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 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. There are many benefits to intake sponges, including:

– 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 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 is installed at the tip of a filter intake tub

Which 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. Our pre-filter sponges don’t remove very fine particles but they can block out all other sizes of particles and won’t get clogged as fast. 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 LED20

Quietflow LED 30

Quietflow 50 LED


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

Mini 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 EX 30

Whisper EX 45



Whisper EX 70



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

A pre-filter sponge can also be used with our power head to transform it into a mini power filter. 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. If the filter’s intake tube has a large basket that is much wider than the tube, then remove the basket. 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 tube. This prevents the intake sponge’s slippage

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

You can get an O-ring set that includes many sizes. 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. 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. Make sure the buckle is still attached by removing the tail. Slide the sponge onto zip tie on the intake tube for a very firm fit. 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. 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.

Watch our tutorial to see how to properly fit and install 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. 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. Use old tank water to squeeze and wring the sponge out several times inside the plastic bag. 3. The dirt water acts as a mild fertilizer, so if you can, pour it onto your 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 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.