Comprehensive Guide About Sponge Filters – How Does A Sponge Filter Work

Sponge filters are becoming popular day after day because of their exceptional and beneficial work. Sponge filters are the best and most dependable products when gentle and safe filtration is required.

It offers the best surface agitation and good water circulation to eventually prevent sucking up the shrimps, fish fly, and slow-moving creatures in aquariums.

Overall, they are primarily used in fish tanks with breeding facilities, and fish rooms because they are cost-effective and reliable. But how does a sponge filter work? This is among the frequently asked questions by many of us, among others.

Fortunately, I have deep-researched and come up with a comprehensive and detailed guide to help you understand more about sponge filters.

So, without further ado, allow me to take you through the article, answering the necessary questions to provide you with helpful information.

What Is Precisely A Sponge Filter?

A sponge filter is designed to offer two categories of filtration. Generally, this is a helpful filter that utilizes an air pump and sponge to effectively draw aquarium water via the porous sponges. Besides, this specific action filters the fish tank.

The first filtration process comes in handy when the sponge begins growing an active bacteria colony, and this offers a vast surface area for bacteria to grow. The second filtration is mechanical filtration, which comes in handy when wreckages get in the sponge.

Besides, sponge filters are frequently valuable for most fish tanks because they are perfect due to their safe and gentle flow. And this allows them to effectively collect the physical debris right from the aquarium; further, they also offer biological filtration.

Anatomy of a sponge filter

Will I Require An Airstone For My Sponge Filter?

The simple answer is yes. What is an air stone? This is a weighted small accessory that tends to diffuse the air from right from the user’s air pump to small bubbles into the water.

Therefore, the experts recommend that it is essential to add air stone inside of your sponge filter to effectively lessen the bubbling noise as well as make the entire filtration more effective.

Generally, the air stone is designed to create a very stable stream of small bubbles rather than intermittent, large bubbles. And this offers constant lift on your sponge filter while offering better water circulation.

Further, adding air stone also aids to keep the water cleaner, and offers your fishes with enough oxygen among other related benefits.

Read more: How To Increase Oxygen In A Fish Tank?

How To Perfectly Set Up My Sponge Filter?

In essence, the way you set your sponge filter matters a lot. Besides, you can locate your sponge filter under the substrate of inside aquarium walls.

Similarly, setting up sponge filters becomes challenging for many, and you might destroy the entire setup with one mistake. Luckily, I have provided the below-detailed steps on how to perfectly set your sponge filter:

  • Check All Components: First, ensure you got all the necessary components. And this comprises the check valve, air pump, airline best lift tube, sponge filter itself, or air stone. You should have every part because if anything misses can cause the entire structure to fail.
  • Spread every item on the floor: Take your sponge filter apart; remove the plastic strainer located inside the foam. Besides, spreading everything on a clean floor /table will help you know anything missing.
  • Connect Air Stone: Now detach the specific bullseye right from the top of the strainer, followed by replacing it with a quality airstone right at the bottom of the filter. Further, connect your air stone at the center of the bullseye via airline tubing in short length. Besides, in some cases, the sponge filter might be too small for the tubing to perfectly suit, so you should connect your airstone directly to the bullseye.
  • Connect With The Base: Next, attach your bullseye to the strainer, followed by returning it to the bottom. And to ensure this foam will firmly stay on the bottom, consider connecting the specific strainer to the weighted base, which is usually delivered with a sponge filter. The sponge filters operate well right from the bottom, where more contaminants settle.
  • Attach Lift Tube: Take the lift tube starting from a specific end of the airline tubing; attach it to the center of the bullseye top. Attach it firmly inside out in order for everything not to loosen after filtration begins.
  • Place in the aquarium: Now, immerse your assembled sponge filters in the aquarium, and squeeze out the air bubbles which might get trapped inside the foam. And this aids the filter foam in eventually sinking into the bottom because everything might fail if some air gets trapped within it.
  • Connect the air pump: Turn your attention right to the air pump. However, consider making detailed cuts on airline tubing that will be enough to typically reach your sponge filter into the water. And after attaining the correct length, now connect the specific air pump to the sponge filter.

Where you will position your pump is much essential. When located below the top of your tank, this means the water will effectively flow back to the airline tubing when this pump is off.

