Also, filter manufacturers ALWAYS recommend replacing media (of any kind) every month or so because they want to make money - however, as I've seen written in another thread, they don't tell you that you will lose whatever bacteria that are there to maintain a cycle.
Keeping fish that are sensitive to water parameters requires you to test ALL important levels - ammonia, nitrites & nitrates - in order to keep them healthy.
46 gal fw tank with black skirt tetras, neon tetras, spotted corys, cherry barbs, otoclinus, snails & 4 amano shrimp - plastic & live plants
5 gal QT
Remember: Our job is to take care of the water our fish live in