There are many different types of aquarium filters. The two main categories I would divide them into are internal and external.

Rather than go into the differences I'm going to flaunt conventional wisdom and say that any filter that exposes the aquarist to flooding is off the list as far as I'm concerned.

Then I will go one further and say that I prefer natural filtration which reduces the possibilities to very few.

Live rock, macroalgae, and water.

Let me begin with water.

The more water in an aquarium relative to what is living and inhabiting the tank the better the capacity of the aquarium to absorb the biological wastes generated by the inhabitants. The ideal set-ups are often found at public aquariums where the source of water is sometimes nature – such as the ocean for a marine aquarium or a lake for a freshwater aquarium.

To be continued ….