Having a filter is important in your fish tank as it will keep your water clean and provide a healthy environment for your pet fish.
This guide at Aquarium Blueprints will help you find the fish tank filter best suited for your aquarium.
Quick Navigation:
- Filtration Types
- Box And Corner Filters
- Canister Filters
- Hang On Back And Power Filters
- Moving Bed Filters
- Sponge Filters
- Undergravel Filters
- DIY and Sump Filters
Aquarium Filtration Types
Before we begin, let’s talk a little bit out the filtration types that most filters offer.
The first and most important is biological filtration. This is essentially living bacteria that helps break down wastes in your aquarium. The fish food and fish poop in your tank will turn into ammonia. The biological filtration will convert ammonia to nitrite and then nitrite to nitrate. These beneficial bacteria actually grows on all surfaces if your fish tank in addition to your filter.
The next filtration type is mechanical, which are meant to keep your tank looking clean and water looking clear. This is done by trapping small particles (such as fish food, fish poop and other types of debris) on a sponge of floss. This type also makes it more convenient to remove the wastes from your water as all the particles are trapped into one place.
The final filtration type is chemical. This will help you remove certain elements from the water such as medication, nitrate and tannins. Most fish keepers use activated carbon for chemical filtration as well as nitrate removers.
As we already stated above, you should worry about biological filtration the most, followed by mechanical filtration. In our opinion, chemical filtration can be ignored aside from specific situations such as if you have to remove medicine from your tank and/or looking for a fast way to reduce the nitrate levels.
It is possible to set up a fish tank without a filter. If you are interested in doing so, you can take a look at this article.
Box and Corner Filters
The oldest form of aquarium filters is the box filter, which is also known as the corner filter. Using an air pump, water is sucked into a container that houses sponges as well as other media types. The best selling points for box filters is that they are affordable (if you already have an air pump) and customizable with different filter media.
With that said, they aren’t particularly effective in larger tanks of at least 55 gallons due to the lack of water flow. In that case, you might want to consider using multiple box filters in the same tank.
Box and Corner Filter Pros:
- Affordable
- Customizable with different filter media
Box and Corner Filter Cons:
- Lack of water flow
Canister Filters
Canister filters usually use an internal water pump to move water from your fish tank into a container that has sponges and other filtration media types. The water is then pumped back into the aquarium. While expensive, canister filters are great for bigger aquariums as you can direct the water flow (we recommend putting the intake on one side and the outtake on the opposite end to maximize the movement in order to create more efficient filtration). Because the filter media is all included in an external canister, you only need a minimal amount of space in your tank.
The biggest drawback is having to clean the canister filter. Because it is seal air tight to prevent any water from leaking, these filters are typically hard to open. Not to mention that there is a good chance that water will be spilling out. So you will want to clean the canister filer either in your sink, bathtub, showers or outside near a drain. A lot of canister filters also need to be primed in order to add water and get it working as well. This process takes quite a few pumps.
New fish keepers should also be attentive when it comes to canister filters. This is because this type promotes “out of sight, out of mind” mentality. Just because you don’t see any build up of detritus in your fish tank, doesn’t mean that you don’t have to clean your canister filter and do a water change.
While it requires more upkeep when compared to other filters, we still highly recommend getting a canister filter if you have a fish tank of at least 55 gallons (and up to 250 Gallons) as you can direct the water flow, making filtration more efficient. We recently posted a comparison between the Fluval 06 and 07 Canisters, which you can check out with this article.
Canister Filters Pros:
- Takes up minimal space in the tank
- Can direct water flow
- Customizable with different filter media
Canister Filters Cons:
- A little on the expensive size
- Hard to clean
- Could lead to “out of sight, out of mind” mentality
Hang On Back and Power Filters
The hang on back filters, also known as power filters, are designed to put on the back of your fish tank. Using an internal pump, it sucks up the water to the filtration media. Water is then returned to the aquarium through gravity, which creates an aesthetically pleasing waterfall effect. Not to mention that, if you have an open top, you can grow aquaponics plants such as Lucky Bamboo and Pothos, on it.
When compared to the canister types, hang on back filters are easier to clean. With that said, it pales in comparison when it comes to water flow as you can’t dictate the direction where water is outputted. In general, canister filters also provide more space for filter media when compared to hang on back filters.
