What is an aquarium sponge filter?

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What’s a aquarium sponge filter and what is it used for?

A sponge filter is simple, but one of the most effective ways to provide filtration for aquarium water. It’s also a form of filtration, which is often overlooked by many aquarium keepers. This is due to the fact they are so simple and appear unnecessary. This article is based on successful use of these filters for over 40 years now.

A sponge filter is a porous type of material, which draws water towards and through the sponge. As water passes through the sponge, larger debris is blocked from entering the sponge and only small particles will be let through. This is also the part of the debris, which contains good bacteria and is used within the aquarium to get and keep the water cycled.
Because of the nature of how the porous material is designed, these sponge filters can hold a very large amount of this good bacteria.

This good bacteria is known as aerobic bacteria, which lives in the pores material and feeds on nitogenous ammonia and nitrites waste suspended in the water.

how a sponge filter works, beginner

Close up view of a patented AAP Hydro Sponge Filter, showing the pores and higher bio and debris trapping capacity of these unique sponge filters. This particular sponge is quite full of organic debris based on this close up inspection, an amount that would stop effective flow with most of the common knock offs.

AAP Sponge Filter videos at the end of this article.

How do they work?

Water is pulled through the filter media one of two ways. If using an air pump on a sponge filter, the water is drawn into the filter by lift, which is caused by air bubbles floating up from the pump. These bubbles lift the water up and out of the lift tube attached to the filter. This is cause for a nice easy circulation around the filter.

The sponge filter can also be used as a pre-filter on some type of a motorized filter like a hang-on-the-back. With this method of using the sponge, water is still drawn into the sponge via the HOB filter.
The big difference between the two is flow rate and how the water tension around the filter is affected. The sponge being used as a pre-filter, will have more flow than a sponge ran by a air pump. Some filters need these sponge pre-filter to operate properly, so a sponge is a great option.
Also, because the flow is greater, a different design of a sponge is needed. A sponge with larger pores is recommend. Look for sponge filter advertised as a pre-filter.

Sponge filter design has a big impact on flow and versatility, such as the modular design first patented by Lustar then sold to ATI and now used for the AAP/ATI Hydro Sponge.
As well and even more important is the sponge material itself. Long time aquarium professional Carl Strohmeyer performed tests years back and found a profound difference in the capacity of most sponge materials. Even more recent tests involving how many times a sponge has to be rinsed before it runs clear have confirm this.
He found that there also is not a “one type fits all” as with many scenarios, such as smaller fish or lower bio loads, the fine [regular] sponge is the better choice. As well he found better yet results with combo sponge filters utilizing both types or two or more sponge filters with at least one of each type.

By far the clear winner is the patented USA made AAP Hydro Sponge Filter, which means this filter can accumulate much more debris in mechanical filtration and has a much higher bio load than ANY OTHER Sponge filter on the market, well worth the couple more dollars these still 100% American Made filters will cost over the imports [mostly from China under many brands] commonly sold via discounters such as Amazon & Aquarium Co-Op.
In fact beware of the many videos that are simply paid to promote these Chinese made Sponge filters that are infringing on the USA patent design that will claim theirs are better which simply is not true.
A red flag is when the video states that a coarse sponge is better than a regular sponge. This should tell the viewer to “run for the hills” as this shows a lack of knowledge in that as noted earlier there are many situations the regular sponge material is better and often best is one of each or a Combo Sponge Filter (such as sold by AAP).
The bottom line is why purchase a Chinese made patent infringing product when you can purchase a USA made product that is better for only a few dollars more?

The AAP Hydro Sponge Filter generally beats out the still excellent Swiss Tropical sponge filter popularized by a popular YouTuber which with their square design and basic design of intake are less efficient than the AAP/ATI Hydro Sponge Filter [Swiss Tropical definitely excel over the Chinese knock offs flooding the market as per sponge material quality, but their design is simply less efficient].

The AAP Hydro Sponge has more sizes as well as Combo Filters, Pre-Filters, & Central System/Pond Sponge Filters that no other manufacturer/seller have. With the many patent infringing sellers and articles/videos promoting these inferior sponge filters, it is easy to get lost in this sea of internet misinformation. However if still looking for the best and if you value American made products over inferior products from elsewhere, you should not look any further than an AAP Hydro Sponge Filter!!

