Aquarists are usually interested in the newest or most technologically advanced way of accomplishing a task like filtration. A noted exception is with our sponge filters, which haven’t changed much in the last 30 years. The best sponge filters are simple devices, but are useful enough that every fish keeper should keep a kit on hand!
Quick Comparisons Of The 5 Best Sponge Filters
|Aquatop Sponge Filter Kit||View Product|
|Fluval Edge Pre-Filter Sponge Tip||View Product|
|AquaPapa Corner Internal Filter||View Product|
|Huijukon Double Sponge Filter Kit||View Product|
|Lustar Hydro Sponge Filter Kit||View Product|
What Is A Sponge Filter?
A sponge filter is exactly what it sounds like; a filter that uses a fine or coarse sponge to mechanically capture particles of food and solid fish waste floating in your aquarium water. Unlike other styles of filtration such as HOBs and canister filters, sponge filters usually don’t include filter media or chemically clean the water in a tank.
Where things get a bit confusing for novice fish keepers is in the terminology. Other types of filters often include stages for water-polishing sponges or can be modified with a sponge filter tip, and yet they are not sponge filters. Let’s break down the details so you can see what sets these useful filters apart from the others!
What Comes With A Sponge Filter Kit?
While there are many styles and designs, all the sponge filters I’ve seen and used have the same basic set-up. Some of the newer types include expanded capacity for holding filtering media (more on this below), but this isn’t a standard feature. When you buy a full sponge filter system you can expect the kit to include:
- Sponge Tip– Either a coarse or fine spongy cover for the filter intake.
- Intake Tube– Plastic tube with holes, which the sponge tip fits over.
- Central Tube/Outflow– Either part of the intake tube or connected to the intake, the central tube may also be the outflow where water returns to your tank or may connect to a separate, adjustable outflow.
How Sponge Filter’s Work
Sponge filters sit inside your tank and either attach to the side or are weighted to sit on the bottom. Water is pulled through the sponge tip, where debris is collected, passes through the intake tube into the central tube and out the outflow back into your tank.
Sponge filters provide simple mechanical filtration to aquariums. While healthy aquatic bacteria may also become established in your sponge filter, they usually don’t provide that much biological filtration unless they have a special stage designed to hold bio-media long-term. Most of these filters are 1-stage despite their advertising.
How Are Sponge Filters Powered?
You’ll notice something is missing from the list of parts; it doesn’t include any power source. You’ll have to choose and purchase your power supply separately from the kit, either by getting an air pump for a sponge filter or investing in an aquarium powerhead. The lack of moving parts is the main reason these filters are so inexpensive.
Using Sponge Tips On Other Types Of Filters
You can often modify a HOB or canister filter by replacing the plastic intake screen with a finer sponge tip. This can make your filter safe to use with very small or delicate fish and shrimp that could be sucked through the regular screen. It’s often better to go with a coarser sponge so you don’t reduce your flow rates, though.
Maintaining Sponge Filters
A bonus feature of sponge filters are their extremely easy maintenance requirements. This is definitely the most hands-off filtration system when it comes to routine cleaning. You’ll usually just have to remove the sponge tip once a week or a couple of times a month (depending on the debris in your tank) and rinse it off.
Squeezing the sponge tip under running water until it’s clean only takes a few minutes, and then you can pop it back on the intake and go about your day. The sponges usually last for about 6 months before they need replacing, too. You may have to clean the intake, central and outflow tubes a few times a year, but that’s it!
Benefits Of Using Sponge Filters In Aquariums
There are many reasons why experienced aquarists keep sponge filter kits on hand even if they don’t use them all the time or as their primary mode of filtration.
- Sponge filter kits are very inexpensive and even premium systems rarely cost more than $20 initially.
- Replacement sponges are cheap, and they only need to be swapped out every 6 months, so overall operating costs are very low.
- They are very flexible and can be used in both freshwater and marine tanks and in tanks of any size.
- They are an excellent way of oxygenating your aquarium water.
- They don’t create a lot of water current, so, are ideal for low-flow fish like shrimp, Bettas and goldfish.
- Sponge filters are low-maintenance and only take a few minutes a month to clean.
- Since they (usually) don’t contain filter media, they are ideal to use in hospital tanks or when medicating your aquarium.
- Sponge filter tips also prevent tiny fish, fry, shrimp or snails from being injured by your other filtration system.