Although not as powerful or efficient as canister filters, hang on back filters are still perfectly capable of filtering tank sizes of up to 70 gallons. If you care about how your aquarium set-up looks, then this type will add a lot to the aesthetics of your tank.
Hang On Back and Power Filters Pros:
- Aesthetically pleasing
- Customizable with different filter media
- Can grow aquaponics plants with an open top
- Easy to clean when compared to canister filters
Hang On Back and Power Filters Cons:
- Takes up space on the back of fish tank
- Does not offer the same amount of space for filter medias as canister filter
- Not able to direct water flow
Note: You can take a look at our comparison guide between the MarineLand Penguin and MarineLand Penguin Pro in this article.
Moving Bed Filters
Moving bed filters used an air pump to move water through filter media. The current is strong enough that the media will be constantly moving. Because the filter media is constantly hitting against each other, moving bed filters ensure that only the strongest beneficial bacteria survive. Having moving filter media can also be aesthetically pleasing to look at.
The only issue we have against moving bed filters is that they aren’t great for mechanical filtration, especially when compared to the amount of space they take up in your fish tank (aquariums of up to 40 gallons should be fine, however). Not to mention that this type don’t really move the water as well as other types.
Therefore, we recommend bed filters only as a secondary filter to complement your primary filter in your fish tank.
Moving Bed Filters Pros:
- Stronger bacteria growth
- Can be aesthetically pleasing
Moving Bed Filters Cons:
- Takes up a lot of space
- Not great for mechanical filtration and water flow
Sponge Filters
Sponge filters are simple but very effective. They used an air pump in order to suck up detritus via a giant sponge, which also provides surface area for beneficial bacteria to grow. The best aspects for this type of filtration are that the sponges are more affordable and easier to clean when compared to boxes, canisters and hang on backs. There’s a reason why fish keepers with multiple tanks, as well as fish store owners, use sponge filters for filtration.
There are some notable disadvantages, however. One of which is that you can’t use any other filter media as there are no compartments. Furthermore, it will also take up space in your aquarium and use a weaker flow when compared to canister and hang on back filters. In regards to the weaker flow, you can easily increase the current in your fish tank by using another sponge filter since they are pretty affordable.
Sponge filters are great for small and medium size tanks of up to 40 gallons. Because they are very affordable, you can also use multiples of them for bigger tanks as well.
Sponge Filters Pros:
- Most affordable aquarium filter type
- Easiest to clean
Sponge Filters Cons:
- Takes up space in the fish tank
- Can’t use other filter media
- Don’t have the same water flow as canisters or hang on back filters
Undergravel Filters
The undergravel filtration is an uncommon filtration method. The filters are placed under the gravel, so they don’t take up that much space. It uses either an air pump or power head to suck down detritus into the gravel.
Although undergravel filters work, they can be a pain to clean as you need to remove the substrate first. Not to mention that the filter media can get clogged very easily, especially if you using substrate with small particles such as very fine sand.
Because they are so hard to clean, we recommend looking at other filters in this guide.
Undergravel Filters Pros:
- Takes up very little space
Undergravel Filters Cons:
- Can get clogged very easily
- Have to remove substrate to clean
DIY and Sump Filters
For extremely large tanks of more than 250 gallons, a lot of aquarists make their own filter. These DIY and Sump filters are usually made with another tank that contains a lot of sponges as well as other filter media to encourage beneficial bacterial growth. These filters use a water pump of suck in and spit out water from the fish tank.
The only negative to the custom filters is that they take up a lot of space on the outside of your tank. With that said, if you want a huge aquarium, the most effective filtration method is to build your own.
DIY & Sump Filters Pros:
- Customizable with different filter media
DIY & Sump Filters Cons:
- Need a lot of space
Recap
Sponge filters are affordable but very effective and easy to clean. Thus, we highly recommend using them for aquariums up to 40 gallons.
Canister filters are great when it comes to water flow and providing a lot of surface area. So, while cleaning them can be a pain, we still recommend using canisters for fish tanks between 55 to 250 gallons.
Hang on back filters a nice in-between option between sponge and canister filters, especially if you like having a waterfall and may want to grow some plants (which will help consume ammonia, nitrite and nitrate) on your filter.
For really large tanks (more than 250 gallons), you ware better off trying to build your own filter so that your tank can get the proper filtration.