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Anyone with an aquarium wants to create an environment that allows the fish to live in it to thrive. Filters play an important role in this. However, with so many options on the market like sponge and canister filters, how can you guarantee you’ve picked the right filter for your aquarium?
A sponge filter is a great option for aquariums with small or slow swimming fish and smaller tanks, as well as for anyone with a smaller budget. On the other hand, canister filters are best for large tanks with lots of aquatic animals or aquariums with fish that need particular, stable environments.
This article will further explore the differences between these two filters, covering how they work and their pros and cons, and provide helpful factors to consider when deciding on a filter for your aquarium.
Sponge Filters: A Basic Overview
If you’re looking for the right filter for your aquarium, you likely know what purpose these filters serve and how crucial they are in maintaining a healthy aquarium. With so many options to choose from, however, it can seem a little overwhelming at times. Sponge filters are actually a great place for beginners to start. Let’s take a closer look at how this filter option works, as well as its benefits and drawbacks.
How Do They Work?
All filters work to clean the aquarium environment by moving water through whatever is inside of them. While there are three main types of filtration methods, sponge filters use something called mechanical filtration. This means that the sponge physically catches contaminants passing through the water instead of using chemicals like activated charcoal to neutralize odors or harmful chemicals.
Sponge filters are placed right over a water pump’s intake. Even though this makes the installation process relatively simple, even the most basic sponge filters aren’t just a sponge. Most filters come with four distinct elements, these parts as:
- The sponge
- A weighted base to stop the light sponge from floating around the aquarium
- A strainer, slid directly into the center of the sponge to allow the tubing to connect directly to the filter
- A lift tube, which moves water through the tank
Once it’s been placed into the tank, sponge filters get to work via a simple but incredibly effective process. As water circulated by the air pump is forced through the sponge, the material of the sponge traps anything contaminating the water.
This includes fish waste, large clumps of decaying plants, uneaten food, and anything else that may have fallen into the tank. With these contaminants now removed, the water that exits the sponge is now clean and can recirculate.
Even though this process is very simple, it’s incredibly effective. Sponge filters have been around for a long time for a reason. Since it’s an older method, some people assume that newer filters will offer better results – especially since stores don’t promote sponge filters a lot.
This is often because they’re cheaper, so stores push products that will make them more money. In fact, the tanks in most aquarium supply stores are likely to use sponge filters.
Pros of Sponge Filters
As I previously mentioned, sponge filters are very effective. While this is obviously extremely important, there are more factors than efficacy to consider when deciding which sort of filter is right for your aquarium. Luckily, sponge filters offer a ton of additional benefits. Some of sponge filters’ many benefits include:
Perhaps the best reason to purchase a sponge filter is how cheap they are. As outlined above, these filters are composed of only a few components, so they don’t cost much to make. Using a sponge filter will also save you money in replacement parts, as there is no need to repurchase charcoal media or other electric accessories constantly.
Can Work With Other Filters
Sponge filters are sometimes called pre-filters because they work well with additional electric filters. Especially for large tanks, sponge filters can offer a good source of mechanical filtration while another filter handles chemical filtration. Over time, bacteria growth on sponge filters can also provide biological filtration. Having multiple sources of filtration will guarantee a clean tank.
Offer Gentle Filtration
Some aquatic animals cannot handle the strong current that some filtration systems produce. Betta fish, for example, are slow swimmers that could be injured in a strong current. Small aquatic organisms, like brine shrimp, actually run the risk of being sucked into the filter. Sponge filters prevent this from happening by offering a gentle current that even the most delicate aquatic animal can thrive in.
Offer Biological Filtration
In addition to the mechanical filtration of physically catching contaminants, sponge filters also offer biological filtration. Over time, sponge filters will begin to grow the natural bacteria that help aquariums break down waste. You don’t need to take any extra steps for this to happen, so it’s like getting two filtration systems for the price and maintenance of one.
Some types of filters can be incredibly loud, especially those with rubber seals that offer extensive surface agitation. Since many people have aquariums in their homes and businesses to create a peaceful environment, a loud filter may defeat the purpose. Sponge filters, however, are very quiet. It’s possible not to notice the sound, although some have said that it sounds like a small waterfall. This, in itself, maybe relaxing.
