Sump water level for Diablo 160 XS

I have this Skimmer running on a 135. Its only been running for 5 days. The manual says sump depth should be 6-10 inches, but water should not be above outlet pipe. I currently have my sump level at 7 inches, but this puts the outlet pipe below the water level. Should I cut the outlet pipe to stay above water level or is there a different way? Also right now I just have the outlet pipe angled so that its above the water line.