Each AAP Hydro Sponge and Filter Max sponge filter come in a variety of sizes, based on size of the tank. Make sure to find the size sponge needed for aquarium size and design. Having a larger sponge than what is recommended never hurts also.

Further Reference, recommended reading for those who want more in depth information from a leader in the hobby/industry that has been mentored by many and has mentored many himself: Aquarium, Pond Sponge Filtration | How Sponge Filters Work

Helpful Video:

Pro and Cons of Aquarium Sponge Filters
10 Pro and Cons of Aquarium Sponge Filters

Best for methods

A air pump method of using a sponge filter would be best for:

  • For a hospital aquarium
  • Breeder or fry tank
  • For fish, which prefer a lighter flow such as Discus or betta
  • When simplicity is needed. Best for beginners

A power head method of using a sponge filter would be best for:

  • Higher flow required
  • Less water tension breaking releasing C02
  • Cross currents are wanted
  • For larger fish, which will be more destructive
  • Marine reef applications

Know the recommend flow rate for the type of aquarium being kept. This will determine if a little flow from an air pump is needed or more flow from something like a power head or other filter is required.

sponge filter pre filter, what is a sponge filter, beginner, filter max

A API Filter Max on a HOB

A pre-filter method of using a sponge filter would be best for:

  • When pre-filtration for another filter is required
  • Any risk of small or weaker fish being pulled into an intake
  • No sperate filter is wanted for the aquarium

Please note, there are aquarium sponge filters on the market, which have patented designs. This is due to a ability of being able to collect and hold good micro bacteria better. As well the better patented sponge filters sponge and flow design allows for better water movement within the sponge filter and a higher capacity of mechanical debris filtration.
This where differences will be seen in price and design.

The best of the best are the patented AAP Hydro Sponge Filters, sold via authorized sellers such as American Aquarium Products.

Our Recommended Product Resources:
#Hydro Sponge Aquarium Filters from AAP
#Filter Max Sponge Aquarium Pre-Filters from AAP
#Hydro Pond/Sump Filters from AAP


What are the pros and cons?

fish babies, sponge filter uses

Babies love sponge filters too!

  • A sponge filter can be considered a better filter for some aquarium types, because they strip away less Co2. This Co2 could be needed for a planted aquarium.
  • Sponge filters have a very gentle flow, which is needed for tanks that contain species like shrimp.
  • A sponge will prevent small animals to be sucked into a filter intake.
  • Best choice for aquarium bowl. This is due to bio capacity, low flow, and safeness.
  • A excellent snack for shrimp, crabs, and some fish.
  • Fish love to hide fry on sponge filter
  • One of the only ways a sponge filter can fall short is chemical filtration. The sponge will not allow for chemical upgrades if needed.
  • Another con could be appearance. Some people don’t like the look of a sponge in an aquarium.

Seeding Aquarium- Another major advantage.

carbs, shrimp, sponge filter

Scavengers love sponges

Another major advantage of a sponge filter, which deserves it’s own section, is the ability to use a sponge from an established to cycle a new aquariums. A used sponge can be placed in a higher flow area of a new tank to speed up the process of cycling a new tank. With this method and the use of cycle aids, a new tank can be fully cycled in a matter of days.

A new sponge can also be place right next to another sponge filter or in the substrate of the aquarium, which will seed it very quickly. This is excellent option if another sponge is needed quickly, for something like hospital tank.



Make sure to have regular maintenance of sponge filters. Because of this large bio-load they can hold, they can become Nitrate factories.
During weekly maintenance of the aquarium, rinse the sponge in de-chlorine water and squeeze it out. It’s best to have more than one filter in the aquarium, so you can rinse one, one week and the other the next. Cleaning any filters, this should be in mind. Only clean one filter at a time. After a few months of use from the sponge, replace it with a new one.


As far as filters go, the sponge filter should be in every aquariums keepers tank. The sponge filter could either be the primary form of filtration, or it could be an excellent choice as a secondary form of filtration. Redundancy is very recommend for aquarium filtration. An sponge filter is an awesome way to have Redundancy. Also, consider a sponge filter for the multiple uses it does have. All scavengers love the sponge filter. Because of it’s bio-capacity of the sponge, this form of filter out perform most the rest.

#Red Pest, Invented Fish Disease, Actually Septicemia
#Unique AAP Wonder Shells for Aquarium Mineral Cations
#Premium UV Bulbs/Lamps; for Aquarium or Pond
#Premium Aquarium Silicone Sealant


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