Aquariums are a stunning addition to the home, whether they’re coldwater or tropical.  No matter what type of aquarium you have you’ll need a filter to keep it clean.  But how do you know which is the right one for you?  We’ve tried to make things a little bit easier by putting together this overview on the different types of aquarium filters. Read on for more.

Canister Filters

Canister filters sit completely outside the aquarium and have excellent filtering capacities. They are generally hidden inside the aquarium stand or in a special cabinet.  Water is filtered by being siphoned down into the canister where it then passes through the filter media.  Once completely cleaned, the water is pumped back up into the aquarium.

Internal Filters

An internal filter is one that sits wholly inside the aquarium!  Water is drawn through one end of the filter and is passed through the filter media. Once cleaned, the water is returned back into the aquarium. 

Hang On Filters

These filters hang on the side of your aquarium, on the inside.  Water comes up through the bottom of the filter, through the filter media, and then is returned to the aquarium once it is clean.  This is a common type of filter, and it is both easy to find and easy to use.

Air Driven Filters

Air driven filters are powered by air, which is supplied by an air pump.  What happens is that a vacuum is created which causes water to be drawn through the filter media, which is commonly filter wool and charcoal.

Under Gravel Filters

An under gravel filter is, as you might have guessed, a filter that sits underneath the gravel inside your aquarium.  They are operated by an air pump or a power head, which creates a vacuum, drawing water and debris through the gravel, up through the pipes and back into the aquarium.  In this way, the actual gravel itself becomes a part of the filtration process as beneficial bacteria colonise the gravel and help to remove impurities from the water.

Types of Filtration

No matter what type of filter you have, it will probably fall into one of three main types – mechanical, biological, or adsorptive/chemical.  Mechanical filtration is where particles are physically removed from the water.  Biological filtration helps to break down any waste products inside the aquarium, and it works by using beneficial bacteria.  Adsorptive/chemical filtration is quite selective and will actually remove certain substances from the water. An excellent example is activated carbon which is used to remove toxins, medications, dyes and so on.