beginners

Hi there I have the bioflow L juwel filter and I currently have the black carbon sponge out as I am medicating my fish but it made me wonder how ofter should I replace that sponge? Does the carbon become inactive in a certain period of time and what really does it do if someone could help me...

Hi all, new to this forum. My fishless cycle has started and it's doing good. Should be ready in about 2 weeks. Thinking about fish now. I had a tank before and restarting the hobby after 5 years. In my mind: 30 cardinal tetras 2 Bolivian Red Ram 6 Boesemani Rainbow 4 Torpedo Barb 4 Corydoras...