🥇[TOP 10] Best Filter for 20 Gallon Aquarium Reviews in 2021

Do you have a 20 gallon aquarium that needs to be filtered? Have you been having trouble picking out the best filter for your tank? This blog post is for you! In this article, we will go over some of the most popular filters and what they are used for. We’ll also talk about how often these filters need to be changed. Let’s get started!

What Type of Filter to Choose Best Filters for 20 Gallon Aquarium?

Hang on Back Filter (HOB):

is the most common filter system in aquarium. It consists of a separate reservoir with pump located outside the tank and a return nozzle at the back of the tank on which media is attached to provide filtration using water from the tank. Depending on your need, you can choose between Single Stage or Two-Stage Hang on Back Filter (HOB).

Internal Filter:

internal filters are submerged in water and may be attached to a tank, or freestanding in an external filter. They pump water into a filter where it travels through various types of media before returning to the tank.

Internal filters range from simple to complex. The simplest and least expensive type is the sponge-type unit. These use very little media, since the media itself is not contained in a separate casing. Most of these have large openings so that they can be wedged into an ordinary tank or bucket. This helps keep the cost down because there are no special cases to buy.

Filters with cannister:

are designed for tanks up to 40 gallons and work by drawing water into the cannister. The water is then pumped through internal filter media that removes debris and dirt thus making it cleaner before the water returns to your tank.

Filters with canister:

Canister Filter are prefered by many people on small tanks because of their ability to create a large amount of biological filtration for their size. Although the initial setup can be a little bit more tricky, the added benefits of having a large biological filtration capacity in such a small space makes this filter worth the trouble. Canister filters have some very attractive features that make them ideal for smaller tanks:

What is The Best Filters for 20 Gallon Aquarium?

 Polar Aurora Free Media Check Price on Amazon
 Aqueon Quietflow Canister Filter Check Price on Amazon
 Cascade Canister Filter Check Price on Amazon
 Fluval 07 Series Performance Canister Filter Check Price on Amazon
 Aqueon Quietflow Internal Power Filter Check Price on Amazon
 MarineLand Magnum Polishing Internal Canister Filter Check Price on Amazon
 Fluval U Series Underwater Filter for Aquariums Check Price on Amazon
 Fluval C Series Power Filter Check Price on Amazon
 GRECH CBG-800 5W UV Sterilizer Hang-On Back Filter Check Price on Amazon
 AquaClear Hagen Power Filter Check Price on Amazon

 Best Filters for 20 Gallon Aquarium Reviews

Polar Aurora Free Media

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Fresh from the engineering laboratory of SunSun, this media is quickly becoming a favorite among pet parents worldwide. With adjustable spray bars and self-priming pumps, you can ensure that your fish tank will be nice and clean without hassle.

Includes 3 trays suitable for use with any type of filter media you prefer including pre-filter sponge, bio resin or compressed peat moss to help extend the life of your fish tank by removing harmful residues from aquarium water surfaces.

Fully aquarium safe interior parts are made out of plastic as well as stainless steel so you don’t have to worry about any corrosion affecting its working properties; these filters are available in both 1/2″ and 3/4″ hose size with an adjustable output flow rate

The triple canister filter by SunSun is a fantastic option for any aquarium owner of the Freshwater, Marine, or Reef setup. The three flexible trays work to ensure that you always have your filtration media ready, while also giving them plenty of space in order to allow optimum flow and performance at all times. With its high water pressure system and durable design it will more than please the fussiest aquarists out there!

Aqueon Quietflow Canister Filter

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Why tinker with your tank and filter when the professionals, at Aqueon, can do it for you? The Aqueon Quietflow Canister Filter has all of your bases covered. It is designed for both freshwater and saltwater aquariums of up to 55 gallons. Included is a unique hang on the back water polishing unit that makes maintaining your aquarium filter quick and easy! If some traditional naquarium water return method is preferred, such as spray bar or water director, connections are included in this product to accommodate. Quit trying to balance chemicals when you should be spending time enjoying nature’s beauty: let Aqueon’s Quietflow Canister Filter take care of everything for you!

