“Immediate and reliable absorption of toxic substances and water discolorations, such as yellowing. The water will become crystal clear again. sera super carbon does not affect the pH value and is completely free of nitrates and phosphates.The carbon content of the filter should be increased after each treatment for a short period of time. Do not add carbon, or remove any carbon you may be using, before any treatment with medication. Otherwise, the active ingredients of the medication will be absorbed directly by the carbon. sera super filter carbon remains active for 6 weeks due to its enormous surface area. For use in filters for freshwater and marine aquariums.”