Aquarium Filtration can be very confusing to new hobbyists. I know whenever I started with my first fish tank I had no clue what type of filter I needed or what the whole biological process was. So, what the heck are the 3 stages of most filters?! I will explain.
The best type of filter to get for your aquarium if you are starting out would be a hang on back (hob) filter. I have used these types of filters for over 10 years and they always keep my aquarium water crystal clear. Some recognizable brands would be AquaClear, Aqueon, and Whisper. I am using an AquaClear 50 on my 20 gallon tank right now.
Filter Media: Mechanical, Chemical, and Biological.
- Mechanical- This is the sponge or foam part of your filter. It sits at the bottom of the filter and removes fish waste. This part of the filter usually gets the dirtiest and must be cleaned every couple of months depending on your fish load.
- Chemical- This is the middle part of your filter and looks like little pieces of coal. The black components are actually active carbon. This is the part of the filtration process that makes your water clear, and reduces odors. The carbon also removes harmful elements such as Copper, Chlorine, and Dissolved Proteins. The carbon bag should be replaced every 3 months to keep your aquarium looking fresh!
- Biological- This is the top part of your filter. It is a white looking bag with little rock type components. This is probably the most important part of aquarium filtration because it is where the “good” bacteria live. Once your aquarium is cycled and your good bacteria is present, they will then consume ammonia and give off nitrite. The nitrite will then turn to nitrate. You do not have to replace the biological part as often, and clean lightly so you do not kill off your beneficial bacteria.
BIGGER Filters: If you have a larger aquarium and messy fish, it may require you to upgrade your filter. Some options would be a canister filter made by Fluval. I had a Fluval 305 on my 55 gallon Piranha Aquarium. The same Filtration process that I explained above takes place inside these canister filters, but on a much grader scale.
Types of External Aquarium Filters:
Canister Filters- Canister aquarium filters offer a better quantity of filter materials to be used along with a the flexibility with filter material choice. Canister filters work by an intake pipe that pumps water out of the aquarium and enters the canister with the filter media inside of it. The water then passes through the bottom of the canister and is filtered through your filter media.The water is then pumped back through an output pipe by and electric motor that returns the clean water back into your aquarium. Benefits of this type of filter are that they can provide a high volume of filter material without reducing the internal space in the aquarium. It is also very easy to clean by disconnecting the pipes from the canister and then you can rinse out the inside, clean filter media, or replace it. This is a very good feature for all types of freshwater and saltwater aquariums so you do not disturb your fish, plants, or corals. Some of the disadvantages of the canister aquarium filter are due to cost. The cost to replace filter media can be a little more expensive then your typical hang on back filter. Also, cleaning the pipes to and from your aquarium can be tedious. All in all the canister filter is an awesome choice for any type of larger aquarium!
Diaton Filters- In the aquarium hobby, Diaton Filters are not used continuously. They are only used occasionally and utilize diatomaceous earth to create an extremely fine filter down to 1 µm which removes microscopic particles from the water column that are harmful to your fish. These filters are rarely used unless your setup in quite large.
Trickle Filters- Trickle aquarium filters are also know as wet/dry filters and are usually placed on top of your fish tank. These can be used in either freshwater or saltwater aquariums. If the wet/dry filter is placed on top of the aquarium, water is pumped over a few perforated trays containing filter media like a sponge or wool. The water trickles through the trays, keeping the filter wool wet but not completely submerged, allowing aerobic bacteria to grow and aiding biological filtration. Then, the water returns to the aquarium like rain. This process is very natural and beneficial to aquarium life.
Baffle Filters- Baffle filters are similar to trickle filters, but are generally situated below the aquarium. This type of aquarium filter consists of a series of baffles that the water must pass through in order to reach the pump which is returning water to the aquarium. These baffles pretty much represent a series of canister filters and can be filled with different filter media for different aquarium processes. Just like mechanical, biological, and chemical like stated above.
Types of Internal Aquarium Filters:
Airlift Filters- Airlift aquarium filters are also known as sponge filters. These are commonly used when hobbyists are breeding fish. They are essentially the same as mechanical filtration but as an internal filter. They work by using bubbles like an air stone through airlift. The rising bubbles in the tube create a flow, and water is sucked through the sponge then trapping debris. These filters can only be used in small aquariums with a small bio load. The Sponge must be cleaned every so often and particles stick to it. The Airlift Filters are also great for aquariums with small fish that you are afraid may get sucked into a traditional hang-on-back filter.
Undergravel Filters- The undergravel aquarium filter has become very popular within the past 5 years. These filters are now pretty common in the typical 10 gallon aquarium. The undergravel filter consists of a plastic plate that sits beneath your gravel at least one uplift tube. Airstones are then placed at the base of the uplift tubes which force water out of the uplift tube creating a negative pressure beneath the undergravel filter plate. Water is then pushed down through the gravel and the gravel then becomes your actual filter media. Beneficial bacteria colonize the gravel bed and provide biological filtration using the substrate of the aquarium as the filter.