I'm going to buy a skimmer from Andy at
Myreef Creations. These skimmers require a high flow pump. However, the tank will be drilled and the equipment will be in the sump. The overflows will be enclosed to prevent escape.
I am not a fan of wet/dry filters. They tend to be nitrate factories. That may not be as huge of an issue with an octopus as it is in a reef, but it is an issue none the less. I prefer to use live sand/live rock and water changes to take care of the biological filtration.
If the octopus can withstand higher flow, I will probaly set up a surge device for the majority of the flow and use a smaller return pump.