Most skimmer can run at different depths and from system to system either raising or lowing your skimmer in your sump could easily result in better performance and skimate production. Depending on the depth of a skimmer the characteristics of how air is pulled into the skimmer pumps venturi changes dramatically.
Adjustable Solid Platform to raise protein skimmers in 3" / 3.8" / 4.5" increments.
SST 1: 11"x7.5"
SST 2: 13"x9"
SST 3: 17.7"x11"
Simply select the stand with a larger footprint than your skimmer, and that will fit into your sump
Adjustable Protein Skimmer Stand - Reef Octopus
Having the ability to adjust the height that your skimmer sits in the water can change how the skimmer pulls air and water into its reaction chamber. Most skimmer will have a sweet spot, that on your particular tank will run best. By having an adjustable skimmer stand you can fine tune the height of your skimmer to get the best results possible on your particular system.