Sponge filters have been around for decades; in fact, they were likely some of the first filters ever used by aquarists. While many truly are a sponge attached to an airline hose, this basic design has been improved upon by inventive manufacturers time and time again over the years. Nowadays we have options that greatly expand what sponge filters are capable of doing. So let’s talk about the best sponge filters on the market today! As well as what a sponge filter is and when it’s right for an aquarist’s needs.
The Best Sponge Filters of 2021
It was tough choosing between the myriad options available in today’s saturated aquarium world! But these are my top recommendations that best balance quality, affordability, reliability, and function!
Top five Sponge Filters
- Lefunpets Sponge Filter
- AQUANEAT Aquarium Bio Sponge Filter Corner Filter
- AQUANEAT Aquarium Air Driven Bio Corner Filter Sponge
- hygger Aquarium Double Sponge Filter
- UPETTOOLS Aquarium Biochemical Sponge Filter
- Huijukon Double Bio Sponge Filter Foam Filter
When Should I Use a Sponge Filter?
Sponge filters are sometimes forgotten when people decide to buy a new aquarium. Power and canister filters typically get more attention. But sponge filters provide most of the same qualities for much less energy, expense, or maintenance!
Sponge filters are excellent at providing both mechanical and biological filtration, two of the three main cornerstones of keeping aquarium water healthy! The micropores trap leftover food, feces, and other suspended debris, keeping it from irritating fish gills or getting trapped in the gravel and rotting.
The sponge also provides a home for beneficial bacteria that break down this debris and feed on dissolved ammonia, nitrite, and other waste products. They work to convert them into nitrate, a relatively harmless chemical that is then removed each time you perform a water change. Sponge filters are a great water treatment option for smaller aquariums and for beginners who are intimidated by the complexity of a larger unit!
My Top Choices for the Best Sponge Filter
Sometimes an affordable, straightforward sponge filter is ideal for one’s needs. Where others add extra biological filtration capacity the Lefunpets prefers to stick to classic designs. Lefunpets has models ranging from one rated for 5-10 gallon aquariums to a massive unit suitable for up to 80-gallon aquariums. This particular filter uses a unique six hatched design and a non-biodegradable synthetic material that will last years being submerged and colonized by bacteria. The pore size of the sponge is also especially small. This tradeoff makes it faster to clog if your water has a lot of suspended debris but is more efficient at processing ammonia and other dissolved chemicals.
To aid in maintenance, the tubing and plastic attachments can all be detached and reassembled in mere minutes. This way, you don’t have to dig around for a user manual every few weeks when you need to clean the unit. All that’s required for operation is an air pump, airline, and check valve (to prevent water from flowing upwards in case of power outages)!
- Straightforward design that takes little to no study before operating
- Sponge will last years with proper maintenance
- Easily disassembled for quick cleaning
- Extra-fine sponge porosity for added bacterial surface area
- Adds no chemical or extra biological filtration capacity as more advanced units provide
- Small pore sponges are faster to clog
Classic sponge filters like the Lefunpets and AQUANEAT Bio Sponge may seem identical at first glance. But there are some differences that are important to many aquarists that you should consider! Compared to the Lefunpets design, one difference is the larger pores of the AQUANEAT sponge. This tradeoff works in reverse; while there is less surface area on and within the sponge filter for beneficial bacteria to make a home, it’s better at screening your water for pieces of floating debris.
Another is the corner molded shape, which allows you to more efficiently make use of the area a fish tank allows. The AQUANEATS design molds better into the aquascape versus the rounded or blocky shapes of other sponge filters! Its only real drawback is that it doesn’t break down as completely as the Lefunpets, which can be taken apart entirely for deep cleaning.
- Corner molded design that makes good use of bottom real estate
- Larger pore size, which doesn’t clog as quickly and provides better water flow
- Very quick to set up and maintain over time
- Large pore sponges aren’t as efficient at removing chemical waste like ammonia and nitrite.
As much as I love the AQUANEAT Bio Sponge, they have an even more interesting Air Driven Bio Corner Filter to explore! This unit builds on the foundation of a traditional sponge filter, which is essentially a sponge connected to a plastic spout and airline tubing. Now we see a plastic media compartment with not only a bio sponge but cotton floss and ceramic rings as well!
The first level is a triple layer of sponges that gradually increase in density as water penetrates the unit (it’s best to reverse the stacking order as shown in the photograph). Next, a layer of included pebbles acts as a counterweight for the slightly buoyant plastic and foam.
Finally, included ceramic rings provide extra high-density living space for beneficial bacteria to colonize. Remember that you never need to change these out, as you would chemical media. Also, you can modify the layers, removing either a layer of foam or the ceramic rings to make room for activated carbon, ammonia absorbing resin, or other specialty chemical media!
- Uses a triple-stacked foam filter design to prevent clogs from affecting each layer
- Includes pebbles to weigh the unit down along the bottom
- Ceramic bio rings are one of the best solutions for encouraging the growth of beneficial bacteria
- Can be modified to hold chemical media
- Largest unit rated only for up to 40 gallon aquariums
Hygger is becoming a major brand in the world of online aquarium products; they are known not only for quality sponge filters but affordable LED lighting as well! The hygger design is one of the best balanced in terms of catering to the needs of aquarists while sticking to the simplistic style that sponge filters do so well.