The Aqueon Quietflow Canister Filter is perfect for home aquariums requiring more advanced filtration than a hang-on filter can offer. Constructed of heavy duty plastic, it boasts an advanced design that delivers precise water flow control with minimal noise. The preloaded canister includes the necessary media to keep your fish swimming in clean and safe water at all times: Bio Balls, Coarse Foam, Activated Carbon, Bacteria Rings (Bio Ceramic) and Clear Wafers—ensuring fewer cleaning cycles due to waste buildup! Make the Aqueon Filters’ tank ornaments look even better by adding one of our stylish decorative backgrounds.

Cascade Canister Filter

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The secret to a happy and healthy freshwater tank is the clean pure water. Now make your job keeping up with this easier by investing in an effective filter system from Cascade, which doesn’t just remove impurities but also contains helpful bacteria for the health of your fish. Forget those low quality devices that clog or break down over time. This commercial grade aquarium filter canister has independent 360 degree rotating valve caps so you’re never stuck wrestling with difficult twists, plus it comes with a push button self-primer so there’s no more struggling getting it going for another day of work when all you want is to enjoy your favorite hobby!

The Cascade Canister Filter is a sturdy hydration system that will keep you alive in the wilderness. With this filter, you can drink from all of your favorite lakes and streams, while maintaining a healthy balance of essential minerals like magnesium and calcium. The four-inch diameter intake hose is perfect for filling camping water bottles by simply hanging them alongside the top handle. The design is thoughtful with easy flow rate cut-off valves to control water flow when filtering before filling containers. And don’t worry about setting this baby down on the ground; it has a tip-proof base!

Fluval 07 Series Performance Canister Filter

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The Fluval 07 Series Performance Canister Filter is the perfect addition to your aquarium to keep water naturally clean, clear and healthy. Activated carbon removes impurities before they break down into harmful compounds like ammonia and nitrates. Tthis canister filter provides superior chemical filtration that successfully eliminates odors, discoloration and unwanted substances in tap water before these lead to rapid growth of problematic algae or organic sludge buildup in the tank. It features a manual drain function so you never have to risk getting wet when cleaning this system.

The Fluval 07 Series Performance Canister Filter is made with a revolutionary ergonomic design and raised lip for smoother operation. With its new center handle, our canister filter breaks the mold by allowing the main media stack to be removed without taking off our lid! You no longer have to deal with those time-consuming pumps that you have to engage in order to insert or remove any portion of your canister filter. The 07 Series also comes equipped with single action dual locking clamps which allow quick release and attachment of hoses, as well as special design features that offer less pump strokes when engaging or disengaging flow rates.

Don’t settle for a run-of-the-mill filter, because you deserve the best. The fluval 07 series has been called “provocative and innovative” by our team of experts in marine life. It offers unmatched self-priming ultra quiet operation at an EPA Energy Star rated efficiency. We love it because you can enjoy up to 75% less energy consumption than comparable filters on the market. This is one product that will make your fish thank you. You’ll never have to worry about electricity bills again!

Aqueon Quietflow Internal Power Filter

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The Aqueon Quietflow filter is a sleek and powerful choice for you aquariums. It provides three stages of filtration: mechanical, chemical, and biological to clean your tank’s water well. This quiet, submersible filter is easy to install in either a vertical or horizontal position and has an adjustment knob that controls flow rate during the water return process. With this aesthetically pleasing device for your fish tanks, you can rest easy knowing they’re getting fresh filtered oxygenated water every time you turn it on!

This internal power filter provides superior filtration for your aquarium while producing barely audible sound levels. The water flow can be adjusted in two different directions with the directional spout and height-adjustable splash guard, giving you complete control over how much or little water returns to the tank. Comes fully equipped with an Aqueon Replacement Internal Filter Cartridge, which remove bad odors as well as pet dander that may spoil your fish’s mood. With this talented device on duty, you won’t have to worry about a thing!

