I am putting together my first multi tank system. Live rock, Fish, and easier corals. 50 Gal Breeder Display tank 30 breeder 33xl 350 gal black plastic water tub. Here is a basic design for my set up. The 33xl will sit above and slightly behind the main tank and the 30 breeder will sit in cement block that will actually be inside of the plastic tub. What type of additional filtration would be helpful in bottom plastic tub sump. I was thinking a filter sock but beyond that I could use some insight. Do I really need a protein skimmer if I have excessive biological filtration.