We get a twin sponge design in all of their units, which are rated for aquariums of 10 to 55 gallons in volume. Hygger went with a fine-pored bio sponge here, which normally sacrifices flow capacity for increased biological filtration ability. However, by using twin sponges with multiple grooves cut into them, hygger increased their total surface area, effectively negating the flow penalty!
And once water flows past the bio sponges a secondary chamber full of spherical ceramic media balls provides another boost of biological filtration action, sucking up any leftover ammonia or nitrites missed by the initial screening. Hygger also allowed for the air-water outlet tube to telescope up and down in order to best fit a particular aquascape. Lastly, each unit includes two spare sponges as the sponge’s decay over time.
- Twin sponge design with grooves cut to increase their surface area enough to make up for the small pores
- Tiny pores and secondary ceramic media provide plenty of space for beneficial bacteria to colonize
- Telescoping air water outlet tube
- Each unit includes two extra sponges
- Sponges are estimated to last 3 to 6 months and should be replaced thereafter, according to hygger
One aspect of the UPETTOOLS Biochemical sponge filter that catches my attention is the included rear suction cups lining the air-water outlet tube. These provide a way of securing the sponge filter to the glass and preventing it from floating away or being easily disturbed by larger fish. UPPETOOLS also put thought into how flow leaves the unit and made the head of the outlet tube adjustable a full 360°.
The neon green and black sponges are available in both single and double sponge models. I appreciate that UPETTOOLS gives us this choice because both offer noteworthy benefits. A green sponge is easier to gauge for maintenance purposes. It will steadily turn dark green and then brown, signaling that you need to clean the unit. Green also makes it easier to observe fish fry, baby shrimp, and other small animals that might be grazing on the sponge. A black sponge is less visible, which makes it easier to hide in the aquascape but harder to gauge when service is needed.
- Your choice of bright green or matte black sponges for either ease of maintenance or viewing purposes
- UPETTOOLS offers both single and double sponge for a variety of tank sizes
- All units also have a secondary chamber for ceramic biomedia
- Fully rotating head and suction cups affixed to the air water outlet tube
- White ceramic media and neon green sponges stand out even from the back of an aquarium
If you’re undecided about the simplicity of a sponge filter without ceramic media but want the extra flow potential of a double sponge, Huijukon’s design is just right for you. This unit does away with a secondary bioreactor full of ceramic balls in favor of tall twin bio sponges. Each sponge has nine grooves cut into the surface, which not only improves the ability of water to circulate around them but increases their total surface area as well.
Normally, fine-pored sponged like the Huijukon are quick to clog with heavy waste but the improved flow and greater surface area of the unit keeps this from happening. And you also reap the benefits of the smaller micropores, which provide extra interior surface area for beneficial bacteria to colonize!
The Huijukon also has suction cups attached to the air-water outlet tube so it can be fixed into place despite its natural buoyancy and the attention of curious fish. The tube can also be adjusted in height from 9.4 to 13.8 inches and the outlet spigot can be directed to create ideal circulation for any aquarium!
- Sticks to the original sponge filter concept for ease of maintenance
- Combines twin sponge filtration design with channeled sponges for better water flow and less clogging
- Air water outlet tube has suction cups for attachment to glass and can be adjusted in both height and water flow
- Unit includes no option for adding chemical or extra biological media
Which Sponge Filter is Right for You?
As you’ve come to appreciate, the sponge filters available here are all excellent at what they do: providing excellent water quality for aquarium fish while being easy to both setup and maintain. So which of these units meets the needs of most aquarists while doing the best overall job? I find that the hygger Aquarium Double Sponge Filter will be right for most hobbyists! The twin, well-grooved sponge concept covers for the weaknesses of the micropore design while providing loads of biological filtration action, which is the most important of the three modes. It is also the right color, price, and size for the vast majority of aquarists!
Pros and Cons of Sponge Filters
Sponge filters have many benefits over the larger and pricier power filters on the markets. But they also aren’t right for every setup. So let’s take a look at the pros and cons of using a sponge filter, compared to a canister or hang on the back power filter!
What are Sponge Filters Great At?
Simplicity and Speed
If you’re looking for an efficient filter that’s quick to set up and maintain for a child or beginning aquarist, there’s no matching a sponge filter. They don’t have complex magnetic impellers to calibrate during cleaning, don’t have huge media trays to refill, and you’ll rarely if ever, need to refer to the user manual. A sponge filter simply attaches directly to the outflow of your air pump, providing oxygenation, current, and filtration, all at once. Maintenance can be performed in just a few minutes as well!
This simplicity means that the parts for a sponge filter are easily replaced if damaged because there are no moving parts whatsoever. At worst, you may end up with a cracked air tube or worn-out sponge over time. These materials are readily found at your local fish store or can be ordered from the manufacturer with ease. And replacing these parts also takes just a few minutes.
