In this article, we’ll help you find a good HOB filter for your 20 gallon fish tank, share a few tips and tricks to help you find the right filter for your specific needs.
Keeping fish is fun. But it’s also a responsibility.
Your fish need to be fed, the fish tank needs to be set up just right, and the water needs to be cleaned.
Leftover fish food and waste produced by the fish shouldn’t accumulate in the tank; otherwise, the water will get too dirty for your fish to keep healthy.
There is some manual cleaning involved in maintaining a fish tank, but the bulk of cleaning responsibility falls on the filter.
The filter is one of the more critical elements of the setup since it is directly related to the health and well being of the fish.
When selecting a HOB filter for a 20 gallon aquarium, I typically like to think of what fish I’ll be stocking in this tank.
For example, will it be densely planted or heavily stocked?
All of this matters when selecting the right filter. A densely planted tank won’t need much filtration as your plants will help filter the water.
However, a heavily stocked tank may require you to select a filter that is rated for a 20 or even a 30 gallon tank depending on what you keep.
I set up a 10-gallon tank with lots of plants, six glowlight tetra a few shrimp. For this tank, I used an Aquaclear 20, and the water always looks great.
Next, let’s take a quick look at four power filters that would be great for a 20 gallon tank.
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Here Is My All-Time Favorite Hang On The Back Filter
What Is The Best HOB Filter For A 20 Gallon Tank?
Here are 4 of the best hang on the back filters you can choose for your small 20 gallon fish tank:
One-size-fits-all fish tank filters don’t work equally well with different aquariums. AquaClear has understood this issue and designed its filters for different tank capacities and filter rates. Here, we are reviewing this filter that is perfect for 20 gallon tanks but can be used with the sizes up to 50 gallons. The AquaClear filter has a pump output of 200 gallons per hour that ensures the right amount of water circulation.
One of the most impressive things about this HOB filter is its filtering mechanism that is different from traditional cartridge filters. The manufacturer has used a patented multi-stage filtration system called CycleGuard. It consists of a foam insert, an activated carbon filter insert, and a BioMax filter insert that is made of ceramic rings.
This well-thought-out filtration system delivers optimal chemical, biological, and mechanical filtration but without removing good bacteria from the water that act as nitrate and ammonia exterminator in the water. With cartridge filters, you can’t protect and grow these beneficial bacteria colonies that contribute to making the aquarium environment safer for fish.
The AquaClear HOB filter comes with a lifetime guarantee for non-replaceable parts. Also, if you are cleaning the filter every other week and replacing its filters inserts within the prescribed time, you can use it with any aquarium throughout its operating life.
- Features a re-filtration system— control the flow rate without compromising on filtration efficiency
- Its gentle flow pattern is ideal for delicate plant and fish species
- Filtration volume seven times larger than other similar filters
- Offers best biological filtration for aquarium— doesn’t get rid of good bacteria
- Makes a loud noise with its motor’s movement
- 2-week cleaning might not suit some users
- Costly to replace filters inserts after a couple of months
- Prone to leaks
2. Marina Power Filter
This product by Aqueon can be a top pick among the HOB filters for 20 gallon tanks. Nearly every feature of this fish tank filter is great and worth discussing. For starters, its multi-stage filtration system doesn’t just include chemical, biological, and mechanical filtration. The manufacturer has also used its propriety filtration pads to ensure a holistic cleaning of the water.
The other great thing about this Aqueon fish tank filter is its tremendous flow rate. When many similar filters offer 100-200 gallons per hour, Aqueon QuietFlow can circulate 400 gallons of water in an hour. This high flow rate ensures better oxygenation of the aquarium water that keeps the aquatic life active and healthy.
Aqueon has used the title “QuietFlow” for this filter for a reason. Its internal pump is designed in a way that it dampens the noise of the motor and impeller. The design is also leak-proof, so you don’t have to worry about a puddle of dirty water around the aquarium with drip-drip leaks that often happen in substandard HOB filters.
Another feature that makes it stand apart among other HOB filters is its LED indicator light. Instead of keeping track of days and weeks, you can find out when it is time to replace the cartridges with this LED indicator that starts flashing when cartridges get clogged.
- Offers noise-free operations— one of the quietest filters on the block
- Easy to install and set up— features a self-priming pump
- Features an LED indicator for hassle-free cartridge replacement
- Comes with a lifetime warranty
- The impeller shaft can seize due to dirt/grease accumulation
- The plastic filter chamber construction could be better
- Impeller might rattle against the glass
- A bit heavy on the pocket
4. Marineland Penguin Power Filter
Marineland has been making fishkeeping accessories for more than 40 years and is known for its quality products. Its Penguin Power Filter is also a top HOB filter for 20 gallon tanks. You can get it in five sizes for different flow rates going from 75 gallons/hour to up to 350 gallons/hour. Like any top-of-the-line HOB filter, this one also features multi-stage filtration.