MarineLand Magnum Polishing Internal Canister Filter

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Clean out as little as a quarter of your aquarium’s dirt and debris – with one filter. Designed to replace an aging canister filter, the MarineLand Magnum Polishing Internal Canister Filter has two media compartments – making it easy to switch between carbon or custom media inserts for added filtration in need. The deeply-submerged motor provides quick startup, plus access to undersurface water areas that would be difficult with an external filter. Micron water polishing makes the clean-out process even more efficient, while easy sloped surfaces make adding new aquatic life simple. Big on power but convenient for you, there really is no reason not to take this step today!

The Marineland Magnum Polishing Internal Canister Filter is a great filter for aquariums up to 97 gallons because it filters 290 gallons of water per hour and includes the Marineland Ml90770.

The Magnum Polishing Internal Canister Filter installs easily on an outside wall or inside the tank with minimum plumbing required, so expect minimal noise (if any!) and easy filtration. The cartridge works best in freshwater or marine saltwater aquariums within a pH range from 6-8, and will remove all impurities such as fish waste, haircoat particles, medicines used against parasites, detergents used to clean equipment–in short: Anything that can cloud up your home’s little underwater window into the natural world.

Fluval U Series Underwater Filter for Aquariums

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The Fluval U Series is an excellent decorative under water filter to keep your aquarium clear and healthy. The Fluval design takes a revolutionary, 3-stage approach to filtering your water more than twice as fast as other brands. It uses what they call the “Efficient Cleaning System” with Vortex cleaning rings to filter debris from the surface of the aquarium, a tight fitting brush under the reservoir that traps coarse dirt particles, and large Pleat Filtration Grids for trapping fine particles. Now easier than ever before it’s time you take care of your new aquatic family!

Fluval’s new U Series is the perfect choice for fresh or salt water aquariums of any size. The Fluval U Series includes a sleek, high-performance canister filter in three standard sizes: 10, 20 and 30 gallons. What sets the Fluval undergravel filters apart from other brands? Unlike tanks with densely packed media, these powerful units deliver superior oxygenation with premium grade foam that traps more debris than ever before. The redesigned media cartridge holds more coarse foam than traditional cartridges to allow for greater surface area contact between water and filter material to dramatically improve filtration performance in smaller spaces – 10 gallons or less – while strong diffusion plates still maintain efficiency in larger tanks like outdoor ponds up to 300 gallons.

The Fluval U Series aquarium filter is designed for water filtration across a range of applications and terrariums. Whether you have a saltwater tank, freshwater environment or even keeping tropical fish, this filter can be used in any type of setup with ease.

A customizable design lets you choose to have the product hang vertically against your wall (perfect for creating currents), set it horizontally on the bottom of your tank if its shallower than 20 inches deep or use it as an under-the air pump to keep your reptile’s cage clean and healthy.

Fluval C Series Power Filter

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Fluval’s C Series Power Filter is the simplest way to build a healthy freshwater or saltwater aquarium. With its patented five-stage design, it effectively traps large and small debris from your water while foams easily slide out for quick cleaning. This power filter accommodates tanks between 20 and 50 gallons.

The Fluval C Series Power Filter provides an unbeatable combination of performance and ease of use. Chemical, biological, and mechanical stages work to filter pool water at every level while Bio-Screen eliminates the chance for debris and bacteria to accumulate around your pump basket or skimmer. With a unique design, you’ll never have to replace the impeller again with this self-priming system that operates close to suctions potential pressure limits for cleaner more efficient operation.

Plus, when loaded with Fluval C-Nodes, the Biological Trickle Chamber is super charged for fast and efficient nitrification, which means less routine maintenance for you! Get sparkling clean water faster than ever before with this great product from Fluval.

GRECH CBG-800 5W UV Sterilizer Hang-On Back Filter

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The Grech CBG-800 5W UV Sterilizer Hang-On Back Filter is the ideal choice for an aquarist that has a 20 to 50 gallon tank. The adjustable 211gph filter flow rate with surface skimmer eliminates undesired surface films and helps eliminate algae and bacteria keeping aquarium water crystal clear. To finish it all off, this product has an added 5 watt UV sterilizer which effectively kills and removes many types of microorganisms including dangerous pathogens like ich which can be fatal when ingested by fish or used as bait!

