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I remember as a kid thinking fish just liked water and breathed it and everything was cool as long as they had enough of it. I remember getting in trouble for just dumping tap water into the aquarium, too, when I thought it got too low – followed by a lecture from my dad on why that was a terrible idea.

Since then, I’ve been keenly aware of the need for proper filtration of water for fish tanks with live plants and gravel beds to clean up that detritus and build-up of unhealthy gunk in there. Not only does it cleanse the chemicals from tap water before it goes into the tank, but filters for the fish tank themselves to clear out gunk left behind those little finned guys, as well as providing a home for beneficial bacteria.

But there are many kinds of aquarium filters out there and deciding which one is right for your needs can be tricky. So, we’re offering up some helpful info and reviews on the best undergravel filter that works best for you.

Best Under Gravel Filter Quick-Find Table

Image Product
  • Durable and affordable
  • Easy to install and adjustable
  • Great for basic needs, no frills required
  • Durable and affordable
  • Easy to install and adjustable
  • Great for basic needs, no frills required
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  • Perfect for low-maintenance needs
  • Ideal for newbie hobbyists
  • Offers mechanical and biological filtration
  • Perfect for low-maintenance needs
  • Ideal for newbie hobbyists
  • Offers mechanical and biological filtration
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  • Circular tubes for easy configuration
  • Connects with other system pieces for the ideal setup
  • High-quality manufacture
  • Circular tubes for easy configuration
  • Connects with other system pieces for the ideal setup
  • High-quality manufacture
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  • Good for many different fish tank sizes, including larger tanks
  • Double the riser tubes of other brands
  • Made of crack resistant plastic
  • Good for many different fish tank sizes, including larger tanks
  • Double the riser tubes of other brands
  • Made of crack resistant plastic
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  • Perfect for small fish tanks
  • Easy for anyone to use, including new hobbyists
  • Budget-friendly
  • Perfect for small fish tanks
  • Easy for anyone to use, including new hobbyists
  • Budget-friendly
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Reviews of the Best Undergravel Filters for Aquariums

Without further ado, let’s jump into our reviews. We’ve broken them down by overall best choice, but also by type, so if you’re looking for a specific type of filter, we’ll have you covered below.

The Penn-Plax Premium Under Gravel Filter is a powerful option, suited for use in a number of different tank sizes, most commonly those between 20 and 30 or 40 and 50-gallon aquariums. They’re durable, lightweight, easy to install, and adjustable, plus they actually do the job, making them a great option for folks overall looking for a basic, quality under-gravel filter.

  • Capacity: 20-30 or 40-50 gallons
  • Type of filtration: Chemical and mechanical filtration, with carbon filter cartridges
  • Adjustable: Yes
  • Type: Freshwater or saltwater tanks

What We Loved

First off, we love how absolutely easy this filter is to install. It’s really simple and basic, and anybody can do it, even if this is your first aquarium.

This great filter is perfect for use in either freshwater aquariums or marine tanks and includes chemical filtration to meet your needs. It comes with replaceable activated carbon cartridges, too.

The filter includes an air stone, as well, and everything easily fits together, thanks to the simple, easy design.

The lift tubes have adjustable height function, as well, meaning this really does suit just about any tank in which under gravel filtration is ideal.

What We Didn’t Love

The only potential issue with this is for those with some aggressive fish. The filter plate connectors aren’t as sturdy as needed for fish who tend to bump around or aggressively chase others. It also does not include an air pump or airline tubing – you’ll need to buy those separately.

Our Verdict

For a no-frills, easy option that’s affordable and works well, this Penn-Plax filter is a fantastic solution. The tubes adjust for finding the right height, chemical filtration, and carbon filter cartridges come included, and set up is easy. It’s a winner all around.

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BEST FOR SMALL AQUARIUMS

2. Imagitarium Undergravel Filter

The Imagitarium Undergravel Filter is another fantastic option for folks looking for filtration for smaller aquariums (10 gallons). This low-maintenance option is perfect for newbies aquarists or old hats alike.

  • Capacity: 10 gallons
  • Type of filtration: Mechanical and biological
  • Adjustable: No
  • Type: freshwater or marine

What We Loved

The filter includes two carbon filter cartridges, which is a great way to start things off.

