I have a Fluval 404 and I love it. The best thing about this canister filter is that you can customize it anyway you want. There are 4 chambers, each of them has two compartments. Before and after water goes in and out, there is a foam filter. Then the water goes through chambers. My chambers have pre-filter (2nd pass of water to collect more debris), carbon, and bio-max (for bacteria cultivation). These combinations have kept all my levels at 0, but since I have the bio-max and live rock, my nitrates are 0-10ppm which I think is healthy. But remember, the live rock is a must though, because the rock also helps to keep the nitrates low.