The Benefits of an Aquarium Sponge Filter

 . in Pump & Filters

The Benefits of an Aquarium Sponge Filter

Sponge filters are important additions to fish tanks and are the only source of filtration method for many aquariums.  To decide if your aquarium could use one, you need to understand the different techniques used to filter water, how an aquarium sponge filter works, and the benefits it has for your fish.

To help you reach the best decision, we list everything you need, how to set up, and clean an aquarium sponge filter.  We give you four different types of sponge filters for you to decide which one is the best filter for you.  We give you some tips and even teach you how to make a DIY Sponge Filter.

Types of Filtration Methods

There are three types of aquarium filtration: mechanical, chemical, and biological. Mechanical filtration means physically cleaning the water in your fish tank to remove unwanted elements and particles, like uneaten food, fish waste, or algae. Chemical filtration is done with activated carbon, which absorbs unwanted chemicals and keeps the water crystal clear. Biological filtration is where your aquarium sponge filter comes to action; it refers to the good bacteria that grow on most surfaces, including the glass, substrate, and decorations, and is an essential part of the nitrogen cycle.

Many hang on the back filters implement all three types of filtration, improving the clarity of the water.  In the event of a power outage, the filtration stops.  For short periods this is not an issue for most fish tanks; however, for a long duration, it could cause some problems. 

For a crystal-clear fish tank, you need to turn over the water about 4 to 5 times per hour measured as Gallons Per Hour (GPH).

How Does an Aquarium Sponge Filter Work?

Air is forced into the center cavity, creating suction drawing water through the sponge and bubbles escape.  The surface area of the sponge catches particles, and the beneficial bacteria complete the nitrogen cycle.

The Benefits of an Aquarium Sponge Filter

  • The sponge protects small fish and fry from being pulled into the filter
  • The biological filtration works even with the loss of power; the nitrogen cycle continues as aquarium sponge filters keep good bacteria
  • Draws water from lower parts of the tank to increase water surface area and gas exchange of CO₂ for O₂
  • Using an existing aquarium sponge filter will speed up the cycling of a new tank by adding beneficial bacteria

Also read – The Best Tips on How to Lower Nitrates in Your Freshwater Aquarium

Other Than an Aquarium Sponge Filter What Else Do You Need

  • An air pump and air tubing
  • An airstone to break the bubbles into smaller ones reducing the bubble noise(recommended)

How to Set Up a Sponge Filter?

  • The parts you will need are a sponge filter, an aquarium airline tubing, an air pump, a check valve, a trainer and an airstone
  • Rinse your sponge with siphoned aquarium water allowing the air to release (squeezing a few times)
  • Rinse all parts off with the same water to clean it
  • Clip all parts together from top to the weighted base, step, strainer, sponge
  • You may need to cover the lift tube to prevent small fish from entering (water needs to escape)
  • Push the air tubing through lift tube
  • Attach the air tubing to the bullseye top of the strainer
  • Clip the lift tube and bullseye in place
  • Add airstone if you wish before clipping the bullseye on top by cutting the air tubing halfway into the sponge and pushing it onto the airstone
  • Place in your aquarium and let the airstone soak in water (if added)
  • Turn on the air pump
  • Adjust the airflow valve until you have the correct amount of current

You will know if the sponge filter is working if bubbles start floating to the top.

Tips:  Bullied fish may try and hide in the lift tube.  If the current is too strong for the type of fish you keep, they will tire, and this will lead to premature death.  You can cut air tubing and the lift tube to the desired height with scissors.

Placement of Your Aquarium Sponge Filter

You can place it in the center of your fish tank, and the sponge filter will draw in water from the whole tank; however, it looks untidy; placing it in the corner works well and is more discrete.  For larger aquariums, consider using smaller sponges in different locations.  They are easier to hide and increase the water flow throughout the fish tank.

Cleaning Your Aquarium Sponge Filter

Your aquarium sponge filter is the easiest fish tank filter to clean.  Remove and squeeze out the sponge filter with siphoned water every other week.  The other elements can be taken apart and brushed with siphoned water monthly or every second month, depending on the particles that accumulate in the area.

Aquarium Sponge Filters

The essential aspects of sponge filters for fish tanks are the size of the unit and if it will fit neatly into your fish tank; for most of us, the ability to hide it is quite important.

Best Aquarium Sponge Filters

#1 – Hydro-Sponge Filter


The Hydro sponge is a grey unit with vertical lines increasing the surface area.  It has five different size options, with variations in the design details.  No matter what decorations you have in your fish tank, you will find one that is easy to hide in your set up. These are your options:

  • The 10-gallon unit is the only short unit in the set and is about as wide as the 40-gallon unit
  • The 20-gallon group is the thinnest unit in the set
  • The 40-gallon unit
  • The 80-gallon unit
  • 125-gallon unit

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Our Verdict​

As you can guess, I love the 10 and 20-gallon options. Both can be hidden easily in your fish tank.  If you have broader plants and decorations, the 10-gallon units are easier to scatter across your fish tank. If you have taller plants, the 20-gallon units work better.  For fish tanks with limited decorations, I would use two or one large sponge rather than smaller units.

