The 160 works best in 8 to 10 inches of water, so you lucked out there.
Put it in the skimmer chamber and turn it all the way open and let it run. You may not get any bubbles at all, depending on your bioload. The bubbles will start out large and 'POP" quickly. After the skimmer starts to break in, the bubbles will look more like foam and start pulling skimmate from the system. This may take weeks. Every couple days, turn the pipe closed just a hair, and you will start seeing a difference in the performance