I am planning on using only a protein skimmer on the 30g tall octo tank that I'm currently setting up. Reason being, as a sps reef-keeper, I/we never use mechanical filtration because it tends to actually increase the nitrates (all the gunk in the filter ends up breaking-down and going back in the tank). Since low nitrates seem to be quite important with octos, what do you think? The skimmer is suitable for tanks up to 90g. I'm just not used to keeping animals that produce so much waste. What are your thoughts? By the way, I'm also considering the Cyclone BakPak 2, and the BakPak 2R. The 2R is made for a reef and does not have the biological filtration section. Which would be most appropriate for an octo tank? Thanks.