Why you Need a Pre-Filter Sponge for Your Aquariums

Why You Need a Pre-Filter Sponge for Your Aquariums

Are you looking for an easy and cost-effective way to optimize hang-on-back or canister filters? 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 offer surprising 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. Large openings in the filter intake tube can allow large objects to be sucked up and potentially damage 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 because dirty filter media can cause problems in the system. We would rather have an intake sponge that we can easily clean than filter media that has been buried inside a canister filter.

Prefilter sponge is installed at the tip of a filter intake tub

Which Pre Filter Sponge Should I Get?

There are three sizes to choose from: medium, large, and mini. We purposefully designed our sponges with coarse foam with a greater 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:






Quietflow LED10

Quietflow LED 20

Quietflow LED30

Quietflow LED 50


Quietflow 75 LED

Aquaclear 20

Aquaclear 30

Aquaclear 50

Aquaclear 70

Aquaclear 100

Use an O-ring, zip tie, or extra sponge to make it stay




Use a zip tie to make it stay









Slim S10

Slim S15


Slim S20


Emperor 400

Penguin 75

Mini or Medium

Penguin 100

Penguin 150

Penguin 200

Place the intake basket over it



Penguin 350

Remove basket and use an O-ring or zip tie to make it stay

Tidal 55

Tidal 75


Tidal 110


WhisperIQ 20 / 30/ 45

Whisper EX20

Whisper EX 30

Whisper EX 45



Whisper EX 70



To make it stick, use a thick zip tie or O-ring.

To transform our powerhead into a mini-power filter, a prefilter sponge can be attached to it. Simply attach two zip ties on the powerhead’s intake tray, trim the tails, then slide on the large prefilter sponge.

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. The prefilter sponge should be positioned on the intake tube partially so that it only covers the tube’s tip. The sponge should be positioned at the very end of the intake tube so that water travels more evenly through the entire sponge and the foam does not get clogged up as quickly.

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

1. You can make the sponge smaller by using one of these methods:

An O-ring kit with many sizes is available. Place an O-ring that fits snugly on the intake tube about 1-2 inches (22.5-5 cm) away from the tube’s end. The O-ring should be placed on the tube. Slide the prefilter sponge over it. Attach a plastic zip tie around the intake tube’s end, approximately 1-2 inches (22.5-5cm) from the opening. The buckle should still be attached to the tail. For a snug fit, slide the sponge onto the zip tie attached to the intake tube. 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 to the End of an Intake Tube to Keep the Intake Sponge from Slipping

Even if your intake tube is not the most common shape, you can still make a DIY prefilter sponge. Use a sponge pad to cut a piece of sponge that you can either place inside your intake basket, or wrap it around the entire intake using zip ties.

To see a video demonstration of how to install and properly fit a prefilter sponge, watch our tutorial here.

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. Once a month or whenever you see the water output of the filter has decreased, make sure to “empty the trash” and clean your pre-filter sponge.

1. To scoop out the sponge from the water, use a plastic bag. This will ensure that it doesn’t spread to the aquarium and cause a mess. 2. Squeeze and wring out the sponge several times in old tank water inside the plastic bag. 3. The water that is dirty acts as mild fertilizer for plants. If you are able to, then pour the water onto the lawn or a houseplant. 4. Continue repeating Steps 2 through 3 until water in the bag is no longer very dirty. 5. Place the prefilter sponge back on the intake tube. 6. If there are lots of particles floating in the water, just wait an hour or so for the filter to clean it up again.

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. For beginners, our aquarium filter guide will help you choose the right filter for your tank.