#2 – Aquapapa Pack of 2 Bio Sponge Filter



The Aquapapa pack of 2 bio sponge filters is a large but neat unit that attaches to the glass of your fish tank with two suction cups.  It has two adjustable arms that allow you to move your sponges forward.  Two clips hold the air tubing in a line down the side of the unit.



Our Verdict

Two smaller units will give you more or less the same surface area for bacteria and alternate cleaning ability the duo sponge aquarists love, and you can hide it better and move it to cycle a new tank.

#3 – Lefunpets Biochemical Sponge Filter



This aquarium sponge filter is a neat little unit with vertical slots that increase the sponge surface area.  The base and sponge align neatly and is available in 4 different aquarium sponge filter setups suitable for all tanks.

  • Small 2” W x 4.75” H (round)
  • Medium 2.95” W X 4.72” H (triangle for a snug fit in the corner)
  • Large 3.5” W X 6.3” H (round)
  • X large 4,7”W X 7.94”H(round)



Our Verdict

The con is a common problem with aquarium sponge filters; many are black, and the grey ones perform only mildly better.  The large and X large sizes are too big for me as I prefer placing 2 or 3 small sponges into larger tanks.  The medium one for a corner placement looks neat and tidy.

#4 – Aquatop Aquatic Supplies Classic



This aquarium sponge filter is a small aquarium filter I found and is perfect for small fish tanks. It is weighted with a rock tub at the bottom, which adds additional surface area.  It feels a bit clumsy. Burry the bottom into your substrate, and its height of only 3.1”, is smaller.



Our Verdict

I wouldn’t use this in larger tanks. It is uncomfortable to use and moves around if not buried, and your diggers will unbury it.  The surface area is limited, but for tanks under 5-gallons, this nano sponge is the only one I would choose; even in an isolation tank, it is cheap enough to discard.

#5 – QANVEE Fluidized Moving Bed Filter



This aquarium sponge filter is based on the popular homemade moving bed filters with an additional sponge filter hidden at the intake filter.  Water flows through the sponge into the main container.  Moves the media around and releases clean water on the other side.



Our Verdict

It circulates and cleans the water well. Bubbles float on top of the fish tank and disappear quickly.  If you want bubbles in your tank, you will have to have a bubble decoration.  I like bubbles, but for hobbyists who wish to an aquarium sponge filter for cleaning and circulating the water, this one is perfect.

#6 – UPETTOOLS Aquarium Biochemical Sponge Filter



This neat little product combines the floating bed with an aquarium sponge filter. It sucks in the water through ceramic bio media and a long sponge with deep horizontal cutouts.  This sponge filter has two variants:

  • Single-arm unit
  • Double arm unit



Our Verdict

The best part of this product, which is available on other aquarium sponge filters, is it gently pours the water into your fish tank if the water outlet is high enough.  If you place the outlet pipe out of the water, your fish can’t swim in it.

FAQ’s on Aquarium Sponge Filters

Why Does the Sponge in My Fish Tank Filter Start to Float to the Top? There are a few options.  If it is new, and the sponge filled with air, squeeze it in fish tank water until all the air bubbles stop coming out.  There is not enough load in the base weight to push it into the substrate a little.  If this problem persists, add a stone to the underside of the base of the aquarium sponge filter, secure with silicone and allow it to dry overnight.

How Often to Clean Aquarium Sponge Filter? The frequency of cleaning aquarium filter depends on the bio-load of your fish tank; if it’s high, you may have to rinse the sponge out weekly or every second week.  If your tank is stable, you can go as far as monthly.  Use a little bit of aquarium water to squeeze out all the muck.

How to Make a Sponge Filter? A DIY aquarium filter is simple to do but will not look as lovely as a store-bought one. The items you need to make a sponge filter are stone or broken tile, PVC cap and pipe, silicone, air tubing, an aquarium sponge, and a drill.

Start with a base that can be anything substantial that will not leach chemicals into your aquarium like a rock or broken tile etc. Silicone a PVC cap onto the plate and allow it to sit overnight to dry.  Mark holes into your PVC pipe with a drill.  Push the filter sponge over the PVC pipe (cut it with scissors if you need to).  Push the air tubing into the first hole on the PVC pipe and silicone to seal around the edges and allow it to dry overnight.  Attach the air tubing to an air pump; a check valve and airflow valve are also recommended.  The finer the pores of your sponge, the more particle matter and surface area it has.

Aquarium Pumps and Filters Go Hand in Hand

The aquarium sponge filter only functions with an air pump.  But you can have one pump controlling many sponge filters.  Most sponge filters will need an additional airstone to control the bubble noise, which can be annoying.

All aquariums should have an aquarium sponge filter to circulate the water near the bottom of the tank, but what about another chemical filter? I would always over filter rather than under filter.  Although many aquariums do run successfully without a carbon filter, they do improve water clarity and color and help keep your fish tank cleaner, and that is always a winner for me.

Check out – The Best Freshwater and popular Saltwater Aquarium Fish for a 55 Gallon Tank

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