Hi, I have 65 gallon DT with a 20 high diy sump that is feed by a Blue Ocean OF 600 Overflow Box Continuous Siphon Aquarium Hang On 125G. I can’t seem to be able to skim off the surface film on the top of the water. My overflow box has about 1/2 inch difference between water surface outside and inside the box itself. I have one of my power heads pointed up at the surface on the other side of the tank. My skimmer is located in the sump Reef Octo Any ideas on how to get the overflow box to skimmer the surface?