Cleaning a sponge filter is also as easy as can be! Maintenance depends mostly on the variety of media it uses. The simplest designs use just a foam sponge to trap debris and house bacteria. The sponge should be detached from the air tubing once the flow starts to slow due to clogging. You should then gently rinse the sponge in a bucket of water from your tank. Don’t rinse the sponge under the faucet because tap water has chlorine and chloramine that will kill your beneficial bacteria.
Once the surface of the sponge is free of debris, a few gentle squeezes are all that is required. The thick, slimy brown mulm that forms within the sponge looks and feels nasty. But you’re actually looking at the bacterial colonies that keep your fish healthy. So we don’t want to sterilize our sponge filter; we want some of that gunk to remain behind. Remove just enough mulm that water starts to flow freely through the sponge once more! Here is an in-depth breakdown of the process to study:
Smaller aquariums of 10 gallons and under often have such a small water volume that a power filter will turn over the entire tank in just minutes. Normally we want as much water turnover as possible. But in a small tank, it’s easy for little fish and shrimp to get blown about by the force of a powerful mechanical pump.
Sponge filters are better for nano tanks because they don’t create huge amounts of current. They also have loads of surface area, providing not only ample mechanical but biological filtration capacity as well. In fact, many sponge filters actually have more surface area relative to aquarium volume than a power filter for a larger tank provides!
Raising Fish and Shrimp Fry
Do you have a pregnant guppy, berried dwarf shrimp, or a breeding pair of cichlids? If so, then sponge filters are the best possible filters to use in a fry rearing tank! Power and canister filters have an intake pressure that’s much too powerful for baby fish to resist. They will eventually get sucked up and killed by these types of filters. But a sponge filter uses an air pump as its source of flow, providing a constant, gentle current that young fish can easily resist.
As sponge filters collect debris they also become colonized by bacteria, algae, and other microscopic life, which fish fry will then feed on.
Sponge Filters Will Survive Power Outages
Occasionally, a winter storm or falling tree can result in a sudden power outage. Now, there’s no light, heat, or aeration going to your aquarium. Hopefully, the outage is very temporary. But this is an instance where a sponge filter has a dramatic advantage over a power or canister filter.
As you know, all filters hold billions of beneficial bacteria that feed on nitrogenous waste. They convert dangerously toxic ammonia over time into relatively harmless nitrate. However, they are aerobic (oxygen-loving) organisms, just like fish. During a power outage, flow between your tank and filter stops because the pump is no longer working. If the outage lasts for too long, the bacteria in the filtration chamber will use up their oxygen and start dying. This can lead to the tank partially or fully crashing because it’s no longer considered cycled. However, a sponge filter remains soaking in the aquarium, where there is more than enough oxygen to support them for the entirety of the outage!
When Should I Use Another Filter?As versatile as sponge filters are, there are some cases where you and your fish will be happier with a canister or power filter.
Aquariums with Medium to Large Sized Fish
Sponge filters are great solo filters for smaller fish setups because they have a smaller bioload. By bioload, I mean the waste that they create (ammonia, feces, nitrites, etc) that build up over time. A sponge filter can process a small amount of load in a smaller tank with ease.
But for community tanks with medium-sized fish (3+ inches) or larger, you shouldn’t rely solely on a sponge filter. A pair of breeding cichlids will be okay in an appropriately sized tank. But I would not run a sponge filter as the main filter on a tank larger than 55 gallons unless I’m ready to perform small (10-20%) weekly or even biweekly water changes. Large fish simply create too much waste for a sponge filter to keep up with and the current they generate isn’t strong enough to circulate throughout the entire tank.
Aquascapes that use more Substrate Area
One disadvantage to sponge filter designs is that they sit directly on the bottom of your tank. A hang on the back power filter or canister filter has a hose that collects water and channels it outside, where the bulk of the unit resides.
If you have a heavily planted, rocky, or wood-filled aquascape, a sponge filter can complicate things because they occupy bottom real estate. Loads of decorations can also hamper flow to your sponge filter, making it harder for the unit to properly process fish waste. For heavily aquascaped tanks, an exterior filter will do a much better job of providing clean water.
Situations Where I need Specialized Media
Sometimes you’ll need to use specialized chemical media for solving a particular water quality issue. If a recent overfeeding is causing a constant issue with ammonia, you can’t add ammonia-absorbing resin to most sponge filters. Some have separate media chambers but even these are much smaller than those used by power and canister filters.
Some sponge filters also have room for lava rock and other additional biomedia. But if you want to add, say, micropore ceramic media for denitrifying bacteria, a sponge filter won’t do the job here. Likewise for large amounts of resin that absorb phosphates (to control algae) and other situations where a targeted solution is needed.
Sponge filters aren’t as capable as a power or canister filter. But sometimes all of that extra capacity is simply wasted space and energy. For aquariums with smaller or fewer fish and situations where a gentle current is required, a sponge filter does the job at a fraction of the cost. Both in terms of price as well as time spent setting up and maintaining the unit, leaving you with more energy to simply enjoy your fish!