Follow the instructions on the video for intake water level. If you go too low the skimmer will overflow and if you go too high, then you may run the skimmer dry. The reason we put the video together is to show people exactly what the correct location of all the components is. In terms of the noise, the skimmer is still brand new and needs to break in. As the skimmer breaks in and gets coated with bacteria, it will quiet down.
The valve is only used during priming and then never used again. Some people dont even use the valve to prime as kinking the line is faster, easier and just as effective.