When using a single type of filter media such as Lava Chips or Ceramic Rings or Bio Rio, the only way to obtain a larger surface area for bacterial colonization is to increase the quantity of filter media. The external canister filter, which is the main type of filtration system used for Nature Aquarium, consists of a canister filled with filter media (i.e., filter part) and a pump for water circulation.

In anticipation for a subsequent increase in the amount of filtration media, it is better to have a large capacity canister from the beginning, and accordingly the flow capacity of the pump also needs to be increased to withstand the load of the filter media. As can be observed from this, the external filter that is to be used for large aquariums needs to be equipped with the larger size of both the canister and pump. However, it is in fact impossible to make the canister as big as desired due to the limited size of the installation site (i.e., cabinet) and also the restriction in height.

In the case where the filter can be installed at the side or back of the cabinet, it is possible to install a larger filter such as 1500LPH & above . The benefits of using the larger canister size is not merely that it can contain an increased amount of filter media, but also that it provides a longer path through which water flows at an adequate rate. As we all know, the tank water flows through the filter media within the canister.

If there is a longer flow path, more contaminants in the water will be broken down by bacteria on the filter media and as a result, more purified water is obtained. What we have to remember in this regard is that there is a limitation on the canister size due to the structure of the external filter which requires a certain difference in height between the water surface and the pump for it to operate.