3 cleaning processes;  mechanical, biological and chemical filtration.

The floss pad removes toxins and impurities from your water, to make it cleaner and more sanitary for your fish and any other aquatic life, by using its activated carbon media.

Pros Cons
  • Self-priming pump
  • A lot of media storage
  • Close to silent
  • Easy to clean and maintain
  • Uses the 3-stage filtering process
  • Some of the plastic parts a little flimsy

2. Fluval Canister Filter, FX6 Filter (400 Gal)

When the canister is filled with water, the filtration system is automatically started. To start the product, no water siphoning is necessary.

Check Price on Amazon

It has a drain on the base of this model. The purpose of the valve is to help empty the canister, making it easy to maintain. In order to send several streams of filtered water to various corners of the aquarium, the spout attached to the system can be adjusted.

The intake is wide and circular and this function helps to siphon more water more quickly.

The FX6 uses six filtering stages! Each basket was designed with precision to stop the bypass of any water. This results in an efficient process of filtration.

Maintenance is very easy and great if you are not good at keeping up with your maintenance. The monthly dial will help you keep in mind the exact date of your last maintenance and change in water.

The FX6 Fluval is a filter beast. It’s a top filter system and utilizes cutting edge aqua technology. You can rely on this filter to last for a very long time; it is durable and reliable.

Pros Cons
  • Very easy to set up with it’s self-priming Smart Pump
  • 6-stage filtration
  • Holds a lot of media (the kit includes media)
  • Durable and longlasting
  • Multi-directional output hose
  • Very, very quiet
  • Expensive (although the price is justified with the advanced technology)
  • Takes up a lot of space compared to the other filters

3. Fluval C Power Filter

The Fluval C4 Power Filter is a rear-mounted filter which works as a filter box. It has a modular media section design, which allows one part of the filter to be switched off or cleaned and it holds much more media than other HOB filters. It’s also easy to customize your own media with its modular design.

Check Price on Amazon

The C4 features a five-stage filtration system (two mechanical, one chemical and two biological) for the selection and filtering of particles.

This filter can produce extraordinarily clear water together with a high flow rate that keeps your fish healthy and happy.

Pros Cons
  • Multi-stage filtration
  • Runs quietly
  • Uses the entire canister volume to increase filtration
  • Quick-change media
  • Noise can be a bit hard on the ears
  • Expensive replacement parts

4. Marineland Penguin Power Filter w/ Multi-Stage Filtration

Not everybody needs or has a budget for an aquarium filter that is as powerful as our top choice filter. The quality may not quite conform to the standards of our number one choice, but for tanks with up to 80 gallons, this provides simple and efficient filtration.

Check Price on Amazon

The Marineland E Rite-Size Filter cartridge is included, but you can use your own selection of media if you prefer, or add additional media to suit your needs. This filter is also equipped with a biological filtering “Bio-Wheel”. This will last for the duration of your filter’s life and must never be changed.

Pros Cons
  • This aquarium is priced at an extremely respectable price.
  • This particular filter is best suited for smaller aquariums.

5. Fluval External Filter

This filter offers superior filtering. It is ideal for all makes and sizes of aquariums, and works for freshwater or saltwater aquariums.

Check Price on Amazon

The powerful engine technology helps speed up the process of filtration. These different features make this product much better than its competitors. To make the product function as required, you simply need to follow the easy set-up instructions.

This product works calmly, with fewer vibrations than other filters and would suit those who are concerned about noise. The multi-stage filtration process promises high quality and cost-effectiveness.

Pros Cons
  • Multi-stage filtration
  • Runs quietly
  • Uses the entire canister volume to increase filtration
  • Quick-change media
  • Instant prime feature
  • Adjustable input/output heights
  • Comes with media
  • Shaky output nozzle

6. EHEIM Classic External Canister Filter with Media

The product has a ring that holds the product tightly sealed while working in the aquarium. You don’t have to worry about leakage which has been reported with other fish tank filters.

Check Price on Amazon

This filter is fitted with filter sponges and other loose filter media, making it easy for the product to work. The device includes many accessories, such as a spray bar, hose, pull-in and many more.

Enjoy a constant circulation of water and an improvement in systemic oxygen during the water purification. Your fish will enjoy filtered waters with this easy-to-use compact sized fish tank filter.

You can easily find the silicon ring on the head of the pump after cleaning your aquarium. It can be transported easily and lightly, saving time for the most quickly filtrated aquarium process.

