Most fish farmers rely on a combination of three different filtration methods to keep the water quality in their aquarium high: mechanical filtration, biological filtration, and chemical filtration. Mechanical filtration will remove larger debris from the water, biological filtration is done by bacteria that convert hazardous waste products into less harmful compounds, and chemical filtration is usually done with activated carbon that will bind toxic compounds, traces of drugs, etc.
Several types of filtration can be carried out in the same equipment. When you look at the basic sponge-filled corner filter used by many novice fish farmers, you may think it’s just a way to do mechanical filtration. However, the truth is that the sponge is an ideal home for beneficial bacteria that can perform biological filtration. The corner filter is usually combined with a pump that generates a flow of water and constantly supplies the bacteria with biological waste products that are dissolved in the water. If you put a piece of activated carbon in your corner filter, it will perform a chemical filtration of the water that is pumped. In this way, you can have three different types of filtration on the same computer.
mechanical filtration
Mechanical filtration will remove larger debris from the water. You can get internal and external mechanical filters. A mechanical filter is usually combined with a pump that forces water through some type of filter media, for example sponge, foam, or dental floss. Before purchasing a mechanical filter, you should always find out how much water it will circulate and how fine the filter media is. A general rule of thumb states that a mechanical filter should pass about twice the amount of water in the tank every hour, but this is not true for all types of aquariums.
The fineness of the filter medium in a mechanic is very important. A very fine filter media will catch even the smallest debris in the water, but on the other hand, it is prone to clogging and needs to be cleaned very often. A coarse filter media is less prone to clogging, but on the other hand it will allow a lot of debris to pass through. Many aquarium keepers use a combination of various filter media, where a coarse filter traps large particles before the water is passed through a finer media.
biological filtration
During biological filtration, the harmful nitrogenous compounds produced by the animals in the aquarium will be converted to less harmful nitrogenous compounds by two different types of bacteria. Your fish’s metabolism will produce ammonia which is excreted through the gills and is present in the fish’s feces. High levels of ammonia are not healthy for fish, and really high levels can even be deadly. However, there is a certain type of bacteria that feeds on ammonia. This type of bacteria ingests ammonia and excretes nitrite. Unfortunately for your fish, nitrite is even more poisonous than ammonia. Therefore, for successful biological filtration, a second type of bacteria is necessary. This type of bacteria ingests nitrite and excretes nitrate. Nitrate is less poisonous than ammonia and nitrite, but you should keep an eye on nitrate levels in the aquarium and remove nitrate by performing frequent water changes.
You can support beneficial bacteria colonies by providing them with suitable materials to colonize, such as sponges and dental floss media, gravel, sand, plant leaves, etc. When you start a new aquarium, you need to let it go through a process known as cycling. During this process, large colonies of both types of bacteria will establish themselves in the aquarium. You can start the cycling process in a new aquarium by introducing bacteria from an already cycled aquarium, for example by removing some gravel or filter media. You can also buy a solution filled with the right type of bacteria at an aquarium store. If you use materials from an established aquarium, you always run the risk of introducing undesirable organisms along with the beneficial bacteria.
chemical filtration
The most widely used material for chemical filtration is activated carbon. Activated charcoal will bind to a wide range of different compounds and therefore remove them from circulation. It is common for aquarium keepers to use chemical filtration for only shorter periods. When you have completed treating an aquarium disease or parasite, you can, for example, use chemical filtration to remove any remaining medication from the water. The use of activated carbon is quite controversial, and many planted aquarium keepers refrain from using activated carbon for longer periods of time because they suspect it could lead to nutrient depletion.