A fish tank filter functions when water is sucked into its inlet, forced through the filter media and is then pumped back into the tank.  When the water flows through the filter media, it goes through one or more filtration methods namely mechanical, biological and chemical.  This ensures that when the water is pumped back into the tank it is pure enough for the fish to survive and breed healthily.

But these days, fish breeders are presented with a host of different filter media that it can be very overwelming to a beginner.  Even though these different filter media were made with one purpose in mind, that is to filter the water, they all have different functions that they provide.  Here are some of the most common filter media types and the functions they provide to your fish tank.

Mechanical Filter Media

These include sponge, foam blocks, floss, fibers and scour pads.  Mechanical filters are the most basic form of filtration but they are a crucial method.  These filter media are created for one main function, to filter out large waste and debris from the aquarium.  These media are porous, allowing water to flow through easily.  However their pores are small enough to trap larger matter such as fish waste, excess food and particles.  The size of these pores determine how effective the filtration will be.  Smaller pores provide better filtration.  However, the downside of this, which is also a downside of all Mechanical Filters, is that if the pores are too small, they will easily clog up and would need more frequent cleaning for it to perform good filtration.  The major benefit of Mechanical Filter Media is that they do not need to be changed too often and the only time you would need to think of changing them is if they are considerably worn out.

Biological Filter Media

Some examples of biological filter media are bio-balls, ceramic rings and canister media.  Biological filter media works on the principle of providing a suitable surface for beneficial bacteria colonies to grow.    Beneficial bacteria reduces waste that would otherwise be toxic to the fish into substances that are less dangerous.  It takes time for bacterial colonies to grow so never change a biological filter media because you would only be discharding those useful colonies that took so hard to cultivate.  Not only is this a waste of time but it would greatly reduce the biological filtration in your aquarium.  You should also not wash biological filter media in tap water because the chlorine in tap water will kill off the colonies of bacteria.  Instead, you should wash it in some of the water that is siphoned from your existing fish tank.

Chemical Filter Media

Examples of these are carbon pouches, chemical gels and phosphate pads.  Chemical filter media is generally more expensive and not really necessary except in tanks where you have performed some kind of chemical treatment such as quarantine tanks for sick fish.  Their basic function is to remove chemical residue from the water which is not really at critical levels in a normal fish tank.  Also, used wrongly they can alter the chemical and pH balance of the fish tank and may even be detrimental to the health of the fish.

That is some of the most common types of aquarium filter media which you could buy today. For more information on the various aquarium filter media, visit Fish Tank Filters at http://fish-tank-filters.org today.