Sponge filters are one of the most popular filters used in fish stores, fish rooms, and breeding tanks because they’re so reliable and easy to use. But beginners often have many questions on how they work, how to set one up, and how to keep them clean. Check out our step-by-step instructions to help you get started with your first sponge filter.
Sponge filter setup diagram
The air pump pushes air through the tubing into the hollow cavity inside the sponge filter. Bubbles rise from the inside of the sponge, thus drawing water through the sponge walls. This water suction process mechanically collects debris from the aquarium and gives beneficial bacteria place to grow.
Sponge filters are a long-time favorite of both beginner and veteran fish keepers since they’re cheap, easy to clean, and hard to break since they have very few mechanical parts. Because of the constant bubbling, it provides good water circulation and surface agitation, white being gentle enough to avoid sucking up fish fry, shrimp, and other slow-moving creatures. Plus, during power outages, the beneficial bacteria on the sponge stays in the oxygenated tank water (which gives it a longer chance of surviving), and you can even purchase a battery pack backup that works with our USB air pump in case of emergencies.
For more information on filtration options, read our article on fish tank filters and which one you should get.
An air stone is a small weighted accessory that diffuses the air from your air pump into smaller bubbles in the water. We recommend adding an air stone to the inside of the sponge filter to lessen the bubbling noise and make the filtration more efficient. The air stone creates a steady stream of tiny bubbles (instead of large, intermittent bubbles) that produces constant lift in the sponge filter – much like a continuously running escalator (versus an elevator that starts and stops all the time).
There are several reasons why this could be happening, so try checking the following:
Sponge filters are a pretty basic piece of equipment, so there’s not a lot of difference between brands. However, after a decade of using tons of sponge filters, we made our own with all the improvements and features that we’ve always wanted. We designed the base and lift tube with a green color to blend in with planted tanks and easily hide green algae growth, whereas the foam sponge is black to best conceal fish waste and detritus that gets sucked in.
The sponge is made with a coarse foam of 20 ppi medium porosity to easily collect particulate from the water without clogging up too quickly. The surface area is ideal for shrimp and fish to graze on and clean. Plus, the coarse sponge doesn’t trap as much air, allowing it to get nice water flow and sink immediately. (Fine sponges often have problems with floating, which can cause lack of oxygen in your aquarium and potentially loss of life.)
All of the sponge filters we sell are hollow inside and tall enough so that you can install an air stone inside for more efficient filtration and quieter bubbles. Also, if you remove the lift tube, you can connect another sponge filter on top (without its base) to increase filtration capacity. These sponges can be customized in multiple configurations, since three of the sponge sizes (all except for the nano sponge) can be mix and matched together. The advantage of stacking multiple sponges (versus running them separately) is that they can run off a single air pump line. Then, if you ever need to set up a hospital tank, simply remove one sponge from the stack and it’s already seeded with beneficial bacteria to help the quarantined fish.
Yes, a sponge filter helps to clean your aquarium, but it’s essentially like a trash can that collects waste and needs to be emptied out every once in a while. We recommend cleaning your sponge filter once a month or whenever you see a decrease in bubbles (which is caused by the foam getting clogged up with detritus).
Sponge filters are easy to use, budget-friendly, and very reliable compared to other filter types. If you haven’t tried one yet, check out our line of sponge filters and let us know what you think!