How Often Should You Clean the Aquarium Sponge Filter?

Sponge filters are one of the earliest forms of filtration you can have for your aquarium. They came about around the same time as people took an interest in keeping fish in aquariums. With an influx of different filter systems in the market, many owners don’t know this kind of filter exists.

When it comes to using a sponge filter, there are a few instances when it isn’t the ideal option, yet in other cases, it is a perfect choice.

Like any filtration system, there is regular cleaning required. For new tank owners or fish lovers who have never used this filter type, they may be wondering.

How often should you clean the aquarium sponge filter? There are two particular answers to this. One says you need to clean your sponge filter every two weeks, and the other says you can clean it after several weeks. Both these answers are correct and for very different reasons.

By the end of this article, you will learn what sponge filters are, what you use them for, and how you maintain them. You will also see the plus sides and the downsides of using this simple kind of filter.

What is a Sponge Filter?

The name gives it away, and a sponge filter is precisely that. One thing that may not be obvious, to begin with, is these humble sponges carry out two forms of filtration as the aquarium water passes through them.

The first being mechanical filtration. Any debris or particles won’t be able to pass through the small pores, and thus clean water comes out of the other side. The second kind of filtration is biological filtration, where bacteria grow.

A sponge filter can come in various sizes as well as varying pore diameters, and by doing so, they are ideal to be adapted for varying filter requirements. Another great thing with these simplest of filters is you can power them by several methods. Powerheads, air pumps, or even another filter type are all-sufficient for powering these filters.

Best Uses for Sponge Filters  

There are two particular scenarios where these sponge filters are a great choice. Here you can see how tank owners use them in delicate situations.

Safe and gentle filtration

One of the best times you can use a sponge filter is when you have a fry tank. With a regular kind of filter, there is the possibility small fish will be sucked into the filter by the power of the water intake. When using a sponge filter, this isn’t possible as the fish won’t be able to pass through the pores of the sponge.

Betta fish can also benefit, they are not keen on strong currents, and the sponge acts as a buffer because the water can only pass as fast as it can make its way through the sponge. You can add to this the cases where you may have a hospital tank where you are keeping sick fish. A sponge filter is enough to keep water flowing and clean, thus aiding their recovery.

Another scenario is if you are setting up a new aquarium. Because you need to establish beneficial biological colonies, you can do this with the use of your sponge filter. The way of doing this is to run your filter for a few weeks before your new tank being setup.

Once you are ready with your new tank, you can take the sponge filter, which has had the chance to mature and place it in a sealable plastic bag that is full of tank water. You can add this to your new tank, where it will receive a boost and will reduce the ammonia levels and the nitrite spikes often associated with new tanks.

Because these don’t interfere with other filters, many tank owners run these as a secondary filter in case they need to use another tank in an emergency.    

Sponge Filters and Canister Filters

Another area you find these filter work well are as pre-filers for use in a canister filter. When you use them in this way, the nature of the sponge filters out the large debris and particle matter. This helps to stop the canister from clogging up.

The main reason this is so beneficial is that it is far easier to clean sponges than it is to clean your canister filter. You also find you gain additional biological filtration by using a sponge filter as the first step.

Experienced tank owners may use multiple sponge filters of different types to vary the mechanical filtering that is available. On top of this, you can stagger the cleaning, so not all filters will be out of the tank at the same time. This maintains many beneficial bacteria in the tank at all times.

Maintenance of Sponge Filters

While your sponge filters do need cleaning, you don’t want to clean them too much, or you will lose all the beneficial bacteria you have been culturing since the last clean. You will find, they are very easy to care for, and many tank owners use their filters to the point of them disintegrating.

Here you can see the best ways to clean these filters is when you perform a water change of your tank.

When doing so, save some of the aquarium water you have removed, and submerge the sponge. All you have to do is gently squeeze to dislodge the larger particles of dirt and grime. The main thing to do is clean the sponge enough so water can still pass through.

Squeezing too hard will dislodge all the parts that contain the beneficial bacteria, and you could damage your sponge in the process. To make sure your filter lasts as long as possible, you can do this operation every couple of weeks. Although, this isn’t vital if you use the filter as a secondary filter rather than as the main filter.

As we saw, some tank owners use multiple sponge filters. Either they stack them one on top of the other, or they use two inlets.

The best method of cleaning is to stagger your schedule, so you clean one, and then the other will be clean on the next scheduled water change or tank clean. To recap, this helps nitrite spikes, minimizes ammonia levels, and retains several beneficial bacteria.

You ought to know there can be a difference in the way you clean your filter. If you have one that is powered by a pump or powerhead, you will need to disconnect all the tubing. In the same way, you clean the impeller on a canister filter; you do the same for your sponge filter.

All service tubes need cleaning to remove any blocked debris. You may need a toothpick to remove these if they are wedged inside. One area, which may require changing, is the air filter if your pump comes with one.

If it needs changing, you can tell this by the discoloration of the foam or filter. The biggest concern with cleaning your sponge filter is to be sure it doesn’t dry out during its regular cleaning.


Sponge filters do have downsides, although these don’t affect their performance. The basic negative is they don’t offer any capability of chemical filtration. Many tank owners don’t regard this as a negative and think that mechanical and biological filtration, in most cases, is sufficient.

As long as your tank has plenty of mechanical and biological filtration in place, there isn’t any need for the other.

One other downside is the aesthetic qualities. A sponge filter is large and not as appealing to the eye as it protrudes from the top of your tank. Again, this isn’t so much a negative as a grip because you can hide this in one way or another.