Sponge Filters: 17 Things You Should Know (For Beginners)

Sponge filters are amongst the most favored types of filters in the community of aquarists due to the benefits it provides for aquarium inhabitants and how efficient it is to use.

Although these may be good filters, it’s important to know which tanks are compatible with them.


Are Sponge Filters Good?

Yes, sponge filters are good because it’s affordable, it creates gentle currents, it’s simple to use, they’re quiet, they can be replaced easily, they’re easy to clean, they’re compatible with most tanks, and they can be used alongside HOB filters and canister filters.

The factors that make sponge filters good are quite a lot and the ones that we’ve previously mentioned are just a gist of what these filters offer. We’ll be going into detail about what makes sponge filters good.


Sponge filters are far from being costly because they don’t require a lot of additional components to function. When you purchase a sponge filter all you need is an air pump, plastic housing, and plastic tubing.

The average price of sponge filters would be $6-$13 on Amazon but you can go ahead and check your local pet store to see if the price would be cheaper compared to getting them online.

In the long run, sponge filters would still be affordable despite having regular sponge replacements once the sponge is close to breaking apart.

It Creates Gentle Currents

Another thing that makes sponge filters so nice is their ability to create gentle currents inside the tank.

There are certain species of fish that require gentle currents because fast and strong currents would tamper with the tank inhabitant’s oxygen and water temperature. Strong currents will also push fishes towards a filter, and would most likely suck them in; we all know what happens next and it’s not pretty.

Here are some species of fish that would love to live in a tank with gentle currents:

  • Betta fish
  • Fish fry
  • Brine Shrimp
  • Rasboras

These Are Simple Filters

Again, sponge filters don’t require any other fancy components to function, so right off the bat, these are simple filters. Sponge filters only need an external air pump and plastic tubing to function.

Despite only having three components, sponge filters can provide both mechanical and a bit of biological filtration. Initially, sponge filters solely use mechanical filtration, however, as time goes by, the filter will start to house beneficial bacteria. By this time, the sponge filter now has two filtrations; a mechanical and biological filter.

Although HOB and canister filters have an edge when it comes to providing a tank with fast water flow and chemical filtration, the sponge filter doesn’t fall short since it’s able to provide both mechanical and biological filtration, both of which are essential in maintaining the healthiness of an aquarium.

Quiet Filters

Sponge filters are relatively quiet but this would depend on what kind of air pump is being used. Luckily, air pumps nowadays have rubberized seals, and that greatly reduces any sort of noise.

Furthermore, sponge filters still provide enough surface agitation (despite not having strong surface agitation compared to other filters) that would sustain both fish and plant inhabitants inside a tank.

Can Be Paired With Other Types Of Filter

Are you using a HOB filter or a canister filter but you still want to add another filter system in your tank? If the answer is yes, do you still have the budget to afford another filter? Well, worry no more because sponge filters work great alongside other types of filters.

If you’re using a powerful filter system like a canister filter, then you can use a sponge filter as a pre-filter to block the suction of the canister filter. This would prevent small fish from getting sucked inside the filter.

Another thing, a pre-filter sponge can also act as a home for beneficial bacteria over time. Do take note that it has a smaller surface area so the beneficial bacteria won’t be a lot.

Compatibility With A Wide Array Of Tanks

Sponge filters are great because of their flexibility when it comes to tanks. These filters can be used for almost every kind of tank you can think of. Some examples would include:

  • Freshwater aquariums
  • Saltwater aquariums
  • Planted aquariums
  • Shrimp-only aquariums
  • Paludarium
  • & a whole lot more!

These Protect Small Fish

As previously mentioned, sponge filters can prevent the death of small fishes by acting as a pre-filter to block a powerful filter from sucking in fish. Also, the water movement that sponge filters provide is gentle, this would also prevent the death of other species of fish in tanks with strong currents.

Continuously Functions Even During Power Outages

Since sponge filters are directly immersed in tanks this would continue to house beneficial bacteria for a longer time compared to other filtration systems during a power outage.

The mechanical filtration will stop functioning during a power outage, and at the same time, there won’t be any water movement in the tank. This would be a big factor in causing the deaths of fishes, luckily, the biological filtration of a sponge filter will continue to keep tank inhabitants healthy for quite some time.

Cleaning Sponge Filters Are An Easy Task

Cleaning a sponge filter would be easy for both beginners and advanced fish keepers since they’ll only need aquarium water and their hands; that’s it.

These are the following steps in cleaning a sponge filter:

  1. First, grab the sponge filter and submerge it in aquarium water.
  2. Gently squeeze the sponge (one to two times) and brush off the debris you see on the surface. Remember not to brush off too much debris because some of these would contain the accumulated beneficial bacteria.
  3. After wringing out most of the water from the sponge, re-attach it to its plastic housing and you’re good to go.
  4. Repeat this process every few weeks and that should prevent any clogs from happening and prolong the lifespan of the sponge.

