Yea that's what Ive been told about the bio balls. I have a rena filstar xP3 full of the ceramic noodles but my nitrates tend to creep up on me if I don't watch it I do water changes every two weeks 25% that keeps the nitrates between 5 and 10 everything else is in good shape. I read on here that people with sumps can keep their nitrates at 0 that's where I want to be.