I'm looking to replace some filter media (a foam pad and poly/carbon pad. I have the Fluval U-2 that comes with 2 of each in 2 seperate containers) and I found this Seachem Matrix which appears to work wonders. It appears like the little ceramic balls, but smaller, and supposedly helps with aerobic And anaerobic bacteria, that in turns helps with ammonia, nitrites, and nitrates. Plus it has a "LOT" of surface area for these. Was wondering if anyone has used this. Also would it be possible to put this in with some filter floss? Or am I better off with just one or the other? I figure I don't really need chemical filtration (esp. carbon with plants), and would be better off with more biological filtering. I am new to the canister- type of filters so don't know a ton about the different filter media I could add, and why. Or would you recommend something all together different?