The first stage is mechanical filtration, where Rite-size Penguin Cartridge filters out all the debris, including dirt and small stones, to give the water a clear appearance. It also features a propriety ribbed back that ensures the maximum amount of water comes into contact with its premium activated carbon chemical filter
This top-grade carbon filter treats the aquarium water for unwanted odors and the chemicals that are causing discoloration. The biological filtration in Marineland Penguin Power Filter is carried out by a unique patented Bio-Wheel filter. Using a wheel-like configuration increases the surface area of the filter. As a result, more water comes into contact and filters out for its nitrate and ammonia content.
This Bio-Wheel filter is not just efficient with its greater surface area. Its filtration mechanism also keeps the healthy bacteria in the water unharmed. If you want to dampen the motor’s noise and want easy access to filter cartridges, the use of its two-piece vented cover will come in handy.
- State-of-the-art Bio-Wheel filter for effective wet/dry biological filtration
- Comes with an adjustable mid-level intake— improved water circulation
- Easy to replace cartridges
- A reasonably-priced HOB filter
- A bit too noisy
- Needs frequent filter replacement
- Construction of Bio-Wheel could be sturdier
- Terms of warranty are vague
HOB Filter A Buying Guide
If you want to explore options other than the four HOB filters for 20 gallon tanks we have discussed here, take the following features/factors into consideration.
Flow rate is what determines the size and capacity of a HOB filter. A buyer can also guess the filtration and oxygenation capability of a filter by its flow rate. However, it doesn’t mean you need to always go for a filter with the highest flow rate. In some cases, a high flow rate for a 20 gallon fish tank is not recommended because it creates more noise and also may create a current too powerful for your fish.
Also, scientific studies have proved that different fish species have different flow requirements. If you don’t want to get confused with flow rate specs, just make a simple rule for that: a filter should be able to go through all the water in the tank for at least 4-5 times in an hour. This means a 200 GPH filter will be good enough for a 20 gallon fish tank.
The above filtration equation will help you in comparing a filter with your tank size. A 200 GPH is good for a 20 gallon tank. Similarly, 150-200 GPH filters will be suitable for 30-40 gallon aquariums. However, you can go for higher flow rates for your tank if they are available at the same price points.
Filtration media is another important factor to consider while buying a HOB filter. Keep in mind that having a host of different media doesn’t make a filter good with its filtration. The filtration primarily depends on the nature/material of the media. Usually, the main filtration medium used in HOB filters is a simple sponge. However, you can now get well-thought-out filtration chambers that also feature activated carbon coating on a sponge, biofilters, and ceramic rings.
These are some good filtration media and ensure holistic mechanical, chemical, and biological filtration.
It is better to pick from brands that have been around for years and have made several fishkeeping accessories, including HOB filters. AquaClear, Aqueon, Marineland, Fluval, and Marina are some of the trustworthy names of the industry.
The price is a subjective matter for buyers. However, it is still better to know what are the usual price points set for HOB filters for 20 gallon tanks. For instance, you can easily get a top-quality HOB filter in the price range of $20-50.
Learn A Few Good Tips For Hang On Back Filters
What Size Filter Do You Need For A 20 Gallon Tank?
Any filter that can deliver the flow rate of at least 200 GPH will be good enough for a 20 gallon tank. You can also opt for filters with higher flower rates if the fish in the tank don’t get frantic in higher currents.
Do I Need A Filter For My 20 Gallon Fish Tank?
Yes, you need a filter for your 20 gallon fish tank to oxygenate its water for keeping fish active. A good multi-stage filter also takes care of the mechanical debris as well as chemical and biological impurities like excessive algae buildup, ammonia, and nitrate to make sure the aquarium environment remains healthy for the aquatic life present inside.
That said if you are an experienced fish keeper and understand how live plants and an appropriately stocked tank can function as one system you can get away without a filter.
But like I said, you need to be experienced to pull this off.
Can I Put A 30 Gallon Filter In A 20 Gallon Tank?
Yes, you can put a filter rated for a 30 gallon tank in a 20 gallon tank. In fact, many times, the same filter is rated for both 20 and 30 gallon tanks. However, if you are keeping fish such as gouramis or shoaling fish that are not used to high water currents, it is better to stick to the prescribed rating.
A HOB filter helps can make keeping your water clean and healthy. A top-of-the-line filter takes care of all mechanical, biological, and chemical impurities of the tank and keeps beneficial bacteria in place. This well-thought-out filtration allows your fish to live through a long happy life. HOB filters are also considered a good choice for aquariums because they oxygenate the water without taking up too much space in your aquarium
Among the four HOB filters we have reviewed, we think AquaClear is the best HOB filter for your 20 gallon tank. It features 3-stage filtration that is topped with AquaClears patented mechanical sponge. Its flow rate is great and if you upsize to a 30 gallon tank you can still use the same filter if it’s lightly stocked with lots of plants.
We also like this HOB filter because of its hassle-free setup, it’s almost plug-and-play.
Learn More About HOB Filters:
- HOB Filter for a 10 gallon tank
- HOB Filter for a 20 gallon tank
- HOB Filter for a 55 gallon tank
- HOB Filter for a Planted tank
- Overall Best HOB Fitler Buyers guide