After a little reading on filtration, I have come to the conclusion that the new bio wheel craze has much merit. I know folks in the UK are less aware of this type of filtration than some members in the States. This might be due to the fact that Marineland seems to be pioneering this type of filtration. I am going to plageurize their work a bit to save me some typing...cause I am lazy..

There are three stages of filtration;

1) Mechanical filtration of water is done by passing the water through a screen, or a thin piece of sponge, or through a floss material, all of which remove pieces of debris from the water

(2) Chemical filtration of water is done by passing the water through small pieces of carbon or zeolite, which is a natural mineral. The carbon or zeolite remove molecules such as ammonia from the water.

(3) Biological filtration of water is done by certain types of bacteria that live on gravel, the surface of glass, ceramic ornaments, plastic plants, bio-balls, floss, or best of all on BIO-Wheels.


These bacteria are often called beneficial bacteria in contrast to the pathogenic or harmful bacteria that cause diseases. The beneficial bacteria in biological filters digest waste in the water by combining the waste that is dissolved in the water with oxygen that is also dissolved in the water.

So your typical filter would contain all three. A type of floss, the carbon media found inside the filter pack, or canister, and the bacteria flourishing on it. Your gravel and other items in you system will also include this bacteria. But due to the water movement through the filter, it will have an enormous amount of this beneficial bacteria.

This bacteria needs oxygen to perform its task of converting Ammonia into nitrites then into nitrates. Here is a couple of equations that quite simply express how this is done.

Using the usual symbols for Ammonia NH3, Oxygen O2, Nitrite NO2¯, and Water H2O, the chemical reaction is written as

NH3 + O2 a NO2¯ + H2O + energy

Or equivalently as a chemical equation like this

4 NH3 + 7 O2 = 4 NO2¯ + 6 H2O + energy

Other kinds of beneficial bacteria combine the nitrite and oxygen, that are both dissolved in the water, to produce nitrate and more energy. Using the usual symbol for nitrate NO3¯, the chemical reaction is written as

NO2¯ + O2 a NO3¯ + energy

Or equivalently as an equation like this

2 NO2¯ + O2 = 2 NO3¯ + energy

This brings to the forefront just how important oxygen is to filtration process. Here is where the bio wheels make their bid for supremacy.

A biowheel is placed into the return flow to the tank. Picture a mill wheel with water cascading over it. This is how a biowheel performs. Its constant turning allows it to have a higher concentration of oxygen available for bacteria to do its job. Studies have shown that a typical tank has 7ppm of disolved O2. Whereas a bio wheel has upwards of 200,000 ppm of O2 available for converting waste!

Run out and get yours now...