The cleanliness of your aquarium water relies on a functioning water filtration system. But there are so many of different brands and types how do you know which one is the best for your fish friends? Before you set up your aquarium, you should learn the basic concepts of maintaining clean water in your fish tank with the help of aquarium filters. We will explain the stages of filtration, and familiarize you with the most common aquarium filter types.
Table of Contents
- What type of filtration is most important in aquariums?
- What types of fish tank filter are there?
- How to choose the right filter for your aquarium?
What type of filtration is most important in aquariums?
Most people understand that the purpose of filtration is to the removal of waste products in the water. Yes, fish waste can cause problems if left to accumulate. However, filtering is more than just that and consists of three steps.
- Mechanical filtration removes solid and dissolved particles from the water. Things like fish poop and uneaten food.
- Biological filtration converts fish waste products into plant nutrients with the help of microorganisms.
- Chemical filtration removes other wastes and contaminants that could not be removed in the previous two steps. This is done most commonly with the help of activated carbon.
Most aquarium filter types provide all three of those steps. But which type is the best choice for your particular needs?
What types of fish tank filter are there?
Below is a list of the four most common aquarium filter systems. If you are just starting with an aquarium hobby, you’ll find one of these types will work best for your particular aquarium.
- Internal submersible filters aquarium filters are suitable for aquariums up to 50 gallons (200 liters) and are the easiest to use. If you have a small fish tank, we recommend you to go for this type of filtration. This filter type is easy to install, is a standalone device, and is attached to the inside wall of your aquarium. It pushes water through its sponge filter type filter media. When first installed and started up, it only provides mechanical filtration. However, once bacteria start to grow on the filtration media, it also provides biological filtration. Most of these types of filters have two to three filter media pads that can be taken out, rinsed, or replaced when needed. Some filters have an option to put in a filter media that contains activated carbon which also provides chemical filtration.
- External canister filters are installed outside of the fish tank. They take in and then return the tank water to the aquarium through the attached hoses. Obviously such filters require a bit more of an involved setup. They also usually cost more than the above internal filters. The added benefits however, are that they can be cleaned without putting your hands in the fish tank and their filter media can be customized. This is highly beneficial to your fish in that you don’t disturb them when doing filter maintenance. A canister filter usually contains several slots for different types of filter media. Unlike internal filters, a canister filter can provide several different mechanical filtration stages (coarse, medium and fine), one after the other. This fact makes it more efficient and prevents clogging. This means your interval to do regular maintenance on a canister filter is longer. You can also add a filter media specific for your aquariums needs. For example, some fish species require slightly acidic (pH < 7) water. In such case, you can insert a media containing peat which acidifies the water as it passes through the filter media. The same holds true for other parameters that cannot be bought out of the box. If you test and find that your water is rich in phosphorus (a common cause of extensive algae growth), add media to reduce that.
- HOB Filter or Clip-on power filters are similar to external ones. HOB stands for “Hang On Back”. The main and only difference is that they are attached to the side of the tank and sit slightly above it. There are no hoses to attach so installation is much easier than say a canister filter. You’ll want to look at the size of tank you have as not all fish tanks have enough space for them. This is especially true if you already have a hood on top of your fish tank. It is a common choice for many out of the box starter kits for beginners since the hood and everything else is already made to accomodate the specific filter included in the kit. One thing to remember is that if the filter breaks at some point, you will need to replace it with the exact same filter model or replace the fish tank’s hood.
- Underground Gravel filters uses the gravel as their filter material. These filters need to be installed during the setup of an aquarium because a large plate is installed beneath the gravel or underlayment material. A large surface area means improved biological filtration. Biological material trapped in the gravel also means more nutrients for the plants. There is also an added benefit that the filter is not visible. There are tubes that run along a back wall and corner, but they can be made to produce bubbles which helps in aeration making them valuable to your fish and add some beauty to your tank. It may be a bit more work to set up a gravel filter, but when done right they work really well.
There are other aquarium filter systems available, though not as common. Most beginners are best served with internal or clip on filters. If you come across a system not mentioned here, do not hesitate to ask the salesperson at your local aquarium store to explain how it works and seek information on the manufacturer’s website.
How to choose the right filter for your aquarium?
The first thing you need to pick the best aquarium filter for your tank is the size. How many gallons (or liters) of water your aquarium holds. Do you have a large tank or a smaller tank? One question many ask is does a small aquarium need a filter? The second is, does a large aquarium need a filter? The answer to both question is that an aquarium is a closed system. That system is not self cleaning. The fish produce waste products that collect and will eventually lead to a poor living environment for your fish. This all means that every aquarium needs filtration.
The size of your fish tank is the key because it will help you select the correct water flow rate of the fish filter. Granted, many of us had a goldfish in a bowl as kids. All the goldfish had in the bowl with them was the water. The way we kept the fish happy is through a water change. And of course, those goldfish didn’t last very long.
The features of each different type of filtration system discussed above discuss some of the positives and negatives of each type. For example, undergravel filters means that to clean it, you have to vacuum the gravel to remove the build up of organic material. A canister filter system while more convenient to maintain as the filter media is easily accessible. The downside of even the best canister filter is removing and either cleaning or replacing the filter media or filter cartridge can be quite involved. Even the best fish tank filter needs to be maintained on a regular basis to keep the water in your aquarium as clean as possible.
Why not just do a water change? Well, most tap water contains chlorine which is very harmful to your fish. If you leave the tap water in your aquarium without fish or plants for some time, the chlorine will dissipate. The amount of time will depend on the amount of chlorine in your tap water. Make sure you let at least 24 hours to pass and you may have to wait several days. During that time, you either have to have a large container to let the water rest before changing your tank water. Then you have to have a place to put your fish while you are changing the water. Oh and don’t forget to test the water with a kit you can get from your fish store.
So “just changing the water” instead of putting in a filter is much harder than it sounds. Especially because you’d have to do it quite often if you have a lot of fish. It’s just not practical.
Note that whatever power filter system you choose, they all rely heavily on beneficial bacteria that provide a biological breakdown of waste products. This means that whenever you set up an aquarium, you should run it for several days before adding fish so that the bacteria has time to multiply and colonize inside of the filter media.
Back to the question this article is about, what are the best fish filters? Now you understand the different types and the pros and cons of each, you can select the best filter for your aquarium and lifestyle. This will go a long way towards a happy life for you and your pet fish. And keeping your Pet Happy is what we all want.