Easy to Clean
Cleaning a sponge filter could not be easier. Simply remove the sponge and rinse off with some water from the weekly water change. It’s important to not clean the sponge too much, as the good bacteria that grows aids in biological filtration. Therefore, you don’t have to worry about cleaning thoroughly. It should take under five minutes for the entire process.
Cons of Sponge Filters
While there are a lot of benefits to using sponge filters, there are accompanying negative aspects. It’s important to weigh these drawbacks against the benefits before deciding on your filtration method. Some of these cons include:
Not Aesthetically Pleasing
Many people that do not use sponge filters cite their appearance as what holds them back from purchasing one. As opposed to filters that hang over the back of the tank, sponge filters go directly into the tank, making them visible. A bulky black sponge might not go with the colorful theme you’ve cultivated in your aquarium. Carefully arranging plants and other accessories in the tank may be enough to hide it, however.
Use Less Filtration Media
While sponge filters are effective, it is undeniable that they are smaller and use fewer filtration media than other filters. If you have a very large tank or are nervous that a sponge may not be enough to filter that much water, consider using a sponge filter as a pre-filter in addition to another system.
Don’t Offer Chemical Filtration
There is quite a bit of controversy surrounding whether or not an aquarium actually needs chemical filtration. According to Duke University, aquariums must have biological filtration but do not require chemical filtration like activated carbon. If you disagree, however, sponge filters may not be the best option for you.
May Tempt Fish
As mentioned earlier, sponge filters can catch uneaten food. While this is great for cleaning, it also means that a fish or turtle may swim up to the sponge and try to take a bite of it. Eating sponges, of course, isn’t great for any aquatic animal. If you keep your tank well-fed, however, you should be able to avoid any unnecessary sponge consumption.
Canister Filters: A Basic Overview
While sponge filters are a great option for many aquariums, people that have been keeping aquariums for a long time may eventually want to upgrade to a more sophisticated system. Canister filters are a great option for anyone looking to grow their aquarium or control different elements of the aquatic environment. Keep reading for more information on how the “workhorse” of filters actually works.
How Do They Work?
Canister filters are typically placed outside of the tank itself, usually underneath or behind the aquarium. Fittings are placed in the tank and then connected to vinyl tubes that run to and from the filter, allowing water to be transported back and forth. Once water enters the canister filter, it passes through multiple trays of filter media (usually activated charcoal) to clean the water of debris, waste, and other contaminants via chemical filtration.
However, canister filters are considered an upgrade because of the mechanics that allow chemical filtration to happen. Internal motors or in-tank pumps work to push water into the filter. When the filter is full, an internal pump then pushes the water out of the filter, through the tubes, and back into the tank. This process allows for a large amount of water to be filtered both quickly and easily.
While you have the choice of canister filters with an internal motor or in-tank pump, experts recommend going with an internal motor. The internal motors are easy to clean and maintain, as you don’t have to reach into the tank and touch a dirty pump. In-tank pumps also take up space in the tank and can be an eyesore, while canister filters with internal motors can be hidden outside the tank.
Pros of Canister Filters
You’ll find canister filters in the tanks of many intermediate and experienced aquarium enthusiasts. These pros are even willing to pay over $100 for these inconspicuous, versatile filters. So what exactly makes them worth the money?
Offer Excellent Filtration
Most importantly, canister filters offer superior filtration. Their powerful motors and filter media capacity offer a level of filtration that simpler filters cannot provide. This makes them ideal for aquariums with heavy bioloads, which FishLab explains as all the waste inside your tank from fish waste, decaying plants, and even gases expelled by the fish. If your aquarium has a lot of fish or gets dirty easily, this may be the filter for you.
This Marineland Magniflow Canister Filter from Amazon.com uses black diamond carbon to provide exceptional filtration and is available in 30, 55, and 100-gallon sizes.
Don’t Affect the Look of Your Aquarium
As previously mentioned, canister filters do not sit in the tank itself. This is convenient, as most canister filters are somewhat big and bulky. Not only does having the filter located outside the tank allow for a more cohesively and thoughtfully designed aquarium, but it also frees up a lot of space. The filter can easily be obscured outside the tank by placing a plant or other decorative accessory in front of it.