And to stop this, install the check valve to avert this backflow. Ensure the check valve end is typically indicated via a colored horizontal line and facing the air pump direction.

Finish your set with the addition of the drip loop suitable power cable running your air pump. Essentially, this wills top moisture not to come into contact with your power cable because this can be disastrous.

Now tune on your air pump, and see if bubbles will emanate from the sponge filter immediately, and this is a sign that your whole setup is perfect and successful.

Why Are The Bubbles Coming Out On The Sponge Side?

There few reasons why this could happen:

(1) First, maybe you removed or shortened the lift tube. Generally, a shorter lift tube will not have enough suction to pull bubbles up on the center column; some bubbles will escape.

(2) When air pressure from the air pump is too intense, excess air will be forced into the sponge filter causing extra bubbles to leak out on the sides.

(3) If the air stone is also crooked inside your sponge filter, you should shorten the tubing, attaching the air stone right to the bullseye to eventually hand straighter.

What Are The Benefits Of Investing In A Sponge Filter?

Benefits Of Sponge Filters In Aquariums

(1) They Are Easily Replaced And Repaired When Damaged

Sponge filters are also hard to damage because they are made with superior quality components; sponge filters are as modest as they are delivered. Besides, most issues come along the decaying sponges, and lines of the cracked plastic, and both are easy to notice and replace.

(2) They Are Perfect Pre-Filters

Instead of running different units such as a canister filter, a sponge filter is the ideal product to preserve your shrimp and small fish and get excellent and safe chemical filtration.

(3) Gentle Current

This product is perfect for our aquariums when we require using incredibly gentle current; they offer biological and mechanical filtration, not endangering the animals. When you raise brine shrimp, fish fry, and other related small aquatic organisms using inappropriate powered filtration will suck them and kill them.

(4) So Quiet

Sponge filters are quiet enough without any disturbance even to the lightest sleepers. Even if they sometimes have surface agitation sound similar to miniature waterfalls, users find it relaxing compared to other related filter styles.

(5) Can Get Used To Different Types Of Aquariums

Saltwater, planted aquarium, freshwater, brackish, shrimp–only, and other related can effectively work well with the same sponge filter. The giant aquarium and the more fish you have, the larger the sponge filter you should invest in, period.

(6) Faster And Easy To Clean

These products are easy and quick to clean because dirt is part of the plea. It is a matter of removing the sponge filter and other related accessories; use a bucket of water and clean without endangering the bacteria colony.

(7) They Operate Even During Power Outages

Sponge filters continue actively operating when powers go off, breaking down all waste and revitalizing in that outage. No matter how long the light might take, the good bacteria will not die off entirely.

How To Clean The Sponge Filter?

Clean the sponge filter is the most straightforward task with the below supportive guide:

(1) Best Tactics For Cleaning A Sponge Filter

  • Always turn off the power to the air pump.
  • Consider cleaning one sponge filter at a time, probably if it is a dual sponge filter.
  • Avoid squeezing your sponge much long; generally, spend about 45 and 30 seconds when cleaning it.
  • Use two water containers if your sponge filter is too dirty.

(2) Fill Your Container With Aquarium Water

The perfect time to effectively clean your sponge filter is after or during changing water. Once you have removed the sponge filter, aquarium water may become a bit cloudy but get clear within two or one hour. 

In this case, avoid using tap water since it contains some Chlorine that might entirely destroy the good bacteria, so use aquarium water. 

Further, keep your aquarium accessories separate and avoid using them for any other purpose because they may have chemicals that might be toxic to your fish.

(3) Clean The Sponge By Squeezing It In The Container Of Water

First, brush off the surface debris clinging to the outer layers; squeeze the sponge until it stops releasing the yucky water. This might take around 5 and 30 seconds based on your sponge size and how dirty it might be after sucking the fish food and waste. 

However, if your sponge is dirty, consider using two water containers; once your sponge is tidy, consider quickly putting it back and turning on your filter.


Sponge filters are essential additions to the fish tanks. They are a perfect and dependable source of filtration for many aquariums.

To help you understand more about sponge filters, I have listed the necessary information above, including how to clean, and how to set, among other related information.

Please don’t hesitate to put a comment if you have anything to add. 

Sujit Modak

Leave a Comment