Why you Need a Pre-Filter Sponge for Your Aquariums

Why You Need a Pre-Filter Sponge for Your Aquariums You are looking for an easy way to optimize your hang on-back (HOB), or canister filter. Pre filter sponges (or intake sponges) are a simple way …


Why You Need a Pre-Filter Sponge for Your Aquariums

You are looking for an easy way to optimize your hang on-back (HOB), or canister filter. Pre filter sponges (or intake sponges) are a simple way to optimize your hang-on-back (HOB) or canister filter. This foam cylinder is simple and has a hole at the center that allows you slip it onto your filter’s intake tube. It works much like a socks. What good is a prefilter sponge? We already have an aquarium tank filter. Intake sponges have a surprising number of benefits, such as:

– They provide more surface area to grow beneficial bacteria, which purify the waste chemicals in the water and make it safe for your fish to live in. – The filter intake tube often has large openings that allow sizable objects to get sucked up by the filter, potentially ruining the motor. The pre-filter sponge prevents things like baby fish, dwarf shrimp, little snails, plant leaves, and fish food from entering the filter. An intake sponge increases mechanical filtration to keep your filter media clean. This is crucial because dirty filter medium can make it less efficient and we’d rather clean an easy to remove intake sponge than the filter material buried in a canister.

Prefilter sponge installed at the end of a filter intake tube

What Pre Filter Sponge should I get?

We offer three sizes of sponges: small, medium, and large. Our sponges are made with coarse foam, which has a higher porosity. This means that our pre-filter sponges do not remove super fine particles, but they block out most other particle sizes and won’t get clogged up as quickly. Our mini pre-filter sponge is best for smaller fish tanks and filters with slow flow, whereas the large pre-filter sponge is well-suited for bigger aquariums and filters with fast flow. To help you select the right size, see our chart that lists some of the most popular filters in the fishkeeping hobby:




Pre-Filter size


Quietflow LED 10

Quietflow LED 20

Quietflow LED 30

Quietflow LED 50


Quietflow LED 75

Aquaclear 20

Aquaclear 30

Aquaclear 50

Aquaclear 70

Aquaclear 100

To make it stick, add an O-ring or zip tie to the sponge.




Zip tie it to keep it in place









Slim S10

Slim S15


Slim S20


Emperor 400

Penguin 75

Miniature or medium

Penguin 100

Penguin 150

Penguin 200

Overfit the intake basket


Penguin 350

To make the basket stay put, remove it and attach an O-ring/zip tie.

Tidal 55

Tidal 75


Tidal 110


WhisperIQ 20 / 30/ 45

Whisper EX20

Whisper EX30

Whisper EX 45



Whisper EX 70



Make sure it stays put with a thick O-ring and/or zip tie

Our power head can be transformed into a mini power filter by using a pre-filter sponge. Attach two zip ties to your powerhead’s intake basket. Cut off any tails and then slide on a large prefilter.

How to Install a Pre-Filter Sponge

1. Remove the basket if the filter’s intake tube contains a basket that is larger than the tube. 2. Place the prefilter sponge on the intake tube, making sure it covers the entire tube. Place the sponge at the very tip of the intake tube to ensure that water moves more evenly and foam doesn’t get clogged.

Oring to attach on the end an intake tube to prevent the intake sponge slipping

1. If the sponge is too large for the intake, use one of the following methods to make a tighter fit:

You can get an O-ring set that includes many sizes. Find an O-ring that snugly fits on the intake tube, and position it about 1-2 inches (2.5-5 cm) from the end of the intake tube. The pre-filter sponge can be placed over the O rings on the tube. Attach a plastic zip tie around the intake tube’s end, approximately 1-2 inches (22.5-5cm) from the opening. Make sure the buckle is still attached by removing the tail. To ensure a tight fit, attach the sponge to the intake tube with a zip tie. Cut a small rectangle from the coarse sponge pad and place it inside your intake sponge. Slide the intake sponge onto the tube, and make sure it fits securely.

Zip tie attached on the end of an intake tube to keep the intake sponge from slipping

You can make your own prefilter sponge if the tube is unusual. Buy a coarse sponge pad and cut off a section of sponge to a) stuff inside the intake basket or b) wrap around the entire intake and attach using zip ties.

You can watch our video tutorial to learn how to fit a prefilter sponge.

How to Clean a Pre Filter Sponge

The intake sponge is essentially like a trash can that collects fish waste, old food, and other debris in the water. You should empty the trash can once a month. Also, clean the pre-filter sponge.

1. You can scoop the sponge out with a plastic bag. 2. You can squeeze the sponge and then wring it out in the old tank water. 3. The dirty water is like a mild fertilizer for plants, so pour the dirty water onto a houseplant or the lawn if possible. 4. Continue repeating Steps 2 through 3 until water in the bag is no longer very dirty. 5. Place the prefilter sponge on the intake tube. 6. You can wait for the filter to remove any particles that are still in the water.

Adding an intake sponge to your filter is an easy way to upgrade your mechanical and biological filtration, while protecting your baby fish and invertebrates from getting sucked up. Our aquarium filter guide is a great resource for beginners if you don’t know which type of aquarium filter to choose.