Pros Cons
  • Simple durable design that’s easy to operate
  • No media trays mean greater water flow past filtration media
  • Holds a lot of filter media
  • Media is included in the kit
  • Quiet, compact, and efficient operation
  • No self-priming feature
  • Does not include activated carbon

7. MarineLand Magniflow Canister Filter for Aquariums

This is the right fish tank filter for you if you want to be able to thoroughly clean your wide tank filter. Enjoy your multi-stage filter with stackable tables that are easily detachable to ensure that you can provide good maintenance and care.

Check Price on Amazon

This filter can cope with a tank of up to 75 gallons and will help you to create a large saltwater fish community with a reliable water filter that meets your expectations and cleanses the water thoroughly. The fish will live happily in crystal clear water.

Do you have a large aquarium between 30 and 150 gallons? You need a filter that easy to clean, and this filter does this perfectly.

Pros Cons
  • The water quality will be crystal clear if set up is completed properly.
  • The filter foam pads that come with this filter can filter out debris and dirt.
  • This filter is priced in an extremely expensive price range.
  • This aquarium filter can leak from the seams.

8. Aqua Clear – Fish Tank Filter – 60 to 110 Gallons

This is a superb fish tank filter with an efficient filtering process that allows the water to come into proper contact with the filter media.

Check Price on Amazon

This filter has an energy efficient pump which will reduce your long-term operating costs. It is quick and easy to install.

This model is equipped with AquaClear foam, bio max and cycle guard, activated carbon for the smooth functioning of its biological filtration and comes with a 2 year guarantee. This makes this model one of the highest quality water filters in comparison with conventional brands.

Just place the filter into your aquarium water after preparation and customize the water flow to your preference using its medium level strainer.

Remember to remove and replace your filter every month.

Pros Cons
  • Supports aquariums between sixty and one hundred gallons.
  • Includes AquaClear Foam that can help increase the aquarium’s water quality.
  • A two-year warranty is included with the purchase of the filter.
  • This particular filter is somewhat more expensive than similar competitor items.

9. Hydor Professional External Canister Filter

Easy to configure and easy to use. Three steps and you’re ready to go – just tap the self-priming button! The engine is durable and has soundproofing that makes it silent.

Check Price on Amazon

The rectangular form ensures that the filtering process is very efficient. Every tray has a large volume of media, and it sits completely flush against the sides of the tank. This forces the water without circumvention through the filtration media.

All necessary media is included with the kit, except carbon. You get space for 2-5 media trays that allow for multistage filtering, depending on which size filter you choose.

They are designed to reduce back pressure using ball-valve connections. And you can adjust the water flow effectively so that you can have the perfect output for your tank.

When you remove your filter for maintenance, you can shut down the flow.

It has an expandable spray bar, which is really cool. You can adjust the length and position of your tank in the four sections to achieve the best results.

The spray bar allows the water flow to be spread and moved into more areas of your tank.

Pros Cons
  • Efficient, powerful, and quiet
  • Simple to set up and use
  • The rectangular shape holds a large volume of media (media included)
  • Easy to prime
  • Hard to find replacement parts
  • Sometimes water tends to spill out

10. Penn Plax Cascade Hang-on Aquarium Filter

This filter is a heavy duty fish tank filter that guarantees high quality and durability. This product can pump 265 gallons per hour, and is mainly used for aquariums of 100 gallons.

Check Price on Amazon

It is designed to perform powerfully even for long periods of continuous use. You can expect crystal clear water to be delivered to marine as well as freshwater aquariums through this filter system.

The product comes with a ground sponge which removes waste and excess food efficiently from the fish tank.

Pros Cons
  • This particular filter is among the quietest options on the market.
  • There is an adjustable water flow handle on the pump head.
  • Water levels can be distributed evenly with the spray bar option.
  • We didn’t find it very reliable

11. Tetra Whisper Power Filter for Aquariums

Take this 1.3-pound fish tank filter for your special aquarium filtration seriously, especially for small-sized aquariums, because it offers superb performance.

Check Price on Amazon

This filter will do an excellent job for 20 gallons of water. It removes excess food, organic decay and dangerous chemicals and comes with intelligently mounted suction cups or brackets, saving your time.

The filter uses large whisper cartridges with an organic whisper for the intelligently designed three-stage filtration process.

This is not only the right choice for those of us who love filtration, but is also excellent for flexible adjustment of low or high water levels.

