natural filtration

So I have a 32 gallon biocube and as of now only have a single clown fish, royal gramma and about a dozen snails, I plan on adding corals very soon. I have struggled with dinos in the past and just tested my water and got a .02 reading for phosphates and 0.0 reading for nitrates. Knowing that...

Tank: 140 gallons with 40 gallon sump I plan on a low bio load reef tank with lots of rock and mixed coral. My fish load will be light with reef safe peaceful fish. I don't plan on fish being the main focus but the reef. I would like copepods and bacteria to do most of the work in filtration...