This filter is also ultra-low maintenance, which is a hugely beneficial quality for anyone learning the hobby and for kids who’d like to learn but aren’t quite there yet on responsibility levels.

The filter also comes with air stones, which is great, especially since the filter is super budget-friendly.

What We Didn’t Love

Though the filter does offer biological filtration, it’s recommended that you also use additional filters with this to provide more surface space for that beneficial bacteria growth.

Also, you’ll need your own air pump for this one, along with airline tubing.

Our Verdict

Ultimately, this is a really great option for small aquarium owners who don’t want to mess with a lot of maintenance. You only need to clean the filter every 18 months or so, which is a huge bonus for newbies and kids who aren’t always so great with remembering such things. Just remember to buy airline tubing and an air pump to make this work.

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Another high-quality filter for your consideration is the Aquarium Equip brand Circular Bar Undergravel Filter. The filter is designed for mid-sized tanks of around 55-gallons and works great for your basic needs without a lot of maintenance.

  • Capacity: 55 gallons
  • Type of filtration: Mechanical and biological, connects to sponge filters
  • Adjustable: Yes
  • Type: Marine or freshwater tanks

What We Loved

We love how adaptable this filter is. It connects easily with its multiple joints and components to adjust to the right setup for your aquarium.

It’s extremely discreet, which is great for your aesthetics as well.

It’s a circular filter, meaning it improves water circulation as well, and provides plenty of space for beneficial bacteria to grow.

This filter also helps neutralize water temperature and provides double filtration for clear water for a long time. Plus, it can be connected to other filters and equipment easily for the perfect setup for your aquarium setting.

What We Didn’t Love

The only real downside on this is that it’s a little tricky to install. With the various pieces, it’s highly adaptable, but that means there are more things to connect and deal with as you connect.

Our Verdict

Overall, this is a fantastic circular filtration system for clean, clear water in your 55-gallon tanks. The filtration does the trick through mechanical and biological filtration (plus the ability to connect to other filters, as needed), while also improving water quality through circular movement. It’s a bit tricky to install, though, so if you’re looking for something super simple and fast, this may not be the best option for you.

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Lee’s Premium Undergravel Filters are a great option for folks with larger tanks (though they come in smaller sizes as well). The filter uses four riser tubes, is super durable, and honestly just works great.

  • Capacity: Largest size up to 135 gallons (this one for up to 65 gallons)
  • Type of filtration: Biological, mechanical
  • Adjustable: No
  • Type: Marine or freshwater

What We Loved

We love that this two-plate system has four tube ports.

We also appreciate the fact that this system comes with carbon cartridges, so extra purchases at the get-go.

Probably the most important feature (besides available sizes) is the durability and crack-resistant manufacture of the plates and tubing.

What We Didn’t Love

The only potential negative on this is that some folks complained of the filter tubes being a little small. Otherwise, it’s a great filter option.

Our Verdict

All in all, this is a great filtration system, especially for folks with larger tanks (this model for 65 gallons, others available for up to 135 gallons). It works well, it lasts a long time, and it provides plenty of space for that beneficial bacteria to thrive.

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The Aquarium Equip ISTA UGF is a great option for the budget-conscious. This particular low-key but effective filter doesn’t have any extra frills, sure, but it’s easy to set up and use, no matter who you are and no matter how experienced you are.

  • Capacity: This model for 5-gallon fish tanks
  • Type of filtration: Biological and mechanical
  • Adjustable: No
  • Type: Marine or freshwater

What We Loved

First off, for a budget-friendly option, this is a well-made filter that anyone can easily install and use in their small fish tanks.

It’s possible to connect it with multiple other equipment pieces, as well, for better circulation, such as an air pump, powerhead, HOB filters, etc.

Of course, we also love that this is so budget-friendly. It’s perfect for folks just starting out, learning to be fishkeepers or more experienced folks who want low fuss for their micro-tank or nano tanks.

What We Didn’t Love

The only potential issue we saw with this is UGF that you cannot use chemical filtration with it.