Disadvantages Of Sponge Filters
Despite their many advantages, these filters also have some serious drawbacks. While I advocate keeping a kit in hand for emergencies, there aren’t many situations where I’d use a sponge system as my primary filter, and here’s the reasons why:
- Sponge filters only provide 1-stage mechanical filtration and can’t neutralize toxins or remove odors from your aquarium water.
- The sponge tip alone won’t actually contribute much biological filtration to your tank since it is rinsed clean weekly to prevent clogging.
- Additional media compartments may provide more room for good bacteria to flourish long-term in premium sponge filters, but still provide less than other types of filters (or your substrate, for that matter).
- Tanks with sponge filters require at least weekly water changes to remove toxins from the water unless you’re using another chemically-cleaning system as your primary filter.
- Sponge tips can only filter out some debris and can quickly become clogged in a dirty tank.
- They can’t really polish the water like a HOB or canister system, and the flow rate drops substantially as the filter picks up debris.
- Depending on how fine or coarse the material is you may need to rinse the sponge tip clean more than once a week to keep the water flowing through the filter.
- While the sponge filter itself is inexpensive, you’ll also have to buy an air pump or powerhead to opera the filter.
|Inexpensive to set-up and maintain||Requires additional power source to operate|
|Can be used in freshwater, brackish and marine tanks||Only provides 1-stage of filtration (mechanical) so of limited use in most types of tanks|
|Ideal for hospital tanks and for filtering a medicated community tank since they don’t use chemical filter media||Effectiveness depends on the texture of the sponge, pore-size and how much debris is in the tank|
|Ideal for raising fry, snails, shrimp and other small, delicate aquatic species that could be sucked into a traditional screened intake|
Choosing The Ideal Sponge Filter For Your Tank
Let’s put everything together and talk about how to pick the ideal sponge filter for your tank! Unlike the more complicated filter designs, there really isn’t much to consider when buying a sponge filter. Nearly every type will do a decent job of removing debris from your water. Here’s what to look for in the best, however.
Aquarium And Filter Size
One big difference between sponge filters vs HOB and canister systems is that you don’t need to worry much about matching the size of your filter to the capacity of your tank. While these filters often come with recommended tank sizes listed, you can use any sponge filter in any sized tank as long as it fits inside.
You may pick up a sponge filter for a 10-gallon tank, but you won’t be limited to that size. I’ve used the same sponge filter in set-ups from 2.5 all the way up to a 75-gallon tank! Using a larger sponge tip in a bigger tank will reduce the frequency of cleaning, but the size doesn’t affect your flow rates; that’s controlled by the power source.
Replacement Parts And Price
Most sponge filter kits range from around $8 to $20, so even a premium filter won’t cost you very much. I wouldn’t worry about the price of the initial kit and instead, look into the cost of replacement parts and sponges. You’ll want to replace the sponge at least twice a year, so be sure you can easily source their replacements!
Despite the manufacturer’s advertisement and hype, there aren’t many special features available for sponge filter kits. You may be able to adjust the direction of the outflow current or raise or lower the position of the sponge tip for optimal debris collection. Weighted bases and suction cups can help hold the filters in place, too.
The advanced feature that can be worth looking for is a container or stage to hold extra filter media, if you’re using your filter year-round.
- You won’t need this for hospital tanks, but it can be useful for breeding fish, raising fry and general community tanks.
- The containers are usually designed to hold ceramic rings or other biological filtering media, but some may also allow chemical media like carbon to be used.
A Note On GPH Ratings And Sponge Filters
Another important difference between buying sponge filters and the other types is that these filters do not come with a flow rating in gallons per hour (GPH). That’s because the flow rate completely depends on the performance of your air pump or powerhead, and not the design of the sponge filter itself.
Sponge filters also do not have a consistent flow rate, because the rate drops as the sponge tip picks up debris and increases when it’s cleaned. So GPH isn’t a helpful spec to use to compare these filters to each other or other systems.
- Finer sponge tips often clog faster and slow the rate much more than coarser tips regardless of the overall design of the filter.
- This is why the coarser style is best when using a sponge tip with a HOB/canister filter, as you could burn out the motor using a finer product if it clogs and you don’t immediately catch it.
Sponge Filters and Filter Tips: Best Product Reviews
Since they are not a big-ticket item, you’ll find a large variety of sponge filters on the market, and many look nearly identical to each other. I wouldn’t worry too much about specific brands for these filters, and instead, pick the one that has the features you need, will work with your power supply and has easily available replacement parts.
