Hey all, my FW tank officially finished the cycling process about a week ago.... I think it took like 7 or 8 weeks in total. Well I never changed any of the filter media during that time due to concerns of losing good bacteria. I feel like it should be time to replace it soon though, right? My water is crystal clear, and all levels are at 0 (except nitrates=25 ppm, pH=8). I have 2 filters running in a 10 gallon aquarium. One is a whisper powerfilter that came in a Tetra 10 gal aquarium kit, which I believe only has mechanical and bio filtration. The other is a Duetto 50 made for 10-15 gallon tanks which has all 3 filtration methods, including chemical (activated carbon). The Duetto went in about a week after I started cycling the tank. So how (and when) should I go about replacing the filter media? Suggestions?