The Grech CBG-800 5W UV Sterilizer Hang-On Back Filter offers a multi stage filtration mechanism. Keeping the water clear and healthy is easy with this biological and mechanical hang on back filter. They make a strong addition to any aquarium, pond or water garden application! Box includes Active Carbon and Bio media. Note: Impeller may be stuck due to magnet attached after sitting in original box for long periods of time. Give it a little push right out of the box to start as magnet can sometime get caught when it “sits” too long during storage.”

AquaClear Hagen Power Filter

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Installed easily and efficiently, the Hagen Power Filter for AquaClear Aquariums has been designed to filter your tank in a professional manner. The patented design offers maximum contact time with filter media so that you never have to worry about clogged filters again.

The high efficiency pump operates smartly with the use of less energy for more power. So go ahead and stock up on fish treats knowing that your filtration system will be fully up-to-date while saving money as well!

Reliable operation from trusted brand who is out to provide you with quality products and accurate customer service. Not only does this product offer superior performance but it’s durable too–it can withstand accidental drops (up to 7 ft).

Say goodbye to terrible fish tank water, with the power of AquaClear. The Hagen Power Filter contains all the main types of filtration. It comes equipped with a foam, activated carbon filter and biomineral for cleaner aquariums. This product is perfect for aquariums up to 30 gallons, and will make everything from replacing your old filters so much easier! With Aqua Clear’s lifetime warranty there are no worries about breaking or damaging this product either.

The professional tones in our descriptions give you reassurance that we care about your pets health because it means clean and safe water sources for them to enjoy as they grow older!

Why is an Aquarium Filter Important?

The Nitrogen Cycle:

The nitrogen cycle in an aquarium is a process of converting ammonia, nitrite and nitrate into harmless substances, like oxygen (O2). It’s the processes that takes place in your aquarium to convert toxic waste materials into forms that are not harmful for the fish. The nitrogen cycle can be found in all living things on earth but it exists in varying degrees of complexity. In a nutshell, it involves the bacteria that are present in your aquarium and how they interact with one another to convert harmful substances into harmless ones.

Why I Don’t Recommend Filter Cartridges:

If you’re a beginner to the world of fish keeping, it’s likely that one of the first things you’ll purchase for your aquarium is some sort of filter. It’s easy to understand why; people just assume that as their aquariums need water and air so they also require something else to keep them clean. In truth, while filters do have their place in some aquariums, many of them are unnecessary and even detrimental to the fish’s health. I’m talking about filter cartridges.

Filter cartridges are essentially sponges that have been treated with specific chemicals and then sealed inside a plastic housing. The idea behind them is fairly simple; the sponge will develop a colony of beneficial bacteria which will then consume any waste materials that are present in your aquarium’s water. The problem is, however, that filter cartridges have a very limited lifespan and if you forget to replace it on time and the bacteria inside runs out of food (which happens sooner than you’d think) then the fish could die within hours.

The only way you can get around this is by using a filter that’s specifically designed to run without these cartridges. These are much more expensive than regular filters, but the extra expense is well worth it! There are two different kinds of filter you can use in your aquarium; they’re internal and external filters.

Internal Filters:

Internal filters are attached directly to your aquarium and work by pumping water through them. They’re a lot like air-conditioning units in that they have to be cleaned regularly so the filter doesn’t become clogged with dirt and bacteria but other than that, do very little apart from move the water around. Internal filters come in two forms; power filters and bubble filters.

3. Biomedia:

The purpose of Biomedia is to provide a safe environment for beneficial bacteria to live and grow so they can help your tank cycle. As mentioned previously, the filter in your aquarium will only be as effective as its colony of good bacteria and that is why it’s essential for you to stock up on biomedia when you’re setting up your new tank and filter.

