Why you Need a Pre-Filter Sponge for Your Aquariums


Why You Need a Pre-Filter Sponge for Your Aquariums

Are you looking for a quick and easy way of optimizing your hang-on back (HOB) filter or canister? Pre filter sponges (or intake sponges) are a simple way to optimize your hang-on-back (HOB) or canister filter. The simple foam cylinder comes with a hole in its middle. This allows you to slide it on the intake tube of your filter much like a sock. Why would we need a prefilter sponge if we already have an aquarium 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 adds more mechanical filtration, thus keeping your filter media from getting dirty as quickly. This is important because dirty filter media does not function as efficiently, and we would much rather clean an easy-to-remove intake sponge than the filter media buried deep inside a canister filter.

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. These pre-filter sponges are not able to remove fine particles. However, they will still block out other sizes of particles and won’t become 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 LED 10

Quietflow 20 LED

Quietflow LED 30

Quietflow 50 LED


Quietflow LED 75

Aquaclear 20

Aquaclear 30

Aquaclear 50

Aquaclear 70

Aquaclear 100

Make it last by adding an O-ring and a zip tie or sponge.




To make it stick, use a zip tie









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

Use an O-ring, or zip tie to secure the basket.

Tidal 55

Tidal 75


Tidal 110


Whisper IQ 20 / 30 / 45

Whisper EX20

Whisper EX 30

Whisper EX 45



Whisper EX 70



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

To transform our powerhead into a mini-power filter, a prefilter sponge can be attached to it. Just attach two zip ties to the powerhead’s intake basket, cut off the excess tails, and slide on a 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. Slide the prefilter sponge partially onto the intake tube so that it is just covering the tip of the tube. 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.

O-ring attaches to the end of an intake tub to keep the intake sponge in place.

1. To make the sponge fit better, you can use the following methods:

An O-ring kit with many sizes is available. Locate an O-ring which fits comfortably on the intake tubes and place it approximately 1-2 inches (2.5-5cm) from the end. Slide the pre-filter sponge over the O-ring on the tube, and the sponge should stay put. Use a zip tie to secure the tube around the intake tube. It should be about 2 inches (22.5-5 cm) away from the opening. The buckle should still be attached to the tail. To ensure a tight fit, attach the sponge to the intake tube with a zip tie. – Use a small rectangular of coarse sponge to slip inside the intake sponge. Place the intake sponge on the tube and ensure it is securely in place.

Zip tie attached to the end of an intake tube. This will keep the intake sponge in place.

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 intake using zip ties.

Our tutorial shows you how to correctly fit and install prefilter sponges.

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. If the water output of your filter is decreasing, or once a month, you should “empty the trash” to clean your prefilter sponge.

1. You can scoop the sponge out with a plastic bag. 2. Put the sponge in a plastic bag and squeeze it several times. 3. The dirty water can be used as a mild fertilizer to plants. So, if possible, use the dirty water to water a lawn or houseplant. 4. Repeat Steps 2 and 3 multiple times until the water inside the bag is not very dirty. 5. Place the prefilter sponge onto the intake tube. 6. If the water has a lot of particles, you can wait for the filter time to clean it 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 aquarium filter.