Pros Cons
  • This aquarium water filter takes advantage of time strip technology.
  • This filter is great for beginners and advanced aquarium handlers.
  • The reliability record for this fish tank filter is not very good.
  • The noise that this filter makes can be loud and annoying in some cases.

12. Sunsun Hw304B 525GPH Pro Canister Filter Kit

The fact that it comes with a built-in 9 watt UV sterilizer is what makes this filter stand out. This helps kill bacteria and algae spores; it supports crystal clear water.

Check Price on Amazon

The large blue automatic pump works well and avoids the need for manual siphoning. And with four flexible media trays, excellent mechanical, chemical and biological filtration is achieved.

Cleaning and maintenance is very easy, but when cleaning, one thing you must take into account is the order of the racks or replacing the top will be impossible.

It is possible to untie both the input and output tubes at the same time using a useful switch.

In fact, the switch cuts off the water and leaves it in both sides. It’s useful because it will help to restart the siphoning system.

It is necessary to be aware that the flux rate is not controlled by this switch. Stick to it or open it.

The SunSun Pro can stand up to the big names and save you a lot of money. You’re getting a lot of power and it’s resilient and efficient.

Pros Cons
  • Efficient, powerful, and quiet
  • Simple to set up and use
  • The rectangular shape holds a large volume of media (media included)
  • Easy to prime
  • Expandable spray bar
  • If you’re not careful, water can spill out when taking it apart for maintenance
  • Like most filters, the instruction manual isn’t the best.

How to use an Aquarium Filter

An aquarium is a small oasis of relaxation – if it has not already turned into a passion. Today, it’s hard to imagine a functional aquarium without the help of a filter, but there are a number of tricks that you need to be aware of in order to achieve the results you expect.

Assembling the Filter

For space-saving reasons, many manufacturers deliver disassembled filters, and it is your job to put them together, before you can install them in the aquarium.

Generally, the assembly information is so detailed that you shouldn’t encounter any difficulties during this process which only takes only a few minutes. Start by identifying each piece, then the connections between them.

Install the filter

Once you’ve made all the connections between the filter and the rest of the aquarium water purifier, it’s time to actually install it.

In the case of filters placed under gravel, make sure they are positioned correctly, including the piping, before filling the container with water. Also, check that the piping is properly attached to the air pump.

In the case of external filters, mounting is often simpler and installation easier. However, the main concern in this case is that the power supply does not come into contact with water.

Cleaning the filter

Apart from exceptional situations in which the aquarium is particularly dirty, monthly cleaning of the electrical filters is generally sufficient.

On the other hand, if it is a mechanical filter, it is advisable to rinse the membrane and the filter sponge weekly to keep it in good working order. Once these elements are clogged up, it is difficult to reuse them to their optimal efficiency.

Cleaning your aquarium filter – More important information

Cleaning the filter is not something that needs doing weekly with each water change, but only when it can no longer perform its function effectively.

The filter performs 3 types of filtration: mechanical, chemical and biological. By means of the sponge filter elements, they retain a series of particles that are suspended in water, therefore over time, the pores of these filter elements clump and the water can no longer circulate freely through the filter.

Cleaning your aquarium filter

As a consequence, the biological and chemical filtration capacity also decreases, causing harmful substances for aquatic life.

Filter media cleaning is done to restore the mechanical filtration function. The decision to clean it is taken once a marked decrease of the return flow is observed.

External filters (canister type) contain a large number of filter elements (they have a large filtering surface) and require less time to clean.

Conversely, small (internal) filters need to be cleaned more often. If a prefilter is attached to the filter path, it is necessary to clean the filter itself because it stops most of the particles from the water and can be easily cleaned weekly, avoiding complete cleaning of the external filter that is very time-consuming.

As the aquarium cycles, a series of bacteria beneficial to the equilibrium of an aquarium are deposited on the filter materials.

They help eliminate some fish-damaging substances. These bacteria can be easily removed during the thorough cleaning of the filter elements, which is undesirable.

Filter materials do not have to be squeezed.

Filter elements (sponge, polyp, etc.) are extracted from the filter and cleaned in a water tank (preferably water removed from the aquarium). Cleaning is done gently by manually removing visible macroscopic substances.

Avoid squeezing the sponge. It should be carefully cleaned under a gentle jet of tap water, but be careful to not remove a large number of bacteria that colonize the filter in this process. The biological filter elements (rings and ceramic cylinders) are rinsed gently in a bowl with aspirated water from the aquarium to remove visible coarse dirt.