Our Verdict

If you’re looking for a super budget-friendly option, this undergravel filter is a perfect choice. It’s inexpensive, durable, works for saltwater or freshwater fish tanks, and comes highly recommended by folks who’ve used the same filter over and over again.

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What is an Undergravel Filter?

If you’re done any research at all or are already an established aquarist, you’ve heard of the many kinds of filters out there, from the HOB (hang-on-back) to the canister. One of the filter types that is definitely a bit more niche is the undergravel filter. In the old days, they were the go-to, but now with the many other types out there, you might have to study a little to get to know it and whether or not this type of filter system is the right one for you or not.

An undergravel filter, or UGF, is a plastic grate, coil, or plate that goes at the bottom of the tank, underneath your substrate. Pretty much it does as the title says – it’s a filter that resides under gravel.

The filter is a mechanical filter automatically by its nature, and most are also biological filters, due to the way they’re built. The mechanical aspect of the filtration system pulls water down through the gravel and over the filter component (plate, grate, etc.). This also becomes a biological filter because of presenting a large surface area for that beneficial bacteria to grow on.

The UGFs have two vertical tubes that have airstones inside them. These are powered by air pumps or powerheads at the top of each tube, drawing the water up through them, along with bubbles that are generated by the airstones.

This suction action pulls water down through the substrate into the filter plate, and thus, you’ve got your effective filtration system going.

Most UGFs are powered via an air pump and generally are recommended for tanks 55-gallons or smaller unless you want to and a powerhead or other filtration as well.

UGFs also tend to be on the less expensive side of filters, which makes them a great option for folks on a budget.

Benefits Of Undergravel Fish Tank Filters

Reliable And Easy To Use

If you are looking for a filter that is easy to use, then you should consider purchasing a UGF. This filter is a great choice for aquariums because of its reliability and simplicity. UGFs are valuable because there are no mechanical parts that move.

This filter type uses a powerhead or air pump to filter. Investing in a reliable UGF allows you to have peace of mind about your aquarium staying clean.

Quiet Running

UGF systems are known for being more silent than other pumps. The only noises they make come from the bubbling water as it works. The ambient noise is quiet enough that you can keep your aquarium in your bedroom or work area.

Minimal Maintenance Requirements

Undergravel filters have an advantage in that they do not have cartridges or sponge filters that need replacing or cleaning. The only maintenance you need to worry about is vacuuming your tank gravel during your weekly water change.

Superior Biological Filtration

Non-UGF filters only offer a few square inches that bacteria can grow on. UGF‘s can use the entire bottom of your aquarium. This combined with the weekly vacuuming of any solid wastes means your aquarium fish will have clean and clear water.

Aesthetics

Another advantage of using UGF filters is that they are hidden under the substrate. Other filters have external filers that stick out and look unnatural.

The only visible part of the UGF filter is two transparent columns that are filled with bubbles. These columns can easily be concealed with plants.

Inexpensive and Low Maintenance

Another advantage to this type of filter is how cheap it is. You only have to purchase the unit along with either a powerhead or pump.

The only reason to buy something else for this filter is if the pump itself breaks. There is no need to worry about getting any replacement filter media.

Suitable For Poor Swimmers

If your fish are weak swimmers then a standard filter may put out a water flow rate that is too strong for them. Bettas and goldfish cannot handle strong water currents. These fish do much better with the gentle bubbles produced by UGFs.

How To Choose An Undergravel Filter

Once you’ve decided that a UGF is the right fit for your aquarium, there a few things you’ll want to consider as you shop. These are the things we keep in mind before suggesting any and will come in handy for your selection process.

Aquarium Size

First off, the size of your aquarium is critical for choosing the right filter setup. They are sized a certain way, so they only work with certain size tanks.

Additional Components

Most UGFs easily connect into a fully integrated filtration and power system for your fish tank. They connect with air pumps, powerheads, other filters, etc. Some, however, do not. Be sure that the one you select works with the setup you already have or plan to install.

Filtration Type

A key component of any filtration system is the type of filtration you can do. And with an undergravel filter, you’re a little more limited than with some others. They’re not great for dirty species, like goldfish unless you have additional filtration installed, nor sometimes for setups where you require chemical filtration. Verify the one you’re interested in works with this type of filtration if you need it.

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