I just want to put out there that this website is full of info that has helped me set up my 65 octi tank. I have a question that I could not locate a foward enough answer. If I am doing 10-15 percent water change every week do I really need a skimmer? I am using 2 canister filter 1- Rena X3 and 1- Cascade 1200. The Cascade is nothing but carbon in 3 slots and poly filter in 1. The Rena is carbon, poly filter, ceramic rings, and water polisher pillow. The substrate is sand about 2 1/2" deep with about 15 pounds of live rock. Still looking for the perfect den. I have not purchased a octi yet. Really looking foward to that day.