1. Aquatop Classic Aqua Flow Sponge Filter Kit
- Tank Capacity: Up to 60 Gallons
- Dimensions: 5.5 x 5.5 x 8.5 inches
- Power: Air Pump or Powerhead
This straightforward system from Aquatop is a Classic for a reason: these high-quality filters have been around for years with very few design changes! The weighted base holds the fine sponge tip in place over the intake and the central tube doubles as the outflow. You can place this one in any part of your tank, too.
This versatile sponge filter kit can be used with an air pump or powerhead, and can help increase the oxygenation of your water as it bubbles through the outflow. I really like the quality of the sponge tip, and it’s the ideal size for trapping the majority of the debris. It’s getting harder to find replacement parts for this system, however.
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2. Fluval Edge Pre-Filter Sponge Tip
- Tank Capacity: N/A
- Dimensions: 4.5 x 1.7 x 1.7 inches
- Power: N/A
If you’d just like to add a pre-filter tip to your HOB or canister system, I highly recommend the Fluval Edge Sponge Tip. This coarse sponge tip won’t clog as easily as the finer sponge filters, so it won’t slow down your filter’s GPH rate or reduce the flow. It’s a great way to keep smaller fish and shrimp from being sucked into a filter.
It’s designed specifically for the Fluval Edge filtration system, but the tip will fit on any intake tube that’s an inch in diameter. I’ve used it with a Marineland HOB with no problems, and it’s easy to rinse clean and cheap to replace!
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3. AquaPapa Corner Internal Filter
- Tank Capacity: 5 to 10 Gallons
- Dimensions: 5 x 3.4 x 3.4 inches
- Power: Air Pump
If you need a sponge filter for nano tanks, then this interesting hybrid system could be the one for you. It’s an ideal sponge system for a 10-gallon or smaller set-up. It isn’t actually a sponge filter, but a compact internal filter with two water-polishing sponges and a small compartment for holding biological filter media.
This compact filter sits discreetly in a corner of your tank. Water is pulled by an air pump through a plastic screen and into the first compartment with the sponges. This wouldn’t be an ideal system for raising fry or shrimp, which could be pulled through the plastic screen, but is perfect for Bettas and other nano fish.
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4. Huijukon Double Sponge Filter Kit
- Tank Capacity: 10 to 60 Gallons
- Dimensions: 5.9 x 2.4 x 11.1 inches
- Power: Air Pump
If you want a flexible sponge filter that can be used in many different ways, then I highly recommend this Double Sponge Filter Kit from Huijukon. With two high-quality sponge tips, this filter can cycle twice as much water at a time and is less likely to clog than any other system on the list. It’s also one of the easiest to maintain.
This filter comes with optional canisters you can attach to the sponge intake tubes. You can fill these with your choice of chemical or biological media for additional filtration power! This is a great option for fry and shrimp tanks, hospital set-ups and as a secondary filter for any freshwater or marine tank. This would be my pick for a sponge filter!
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5. Lustar Hydro Sponge Filter Kit
- Tank Capacity: 10 to 40 Gallons
- Dimensions: 6.2 x 4.4 x 4.1 inches
- Power: Air Pump or Powerhead
The Lustar Hydro Sponge Kit is another option if you want a classically styled and basic filter that can operate with either an air pump or powerhead. This is their mid-range model, with a very fine and easily clogged sponge tip. You’ll have to upgrade to their Pro series if you want the coarser reticulated sponge tip.
This is an ideal sponge filter for a tank of fry or a breeding tank with a low bioload. The fine material will keep any eggs or babies safe from the tug of the filter. But weekly cleaning is needed to keep the sponge from getting clogged with debris. The frequency of maintenance will reduce its ability to provide biological filtration.
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I hope you’ve enjoyed this short guide to sponge filters, and I’d love to hear your feedback in the comments or on social media! Sponge filters are very useful no matter what size or type of tank you’re maintaining, and these flexible systems are ideal for raising delicate small fish, fry and shrimp and for hospital tanks.
If you’re still not sure which is the ideal sponge filter for your home, don’t stress over it. These are inexpensive enough that you can easily upgrade if you don’t care for your first pick.
- I’d go with the versatile Huijukon Double Sponge myself, and I’ve used the Fluval Sponge tip on my powered HOB and canister filter intakes for years.
- The Aquatop Classic is a great basic sponge filter perfect for bigger tanks up to 60-gallons in size, or opt for the Lustar if you prefer a finer sponge tip.