With time inside the aquarium hoses, a number of substances are deposited that substantially narrow their diameter, causing a marked decrease in the flow of the filter. They can be cleaned easily using long cleaning wipes.

Cleaning the filter will not involve using soaps, detergents and other substances of this nature. Cleaning the filter, as mentioned above, is about removing the dirt that mechanically clogs the filter media, so delicate rinsing is sufficient.

Using UV as a method of keeping the water clean

Using UV lamps – Are they better than UV filters? Are they efficient and safe?

UV light sterilizers are used for aquariums to help eliminate algae, parasites, and unwanted bacteria. Light from UV lamps alters and disrupts the cellular structure of harmful algae and bacteria, thereby destroying their reproductive properties.

Eliminating them from the aquarium is made very easy by the UV filter since all the water that reaches the aquarium will pass through it eventually. Most people install the filters so that the water supply passes directly through the sterilizer. The system has UV lamps that will light as the water passes through it.

It is important that when choosing a sterilizer with UV lamps, choose the right one for the flow rate and the size of the aquarium to which it will be installed, otherwise, the filter will not work properly and the bacteria will not be eliminated.

It is also possible to find an aquarium that has already installed the optimum filter for its size and flow, so manufacturers are trying to help their customers.

Installation of sterilizers with UV lamps is more common for marine-based aquariums than for freshwater aquariums. Often in freshwater aquaria, different beneficial algae are planted that use all the resources available to them to destroy any trace of bacteria, parasites, and algae that could affect the aquarium ecosystem.

You must remember that sterilizers with UV lamps do not differentiate between beneficial and harmful algae so they will destroy any plant that enters their range.

If you plan to use such a filter and you do not want to kill any of the free-floating planktonic animals such as amphipods or copepods, then you should buy a filter that you can set to act only when the light is out, as they tend to hide in the day.

Sterilizers with UV lamps can have a negative or neutralizing effect on the treatments you add to aquarium water, so be sure to stop the filter if you treat fish with different chemicals.

The last thing I want to add is that the UV lamps of the sterilizer should be replaced every 6 months, which is a cost that you need to consider when deciding to buy such a product. A UV lamp should never be used for longer than the recommended time, as this is very dangerous for both your fish and you.

Finally, I would remind you that for a freshwater aquarium there is no need for a water filter, although it is still recommended to install one.

In the case of marine aquariums, the situation is changing: a UV lamp sterilizer is an accessory that you cannot ignore if you want to have happy and healthy fish, but you have to be very careful to choose the right filter for your aquarium size, otherwise you will do more harm than good.

Why it is Important to Have a Filter in Your Fish Tank

Inevitably both fish and other aquarium organisms eliminate metabolic products into the water that can negatively influence its quality, and if these substances are ignored, they can lead to the death of the fish.

Filtering is absolutely mandatory in an aquarium. It provides optimum water for life, and also clear and clean water which enhances aquarium illumination, making the tank all the more appealing.

Filtration is the process by which the suspended components are removed from the water, otherwise, the water will be cloudy and repellent. Depending on how these particles are removed, there are three types of filtration:

  • Mechanical
  • Biological
  • Chemical

Physical filtering can be done by both internal and external filters. It passes the water through a series of filtering materials, which are increasingly finer and will retain the particles in the water like a sieve, then allowing the water to resume its circuit in the aquarium.

The most used filters were the so-called “wobbly filters” but they gradually lost ground to the better designed filters. They are made up of a sponge with outer strips and a hollow inside that will insert a loudspeaker with a hose connected to an air pump.

Thus, the air will rise rapidly and create a low pressure inside the sponge to equalize the pressure, the aquarium water will enter the sponge body where the particles will be retained in the water.

clean fish tank

After a few days of operation, the sponge is removed from the aquarium, washed until the water passing through it comes out clear and clean and then reintroduced into the aquarium. This type of filter is very simple but has its drawbacks; it is unsightly and does not have a very high yield.

Another example of the filter type is the internal filter, it is a device that works on the same principle but has a higher efficiency because, being electrically driven, it can filter a much larger volume of water.

This type of filter is very commonly used and is currently the most popular choice of filter for personal aquarium owners, being a relatively inexpensive, high performing variant for aquariums up to 150 liters. As in the previous example, this filter should be washed regularly, otherwise the pump will not be able to provide an equal flow and the filtering is aggravated.

