So you have a diverter plate in the skimmer. You man drain pulls through the skimmer the teardrop shaped cover on the bottom of the diverter determines how much flow comes from the main drain and how much from the skimmer the way you have it in the picture you are getting as much flow from the skimmer as you can with the plate in place, I would leave it just like in the picture, you want a lot of flow from the skimmer. In my opinion flow from the main drain is less important than skimming others may disagree. If you were to close the teardrop completely than all the flow would come from the main drain assuming of course you have the lower valve set to either pool or both pool and spa.