Hands down, the most important thing that you need for your aquarium is a good filtration system. Whether you have fresh or saltwater, proper filtration is an absolute must. There are so many types of filters available, however, that picking the right one for your desired set up can be a daunting challenge. This article will take the guesswork out of the different stages of filtration (mechanical, chemical, and biological), as well as help you figure out which kind of filter is best for your aquarium and experience level (wet/dry, canister, and hang-on filters).
There are three basic stages of filtration. The first stage is generally going to be some kind of mechanical filtration. This is the most basic form of filtration, and what most people would think of as a true filter. For example, the paper liners that you use in a coffee machine use mechanical filtration to separate the coffee grinds out of the actual coffee. Mechanical filtration basically just means that some sort of material, known as filter media, is used to separate particulate matter from the water. Mechanical filtration usually comes in the form of foam or cotton pads, and it is very important to keep your mechanical filtration media clean so as to prevent a build up of debris.
The second stage of filtration is chemical. Chemical filtration is useful because it chemically binds to itself substances that are too small for mechanical filtration to get rid of. Carbon is the most commonly used form of chemical filtration. Due to the high temperatures and pressure used to create carbon, it becomes extremely porous at the molecular level. Carbon is then able to attract microscopic substances out of the water and into the micropores in a process known as adsorption. Chemical filtration is generally most useful in marine reef systems.
The final stage of filtration is biological, and this is by far the most important type of filtration. Proper biological filtration is what is going to keep your tank from spiking ammonia and nitrite, and is also going to have the most integral hand in keeping your fish happy and healthy. Biological filtration basically means that there are colonies of beneficial bacteria living in and on your filter media, feeding on nitrogenous wastes that build up in your tank. These beneficial bacteria are what you allow to colonize while you are waiting for you tank to cycle (read more about cycling here). This microscopic critters need three things to survive; food, oxygen, and plenty of room to grow. You won’t need to feed them, because, as mentioned earlier, these bacteria feed off the wastes that are already present in your aquarium water. They will need plenty of oxygen, however, in order to thrive.
Now that you have a basic understand of the three stages of filtration, it’s time to get into the different kinds of filters are available. This article will be focusing on the three main types of filters – hang on, wet/dry, and canister.
Hang-on filters are probably the most readily available and the easiest to use. Perfect for beginners, these filters are pretty much self-explanatory in that they literally hang off the side of your aquarium. Most hang-on filters come with a mesh pouch containing carbon (or some other form of chemical filtration) as well as a separate biological medium, such as corrugated, high surface-area plastic. Although these particular filters are easiest for beginners due to their simplistic design and ease of use, we would caution that because they are so compact you probably would not be able to fit in all the various forms of filtration media that you might need. We recommend the Aqua Clear hang-on filter, manufactured by Hagan. Aqua Clears compartmentalize the filter media, allowing for easier cleaning and versatility in available filter media.
Canister filters are more popular amongst intermediate hobbyists and are most often used on saltwater aquariums and planted tanks. Canister filters, such as the Eheim series, are all-inclusive; everything that you need comes in the box, taking the guesswork out of figuring out which types of filter media you would need. They allow for a greater quantity and variety of filter media. Another plus for canister filters is that they are closed systems, making them less likely to overflow when properly sealed. Canisters, unlike hang-on filters, are also external. They are able to sit inside cabinetry, hidden from view, making for a more streamlined and aesthetically pleasing aquarium. Canisters are also able to be disconnected for cleaning without disturbing the tank. Although cleaning a canister is a little more involved than hang-ons or wet/dry filters, canisters only really need to be cleaned approximately once a month.
Finally, we come to wet/dry filters. Wet/drys are the least utilized but most versatile filters available in the hobby today, and are recommended for intermediate and advanced hobbyists. They are also highly recommended for anyone who maintains a reef tank. Also known as a trickle filter, wet/drys allow for the water to pass through some form of mechanical filtration, and then that oxygenated water streams over a form of high-surface area biological substrate. Wet/dry filters have the highest level of biological filtration, thereby increasing your tank’s capacity for livestock. Because they have to be set up inside the cabinetry beneath the tank and plumbed back to the tank for return, wet/dry filters tend to turn away fishkeepers. However, once they are set up and running, wet/dry filters are the easiest to clean and maintain. We recommend the ProFlex wet/dry filter for its versatility.
Now, you should have a basic understanding of not only the stages of filtration that are necessary to maintain a happy and healthy aquarium, but also a general knowledge of the types of filters available. As always, if you have any questions regarding filtration or any other aspect of the fishkeeping hobby, feel free to give us a call at the store. You can also find us on Facebook and Twitter. Good luck!
