good information guys -
i just asked marinemom on where this "common knowledge" on the effectiveness of carbon was documented? I dont think its correct to just state something is fact with out giving some background or documentation -
Activated Carbon is used for Chemical Filtration of water in many applications and filter life is never stated at 2 days. The water in my tank stays crystal clear when i use carbon - a bit hazy when i dont. I have only seen articles stated that carbon is not great in planted tanks since it takes out some trace elements that the plants need.
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Chemical Filtration
Chemical filtration is the adsorption of dissolved organic impurities from the water. Activated carbon is used for this purpose. You can utilize carbon by putting it in your outside power filter or inside box filter. Activated carbon can remove discolorations, odors, and other impurities from the water. A small amount of a quality grade carbon in the filter can keep the water looking sparkling clear.
Carbon becomes saturated and is no longer effective after a period of time. For the average aquarium we recommend that the carbon be changed once a month. Carbon can be replaced more frequently if the water is cloudy or an odor is present.
Absorption Potential of Various Substances by Activated Carbon
High to very good
Arsenic, bleach, chloramine, chlorine, chromium, colors, dyes, gold, insecticide, odors, monochloramine, tin
Good to Moderate
Acetic acid, cobalt, detergent, hydrogen sulfide, mercury, ozone, potassium, silver, soap, solvents, vinegar
Fair
Copper, iron (not chelated), lead nickel, titanium, vanadium
Low to None
Alkalinity, ammonia, barium, carbon dioxide, hardness, copper, manganese, nitrates, selenium, molybdenum, zinc.