The steps listed above are only applied to single sponge filters. If your tank has multiple sponge filters, then the best way to clean these is by making a cleaning schedule for each sponge. Don’t clean all the sponges at the same time as this would increase the chances of getting high nitrate levels in your tank.

Do Sponge Filters Have Carbon?

No, sponge filters don’t have carbon in them. However, if you want to add carbon into your tank, you can put activated carbon in your filter. It’s best to use a sponge filter to act as your biological filter to grow beneficial bacteria.

Adding a carbon filter to your tank isn’t necessary. The only reason why some people add carbon to their tanks is to remove dissolved contaminants such as chlorine, phenols, and chloramine. Ultimately, carbon also prevents aquarium water from turning yellow.

Moreover, it’s important to take note that carbon isn’t able to remove the following elements inside your aquarium:

  • Heavy metals (e.g. lead and copper)
  • Ammonia/nitrate

If you want to lessen or remove ammonia from your tank, you would have to do a water change on your aquarium, otherwise, solely relying on carbon won’t help with anything.

When it comes to removing heavy metals in your aquarium, first, your tank must have no water in it, second, put water treatment inside the tank. After those steps, that’s the only time you can put water inside your tank.

How Long Do Sponge Filters Last?

There’s no exact measure for how long sponges would last because this would depend on the condition of your tank. A rough estimate of how long a sponge filter would last for a decade.

Sponge filters have a long life, especially if they’re being maintained properly and regularly. Do take note though that sponge filters would fall apart a lot quicker in hard water tanks.

Aside from that, sponge filters won’t have to be replaced, not until they’re breaking apart already.

Are Sponge Filters Noisy?

No, sponge filters aren’t noisy, they’re quiet filters thanks to their rubberized seals.

If you’re aiming for a goodnight’s sleep and don’t want to hear any noise coming from your aquarium, then a sponge filter will be your new best friend.

But since sponge filters are, well, filters, they will produce bubbles and these would slightly make noise, although nothing too loud. A solution in minimizing the noise from the bubbles would be to get a quieter air pump. If you don’t want to replace your air pump, then you can simply adjust the airflow of the air pump (for adjustable air pumps only).

Another solution to minimize noise from sponge filters would be adding air stones to your tank. These would make the bubbles smaller, therefore, your tank will be a lot quieter. For this method to work, you must ensure that there’s a gap beneath the air stone and the sponge filter.

Do You Have To Replace Sponge Filters

Yes, you have to replace sponge filters. If you don’t replace your worn-out sponge filters then it would not do an effective job of providing beneficial bacteria in your aquarium and there would be a significant amount of debris floating around your tank.

Like most filters, eventually, they need to be replaced. After sponge filters have served their purpose and are now looking like they’re about to fall apart, that’s the time when you need to replace them with new ones.

If they’re not yet falling apart, do retain these sponges in your tank so that the beneficial bacteria in them will not go to waste. As long as the sponge is still in one piece, then it’s still usable.

Do take note that sponge filters last a long time, usually decades, so there’s no need for you to worry about spending a lot of money on replacements.

Does A Sponge Filter Need A Lift Tube?

A sponge filter doesn’t need to have a lift tube as it can still function without it. However, if you want to control how the bubbles flow in your tank and have a consistent water current, then adding a lift tube to your sponge filter would be the best choice.

While it may not be necessary to have a lift tube installed with your sponge filter, it would be a great addition to the tank. This is because a lift tube offers two benefits; first, it would help reduce the noise coming from bubbles, second, it can increase the efficiency of air filters.

Can You Use A Sponge Filter In A Turtle Tank?

Yes, you can use a sponge filter in a turtle tank, be cautious though since turtles will nip at the sponges because of the trapped food particles in there. The solution for this would be to get a gutter guard and spray paint it with Rustoleum and Krylon.

After spray painting the gutter guard, wrap it around the sponge filter. This would protect the sponge from getting bitten by turtles, also, the two layers of spray paint would prevent corroding the gutter guard. Corrosion is toxic for your tank, so this is a vital step.

Make sure to spray paint the Rustoleum first and then add the Krylon after. This way, the Krylon would stick to the gutter guard (without Rustoleum as a first base the Krylon wouldn’t stick to the gutter guard).

Moreover, the Krylon is safe for your turtle tank and won’t leak any toxic chemicals.

Are Sponge Filters Good For Planted Tanks?

Yes, sponge filters are good for planted tanks. As for tanks that are heavily planted, they will only thrive in gentle water currents/movement, and this is exactly why sponge filters are great for planted tanks.

You’ll also have another benefit for having both a planted tank and a sponge filter, for instance, if you care a lot about the aesthetics of your tank the plants can cover the sponge filter so that it won’t ruin the look of your tank.

Are Sponge Filters Good For Turtles?

Sponge filters are good for turtles, especially when they are paired with powerheads instead of air pumps. It would also be recommended to have multiple sponge filters in a turtle tank since turtles defecate a lot and require more filtration to keep the tank clean.

