Sponge Filters: The Easiest Fish Tank Filter Ever

Sponge Filters: The Easiest Fish Tank Filter Ever Because sponge filters are so reliable and simple to use, they are a popular filter in fish shops, fish rooms, breeding tanks, and fish houses. Many people …

Sponge Filters: The Easiest Fish Tank Filter Ever

Because sponge filters are so reliable and simple to use, they are a popular filter in fish shops, fish rooms, breeding tanks, and fish houses. Many people are unsure how sponge filters work and how to clean them. Check out our step-by-step instructions to help you get started with your first sponge filter.

Sponge filter setup diagram

What is a Sponge Filter?

This filter is the most basic. It requires at minimum three components: a sponge filtre (which sits within the tank), an air pump (which sits out of the tank), and airline tubing that connects them. Air is pushed through the tubing by the air pump into the sponge filter’s hollow cavity. The sponge walls are drained by bubbles rising from the sponge. This water suction process mechanically collects debris from the aquarium and gives beneficial bacteria place to grow.

Because they are simple and inexpensive, sponge filters are a favorite among both novice and veteran fish keepers. It provides water circulation and surface agitation through constant bubbling. White is gentle enough to not eat shrimp or fish fry. You can also purchase a backup battery pack that will work with our USB pump to keep your sponge alive during power outages.

Find out more about the filtration options available in this article on fish tank filters. We also have recommendations on which type of filter you should use.

Do I Need an Air Stone for Sponge Filters?

An air stone is small, lightweight accessory that helps to diffuse the air from the pump and create smaller bubbles in water. To reduce the noise from the sponge filter and increase efficiency, we recommend that you add an air stone inside. The air stone produces a steady stream (instead large, intermittent bubbles), that creates constant lift in the sponge filter. It is similar to an escalator that runs continuously (versus an elevator that stops and starts all the time).

How to Set up a Sponge filter

1. Remove the sponge filter from the foam and the plastic strainer.

1. Take the bullseye off the strainer and place the airstone at the bottom. A small length of airline tubing can be used to connect the air stone to either the bullseye’s nipple, or the center. If the sponge filter is very small, you can simply connect the air stone directly to the bullseye. 2. Attach the bullseye to the top of your strainer. Then, place the strainer back in the foam and connect it to the sponge filter’s weighted base. 3. Slip the lift tube over one end of the airline tubing roll and connect the airline tubing to the nipple on the top of the bullseye. Then snap the lift tube onto the bullseye. 4. Place the sponge filter into the aquarium and squeeze out any bubbles from the foam if it’s floating. 5. The air pump should be placed in the tank’s final position. Next, cut the airline tubing (attached with the sponge filter) to the right length. Connect the sponge filter’s newly cut air tubing to the air pump. 6. If the air pump is located below the top of the aquarium, you need to add a check valve to prevent water from flowing into the airline tubing whenever the air pump is turned off or the power is out. Cut the airline tubing (between the sponge filter and air pump) a few inches outside of the aquarium, and then attach the check valve in between so that the end of the check valve with the flapper (looks like a colored or horizontal bar usually) is facing the air pump. If you place it backwards, it will not flow air when you turn on your air pump. Instead, flip it over.

1. To prevent moisture from getting into the plug, create a drip loop using the power cable. Then plug the pump in. In a matter of seconds, bubbles should start to form from the sponge filter.

Why Do Bubbles Come Out of the Sponge Side?

There are several reasons why this could be happening, so try checking the following:

– Did you reduce or remove the lift tub? Because a shorter lift tube doesn’t have as much suction pulling bubbles upwards the center column, some air can escape. – Is the air stone crooked inside the sponge filter? To make it hang straighter, you may need to shorten the tubing attaching the air stone to the bullseye. – Is the air pressure from the air pump too strong? If a bunch of air is forced into the sponge filter, excess bubbles may leak out the sides.

Which sponge filter would you recommend?

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 of a coarse foam at 20 ppi with medium porosity. It can easily collect particulate and prevents it from clogging up. The sponge’s surface is large enough for shrimp and fish to enjoy. 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.)

Our sponge filters are hollow inside. They can be stacked high enough to accommodate an air stone. To increase the filtration capacity, remove the lift tube. You can customize these sponges in many configurations. All three sizes of sponges (except the nano sponge) are interchangeable. A stacking of sponges is more efficient than running them individually. They can all run on a single line of air pump. 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.

How to clean a sponge filter

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).

1. When taking the sponge filter apart, disconnect the bullseye from the strainer (i.e., take off the whole top part of the filter) so you can easily remove the foam part for cleaning. 2. Use a plastic bag to scoop the foam out of the water so that the detritus won’t spread and make a big mess in the aquarium. 3. Use old tank water to squeeze and wring foam out. 4. Put the sponge filter back into the tank. 5. You can wait for the sponge filter to remove any large particles that are floating in the water.

Sponge filters can be very cost-effective and reliable, making them a great choice for budget-minded users. If you haven’t tried one yet, check out our line of sponge filters and let us know what you think!