Aquarium Filtration for Beginner

Filter is the most important equipment in an aquarium and this is what you must know before getting into fish keeping. 

There are many different types of filtration systems in the market and for a beginner it can be confusing. There's a hang-on where the filter hangs on the outside of the aquarium, internal where the filter is submerged in the filter and there’s canister where the filter is in a canister sitting below the aquarium connected with 2 hoses. And there are many many more. They all have their advantages over each other. This is because they are made to be used based on different criteria such as design of the aquarium, type of fishes and budget. But they all do the same thing. To house the filter media. 

A filter system is nothing without its media as the one that is doing the filtering is the media. Therefore without the knowledge of how the filter media works, you will not be able to bring out the full potential of your filter system. 

There are mainly 3 groups of filtration media in aquariums; mechanical, biological and chemical. 

Mechanical Filtration

Mechanical filtration refers to the type of filter that mechanically removes / blocks solid debris from water. Sponges are mostly used in this type of filtering although some other materials are available. Depending on the type of filter system, they are sometimes placed in the first or at both the first and last stage of filtration. When placed in both the first and last stage, the first stage is meant as a pre filter to filter out larger debris before entering the rest of the filter system. A less dense type of polyurethane sponge is usually used as a pre filter. Usually it is what we call a bio sponge where this type of sponge, if only being clean with aquarium water will house beneficial nitrification bacteria and act as both mechanical and biological filter at the same time. The main mechanical filter that is usually made out of wool, usually in white. While there are several types of wool sponge available, they all have the same function and result. The only difference is the more expensive stronger wool sponge filter will withstand more washes and reuse then cheaper one. There are also some that aren’t meant to be reused and are way cheaper than the reusable one. For those that are lazy to clean their filter, we highly recommend the non reuse type. 

Biological Filtration

While all 3 times of filtration are important, biological filtration is the more crucial one. This is because biological filters are usually used to filter the highly toxic ammonia that is generated from decay organic material. This includes fish food, feces, dead fish and so on. High ammonia levels will also cause the water to be cloudy and can easily kill fishes. While there are other methods to remove ammonia from aquariums, biological filtration is the most feasible one. As the name suggests, biological filters use biological methods to filter ammonia where we grow nitrification bacteria in our filter. This bacteria will convert the toxic ammonia to less toxic nitrate. How less toxic? While a mere 0.05mg/l of free ammonia is considered dangerous, nitrate level that is less than 80mg/l is still considered ok for most fishes. Nitrate is also colorless therefore even when you have a high amount of nitrate in your aquarium the water will still look clear. 

Stones that are made out of porous material are usually used to breed this type of bacteria in the filter. Chemicals that will kick start the bacteria in a week will be applied to a new aquarium prior to adding fishes. Depending on the brand, usually it would take around 1-2 weeks to cultivate mature bacteria to filter ammonia.

Chemical Filtration

In this filtration, a chemical reaction is used to filter the water. Commonly used are activated carbons. Carbons are highly porous and able to absorb variable impurity in water. In aquariums, carbon is used to remove yellow tint color in water, fish odor as well as some other minerals and organics impurity. It is basically a Swiss army knife. Although it can absorb variable impurity, it does not absorb thoroughly when it comes to minerals and organic impurity. But it is nonetheless the most popular chemical filtration media. Activated carbon comes in a wide range of prices. The more expensive they are, the more effective and longer lasting the carbon is as the lower quality carbon usually contains high levels of impurity and phosphate. 

There are some other chemical filtration media which are designed to absorb certain types of impurity only. Seachem Purigen is designed to effectively remove all organic impurity and color tint in water which make it more effective in providing a crystal clear water then carbon. But it doesn’t absorb minerals or chemical impurities. There are also some chemical filtrations that are designed to absorb certain types of impurity only such as phosphate remover. Removing phosphate will slow the growth of algae. All chemical filtration is meant to be replaced once exhausted except for certain media which can be reused for several times before needing to be replaced such as Seachem Purigen and Seachem Cuprisorb. 

Chemical filtration is usually placed in a net and should always be placed after mechanical filtration.