Aquariums are a wonderfully traditional way for fish to have an outdoor home, but they are also a very popular method of keeping live plants inside. As such, you will need to provide your aquarium with sufficient filtration so that all the waste and chemicals it removes from the water are recycled properly. Without good filtration methods, you may experience water quality issues in your tank, along with toxic algal blooms which will cause harm to your fish and the plants they live in. You will also need a filter if you plan to have livestock in your tank, as smaller fish will be harmed if they are not able to live in clean water. While there are many different kinds of filtration systems for aquariums, the following seven are the best aquarium filters.
1. Canister Filters
Many people prefer to use canister filters that sit on the floor of your tank because they’re more efficient than hang-on filters and are less fragile to handle. Canister filters place several small filter cartridges inside a single unit, in which waste particles are trapped and removed from the aquarium water. These filters are especially good for large tanks because they provide better oxygenation and filtration than simple hang-on filters. An example of a good canister filter is the Fluval Spec III Canister Filter.
2. Undergravel Filtration
This type of aquarium filter requires a special substrate (a sand-like layer that sits at the bottom of the tank) to be used as a “filter.” It is used in large tanks that house plenty of fish. Undergravel filtration uses tubing, usually made out of plastic or PVC, that runs underneath the gravel. As water flows through the tube, waste particles are sucked in and trapped in small pockets within it.
This is a beneficial filter because it allows even more oxygenation than other filters do. The downside? It is very difficult to set up and maintain. An example of an under-gravel filter is the Eheim 2213 Undergravel Aquarium Filter.
3. Hang-On-Back (HOB) Filters
These are among the best aquarium filters on the market because of their size and design. The water essentially circulates through the filter cartridge, which is attached to a plastic hose. It’s not as simple as a sponge filter or canister filter; it’s more like a power filter. The water must flow over different surfaces across the “hose” that holds in and returns out the water. This means that if there are air pockets in the hose, then oxygen will be knocked out, causing your water to go bad and your fish to die.
4. Internal and Submersible Filters
Smaller aquariums, such as bowls and vases, use a type of filter known as an internal or submersible filter. These filters are generally very small and sit inside the tank itself. They are also very easy to maintain, and usually only need to be cleaned once a month. But these filters aren’t just for smaller tanks; they’re also for larger tanks that house much fish because they provide low levels of filtration enough to keep your tank clean but not enough to disturb the delicate ecosystem living in it. An example of this type of filter is the Marineland BioWheel Aquarium Power Filter.
5. Sponge Filters
Sponge filters are also small and easy to maintain, but they have different mechanization than an internal filter. Instead of a physical or mechanical filter, a sponge will remain stationary in the tank and trap particles in its tiny pores. The advantage to this type of filter is that they can be set up in larger aquariums because they are less sensitive to the flow direction and pressure than other types of filters. They’re also easier to clean because you only need to remove the sponge when it needs to be cleaned.
6. Wet/Dry Filter
Another option for a fish tank filter is the wet/dry filter. Though they are not as common as other filters. They are used by experienced tank owners. The filters are great for biological filtration because the media is exposed to water and air. However wet/dry filters are cumbersome to install and maintain. The filters also require a lot of maintenance to keep them running properly.
7. Fluidized Bed Filter
A fluidized bed filter consists of a large tank that is filled with lots of media (usually, gravel or sand), which water pumps through. It uses a column of water that is forced to flow quickly through the tank, creating a lot of turbulence. As water flows through the tank, waste particles are trapped in the media. This is a good filter for tanks that have lots of waste or decalcifying fish, but it is also very large and requires a lot of maintenance (at least weekly siphoning). It can also back up water in the tank if the media is not changed regularly. An example of a fluidized bed filter is the Deltec fluidized bed filter FR 616
Just like anything else in this world, there are benefits and drawbacks to each type of aquarium filtration system available today. You should choose a filter that will fit well with your tank, and one that you can afford to properly maintain.