It takes a couple weeks to get broken in....then it will start producing some skimmate. I ended up putting a sponge over the output tube to stop the bubbles. Most of the microbubbles went away after the 2-3 week break in period, but I still had pretty significant bubbles coming out after that....I just used an aquaclear filter media sponge and cut a slit in it to fit the output tube.
And I agree....the instructions are terrible! I could not get mine to siphon when I first got it....stressed me out!