I use filter socks to remove small particles in the water. Skimmer pulls out dissolved organic matters like protein which tend to have a yellow color. Skimmer is also good for air exchange.
Take the skimmer off line and ats will grow a lot more, a lot faster.
Take the ats off line and skimmer pulls just as much.
Take the sock off and you’ll enjoy your tank a lot more. Maybe have to clean your sump one or two times a year more often. But way better than changing/cleaning socks twice a week.
I Also run an undersized Uv for clarity, and don’t run carbon, anymore.