Powerheads would make water flow a lot stronger, in turn, this would also allow a lot more water to be sucked in into the sponge filter. So overall, powerheads would increase the effectiveness of a sponge filter’s mechanical filtration.

The more efficient mechanical filtration is, the better it will remove debris and other gunk inside the tank.

However, it’s best to just opt for a HOB filter if you’re just going for a powerhead and a sponge filter. Opting for a HOB filter and taking out a sponge filter would provide more tank space for your turtles, and at the same time, make your tank look more appealing.

Are Sponge Filters Good For Cichlids?

Sponge filters would be good for Dwarf Cichlid fish, however, for larger species of Cichlid, a canister filter would be a better choice.

Most, if not all, Cichlids are messy fish and there’s a possibility that a sponge filter may not be able to handle the kind of mess these fishes release.

Compared to a canister filter, the mechanical filtration in a sponge filter is not as effective. Since mechanical filtration is in charge of removing waste from the tank (fish feces, debris, leftover food, etc.) it would be wiser to choose a filter that provides excellent mechanical filtration, and an example of that would be the canister filter.

Are Sponge Filters Good For African Dwarf Frogs?

Yes, sponge filters would be great for African Dwarf Frogs since these create gentle currents, and since this species of frog isn’t a great swimmer, gentle currents would be their preferred water flow.

Moreover, African Dwarf Frogs are small in size, so a sponge filter would be a great choice for them since these filters won’t suck them inside the filter itself.

Are Sponge Filters Good For Discus Fish?

Sponge filters are excellent for Discus fish since this species of fish defecates a lot. Sponge filters are known for being great at housing beneficial bacteria and that’s what Discus fishes need, especially since they produce a lot of waste.

Porous biological media is the recommendation for Discus fish and a sponge filter ticks that requirement. A sponge filter is a great home for beneficial bacteria and these filters last long too, so the beneficial bacteria will stay inside your tank for a long time.

Discus fish also prefer low water flow so a sponge filter would be an ideal filter choice as well since it creates gentle currents.

Is A Sponge Filter Enough For A 10 & 20 Gallon Tank?

A 10-gallon tank would need one sponge filter while a 20-gallon tank would need two sponge filters.

If you have a 10-gallon tank then the sponge filter should have a double outlet air pump if you’re not using them as primary filters. However, if you’re using sponge filters as your primary filter then it would be best to have two of them in a 10-gallon tank to increase its efficiency.

As for 20-gallon tanks, these would require two sponge filters each equipped with double outlet air pumps.

Of course, this would be the average requirement for a tank. The number of sponge filters you should have for both 10-gallon tanks and 20-gallon tanks would depend on what species of fish you’re keeping.

How Many Sponge Filters For A 30, 55, & 75 Gallon Tank?

20, 55, and 75-gallon tanks would need two or more sponge filters to accommodate these sizes. Also, larger tanks would require a lot more filtration and sponge filter capacity and more sponge filters would be able to do just that.

Again, the number of sponge filters would heavily depend on what species of fish you’re keeping in a tank. If you have fish that heavily defecate then you will need more than two sponge filters. However, there’s a downside to having sponge filters installed in a tank.

Large tanks, such as community tanks, house a lot of fish, then there are large tanks that don’t have a lot of fish in them but they do have one to two large fish. In this case, a sponge filter would only occupy space inside the tank, leaving a lot less space for your tank inhabitants.

The best filter option for larger tanks would be canister filters since these aren’t placed inside the tank because they’re external filters. This would provide a lot more tank space for your fish and plants.

Can A Sponge Filter Work Without An Air Pump?

No, a sponge filter won’t work without an air pump.

Sponge filters won’t be able to provide any oxygen inside a tank if there’s no air pump. The air pump is responsible for bringing in oxygen and this is why an air pump is an essential component that completes the function of a sponge filter.

Can You Reuse Sponge Filters?

Yes, you can reuse a sponge filter. Just remember to sanitize them every now and then before putting them back into your tank.

A sponge filter collects contaminants inside a tank and also houses beneficial bacteria. If you want to reuse sponge filters then you’re going to have to sanitize them first by removing the contaminants caught in the sponge.

Remember not to rigorously wash the sponge filter as this will wash away all the beneficial bacteria inside the sponge.

What Are The Most Popular Sponge Filters?

AQUANEAT Sponge Filter, AQUANEAT Double Bio Sponge Filter, and Hikari Bacto-Surge Foam Filter would be the most popular sponge filters.

All these sponge filters we’ve mentioned above are aquarist favorites and all have several positive reviews about them. Both AQUANEAT and Hikari are reputable brands for fish care so buying their products would be a great decision to make.

Check them out here:

AQUANEAT Sponge Filter

AQUANEAT Double Bio Sponge Filter

Hikari Bacto-Surge Foam Filter




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