Other types of mechanical filters can use sand, gravel, cotton, sponge, active carbon or other natural or synthetic porous media as filter media. They can be made quite easily by a person who understands the principle of operation (photo) from a simple aquarium.

This must be done in such a way that the water in the aquarium passes through a series of filter media and returns to the main aquarium.

The flow of water can be done by means of an internal filter head (i.e. the engine box). This type of filter is very efficient and inexpensive, is easy to maintain because, unlike others, it does not require frequent washing of filter media.

Filtering media must be arranged so that it is finer, starting with gravel and ending with cotton, but there may also be a single filter medium, for example, just cotton, but it must be compact to make it more efficient at filtering.

These filters must be located near the aquariums they will filter and must be masked so as not to disturb them aesthetically. They can be incorporated into the furniture or in the wall, but they must be easily accessible.

Biological filters are those filters that, in addition to retaining particles in the water, provide light and heat, beneficial to the development of algae and bacteria.

These algae colonies will use the ammonium ions and phosphatic salts, which would otherwise damage the aquarium, for their own development.

A biological filter variant is a filter located above the aquarium, made of a PVC gutter inside which are synthetic fibers or sand and which is provided with a multitude of holes that allows for the circulation of water. Once past the filter, the water will be released from the suspension components and will fall freely in the aquarium in the form of rain.

Organic matter encounters numerous aerobic bacteria in the filter material that will mineralize it. Algae plays an important role in providing oxygen through the photosynthesis process and the use of components decomposed by aerobic bacteria such as ammonium ions and phosphate salts for their own food.

Partial water treatment can be done relatively simply with a so-called former. This extremely simple installation is based on an air pump and a loudspeaker. Pressurized air through a tube causes an intense stirring of the water, which causes the formation of highly charged white foam and colloidal substances. This greenish foam is then picked up in a cup and removed.

UV radiation filtration is used in marine aquariums and ponds to reduce turbidity, this radiation is fatal to micro-organisms, and if treated, they are killed and water is practically sterile.

But this type of filtration has drawbacks as it neutralizes important microelements for plants, one of which is iron. However, it is recommended for use after a drug treatment because it decreases or even cancels the action.

The choice of filtration method must be made in consideration of several factors in order to achieve crystal clear water and a healthy aquarium:

  • the number and size of the fish;
  • the volume of the aquarium;
  • fish species and aquarium plants;
  • type and amount of fish food;
  • The amount of fertilizer in the water.

Regardless of the filtering method chosen, it is good for each aquarium to be refreshed each week by removing 25-30% of the water and adding the same amount of fresh water.

FAQ Section

How often should you clean an aquarium filter?

It is recommended that you clean your aquarium filter once every 2 weeks. It is important to keep it in the right shape and condition in order for it to work properly.

Should an aquarium filter always be on?

Yes, filters should always be working. It is important to keep constant water flow into your tank in order to avoid fish diseases and unbalanced water parameters.

Can aquarium filters be turned off at night?

They can, but we don’t recommend it. It is important to leave them working at all time.

You can choose from different variants, but most often you will find models that are mounted with suction cups on the corner of the aquarium.

They pump compressed air to the base of the pool, so the residual particles rise to the surface and you can easily gather them with a net. If you install them correctly and position the pump very close to the surface of the water, the nozzle forms a spring of water and facilitates aeration.

Other models also sprint, with the help of a pump, a subtle water movement that passes through absorbent sponges. Waste is retained inside, but you need to clean or change it regularly.

Some filter cameras are modular so you can introduce different cleaning materials to complement each other. Many reviews about the best and cheapest aquarium filters suggest that you should choose one that combines biological and physical filtering.

Always take into account the capacity of the aquarium and the needs of the fish you care for. Typically, manufacturers specify the maximum volume of water that the product can handle. Depending on this, the maximum filter flow rate also varies. For example, for a pool of over 120 liters, you will need a 700l/hour flow.

The smaller the aquarium, the lower the flow. Always adjust it, depending on the water volume and the sensitivity of your fish. Do not try to clean faster, at a higher rate, because plants and animals will suffer.

Also, if you recreate small animal or insect living conditions, and the vessel integrates micro-beaches and specific vegetation (as happens when you decorate terrariums), choose a suitable model for the depth of water in the micro-universe you’ve organized.

Saurabh Kumar

I am a passionate fish keeper, with years of experience. You will find some really useful tips and information on this blog about Freshwater Aquariums.

Recent Posts