Why preform. Physical skimmer hieght adjustments?

[ddc0715]

adjusting water height controls the water column in the skimmer, that im clear on. Turn the knob for up or down....so what does adjusting the physical heights of the skimmer itself do.? or improve. My skimmer says 7-9" im at nine. What differences should i see if i go to say 7"?

 

[sbash]

This question reminds me of this scene:

Quite simply it is just another way to tune the skimmer. Getting a nice dry skimmate is the goal (by some), so having the more ability to tune and adjust the flow into the cup is a good thing. A dry skimmate should mean the skimmer is being as efficient as possible.

I would set all settings in the middle, then adjust the water level in the skimmer chamber to give me an average output. Then tune the skimmer (using the knob and height adjustment) to get a more refined output into the cup.