Carbon Filter media for TetraTec EX range and other external filters. Keeps aquarium water crystal clear. – Reliably removes organic waste. – Reduces odours and water discolouration. – Keeps water looking fresh. – Phosphate free and pH neutral – no adverse affect on water chemistry. – Takes unwanted chemicals out of aquarium water (e.g. pesticides medicines etc). Rinse well in lukewarm water prior to use. Replace every 2 – 4 weeks to maintain efficient filtration of aquarium water. Remove carbon if you need to medicate your aquarium and replace once treatment is complete. Suitable for all external filters.