Biomedia can come in the form of cut up plastic bags or ceramic noodles. Both have their downfalls, with the plastic bag being too porous and allowing bacteria to escape into the main water column while making it difficult for them to attach themselves, and ceramic noodles be unable to provide a big enough surface area for bacteria to grow on.

GPH and Why It’s Important:

The General Pump Rate (GPM) or Gallons Per Hour is the speed at which water passes through a filter, expressed in gallons per hour. GPH is measured by inserting a special U tube into the output of your filter and timing how long it takes for the water level to rise one inch. This is an important thing to know because no matter what size filter your aquarium requires, it’s going to have a minimum GPH that it needs in order to function properly; less than that and you’re just wasting money on electricity!

Filtration Rating:

When choosing a filtration rating, it’s important to note the difference between your aquariums maximum and minimum capacities. If you have an all-in-one desktop aquarium that has a 10 gallon capacity, for example, it would be unwise to purchase a filter rated at 5 or 6 GPH as that wouldn’t be enough to keep up with the water being added when the filter is over-watered. The same is true when choosing a filter for your fish tank; you want to ensure that it will be able to handle the entire volume of water in your aquarium with no problem at all, especially if you’re planning on getting larger or more active fish in the future!

See more: https://memfish.net/best-heater-for-20-gallon-aquarium

Frequently asked questions:

1. Do I need a filter for my 20-gallon aquarium?

The simple answer to this is “Yes,” but before you start looking at costs, you’ll want to decide on a few things. Are you going to keep live plants? Will your fish be able to handle strong current? How bad are the nitrates in your tap water? All of these play into how much filtration power will be required and what size of a filter you’ll need.

2. Are filters dangerous for my fish?

If used correctly, they really aren’t. However, some manufacturers make faulty products from time to time. No matter how safe or popular the unit is, always read the packaging carefully before setting it up. Certain filtration units should not be used if you have live plants, invertebrates or fish that are sensitive to strong currents.

3. How do I choose a flow rate for my 20 gallon aquarium?

Flow rates should be based on the total amount of water in your tank. Some filters have pre-programmed settings with gallons marked (5, 10, 15, etc.). Remember that the gallons marked are based on water, not fish or substrate (if using substrate). So if you have a 20-gallon tank with only 5 gallons of substrate and a few gravel rocks, it would be best to use the 10-gallon setting. If there are no preprogrammed settings available, try this formula: Flow rate (GPH) = (total water in the tank) / ((tank length at the deepest point) x (tank width at the widest point)) For example, if you have a 20-gallon aquarium with 10 inches of substrate and a 7 inch wide gravel bed: Flow rate would be: (20 gallons total water volume)/((20 x 7) x (10 inches of substrate)) = 15 GPH flow rate

4. What filter should I get for my 20-gallon aquarium?

This is also a difficult question. Generally speaking, you don’t want to choose the cheapest filter on the market and be left with an ineffective product that doesn’t do its job properly. You can also throw money out the window if you choose a filter that’s too powerful and ends up over-filling your tank. There are three major types of filter media used, each with its own strengths and weaknesses: Mechanical filtration – uses mechanical means such as foam or activated carbon to trap debris.

5. Can you use a 30 gallon filter on a 20 gallon tank?

You can, but you’ll need to reduce the flow rate if it is a power filter.

6. How many GPH does a 20 gallon tank need?

This depends on the type of fish and invertebrates you plan to keep in your tank. Most aquarium sizes are based on these two metrics: Length x Width = Gallons of water. This is where flow rate comes into play.

7. How long does it take to filter a 20 gallon tank?

For most aquarium systems, about 5 minutes per hour of fish capacity per hour is recommended for small tanks and 3x this amount in large tanks. So if you have a 20-gallon tank with three 8-inch fish, you’ll need a filtration rate of approximately 2×5 minutes per hour or 10 minutes per hour.


The best aquarium air stone for sale is a product that does as it says and helps to provide your underwater inhabitants with oxygen. There are many products available, so we recommend you do some research before making your final purchase decision. Mem Fish have done the work of sifting through all these options for you and found 3 great choices below which offer different features to suit every need! These are good products that you should choose to buy.

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