Having been experimenting with skimmer designs on my Syl I see only one problem with the belt skimmers. It's only in one part of the tank so unless you can create some surface flow in the direction of the skimmer it's not going to be effective over a large surface area. I built a prototype of the NextGen style oil coalescer and even with pulling off the surface at one end of the tank and dropping the return coolant into the other end of the tank I still have places where the surface movement stalls in the tank. Something is better than nothing but so far I have come across a great solution.