You can buy canister filters with lots of extra add-ons or modify an existing one yourself. Some of the most popular additions are UV sterilizers and water heaters/chillers. These allow for modifications to the aquarium environment that make it possible to add in different aquatic animals that require very specific living conditions.
Like sponge filters, canister filters are extremely quiet. In fact, many would argue that they are even quieter than sponge filters. Even with an internal motor, canister filters have become quieter as time goes on. The motor is contained within the filter, offering insulation, and any sounds you do hear will be smooth and consistent. Most canister filters on the market have been designed to operate very quietly.
Good for Sensitive Fish
Some fish require pristine water conditions with very specific, stable conditions. Since canister filters can be easily customized to control different environmental factors like UV sterilization and water temperature, even the most delicate fish or invertebrates can survive in these tanks. The intense cleaning process of canister filters ensures that harmful pollutants will not harm these animals.
Good for Large Tanks
Another reason that canister filters are so popular with advanced aquarium hobbyists is their ability to filter large tanks. Canister filters work great for tanks over ten gallons but have been known to work successfully on up to 400-gallon tanks. They also work equally as well with both salt and freshwater tanks. If you’re looking to create an impressive aquarium full of lots of different animals, the power of a canister filter is for you.
Cons of Canister Filters
Just as with sponge filters, the pros of canister filters must be weighed against their cons. Before investing in a canister filter for your aquarium, here are some drawbacks to keep in mind.
Can Be Expensive
Canister filters are more expensive than most other types of filters. However, this accompanies their high efficiency and more sophisticated design, so you are definitely paying for quality. While this price tag may be worth it for experienced aquarium enthusiasts, beginners may want to start with a more affordable filter while still learning.
Difficult to Clean and Maintain
Cleaning or performing any regular maintenance on a canister filter can be difficult. To clean the inside of the filter, you’ll need to disassemble the entire setup essentially. There’s also a greater chance of flooding during servicing, so you may get a little wet. While a little extra work shouldn’t deter you from using this filter, make sure you’re willing to set aside some extra time before making a purchase.
Need the Power to Operate
Since canister filters require power to run their internal motors, a power outage will stop this process. If the pump stops, water flow to the filter will also stop. Without the water flow, the tank will lose oxygen, and good bacteria dependent on it for growth will die. While a sponge filter sits inside the tank, canister filters are located outside the tank, so bacteria have a higher chance of suffocating in the small, enclosed space.
How to Choose a Filter?
Hopefully, reading through the pros and cons of both sponge and canister filters has given you a better idea of which option will be best for you. Before making any purchase, you need to decide exactly what you want your aquarium to look like and what you’re looking to get out of it. It can also help to ask yourself these two important questions:
What Type of Aquatic Life Will My Aquarium Contain?
The entire purpose of an aquarium is to provide a good living environment for the plants and animals inside it. Filters can help to create this environment. The aquatic animals you choose to put into your aquarium play a huge role in choosing a filter. Are these animals slow swimmers or especially tiny? Are they delicate and need special modifications to the water temperature? Use this to guide your decision.
It’s also crucial to know how many aquatic animals you’d like to have in your tank. You’ll want to think about whether you plan to expand later, as well. For example, if you plan to have breeding fish in your tank, you should choose a sponge filter. Take the time to do the research to see what environment is best for the animals you’re looking to keep.
How Much Money and Time Am I Willing to Spend?
Everyone has a different budget for their aquarium. If you’ve only just begun or are looking to have only one or two fish, it doesn’t make sense to splurge on an expensive filter. At the same time, however, you’ll be able to spend less time cleaning and maintaining it. If you’re looking to invest in a pricey filter, you must be willing to commit to the maintenance that comes along with it. Regardless of what filter you get, you must take care of it for it to operate properly.
Both sponge and canister filters are incredibly effective. Which filter you choose to go with depends on your budget and the time willing to dedicate to maintenance. As well as the look you’re going for with your aquarium and the animals you want to live in it. As long as you know what sort of aquarium you’re trying to build before you start making purchases, you should be able to find the perfect filter.