The most frequently removed substances are, amino acids, organic dyes, fatty acids, fats, enzymes, vitamins and many inorganic compounds like phosphorous and iodine. T he main draw back to this piece of equipment is that it cannot differentiate between desirable and undesirable substances, thus removing most matter from the water. The most important components of the water column that gets removed are the micro algae, and micro fauna that forms the plankton and serves as source of food many of our organisms that we are trying to maintain. This trickling of the water through the filter media exposes the water to a large amount of air, aiding in the removal of CO2. The removal of CO2 from the water aids in keeping the PH high and the large surface area of the filter media houses a large colony of bacteria.
Nitrites are as toxic as ammonia themselves.
O zone is the most powerful oxidant readily available for water treatment. It is used by injecting it into the water. This is normally done in a chamber commonly known as an ozone reactor, but most commonly it is injected into a protein skimmer directly. Before the treated water is returned to the aquarium it must be passed through an ozone destruction device, such as a UV light of activated charcoal. The water treated has to have all ozone removed from it.