I realize this is a common question (after several google searches) but I haven't found a solid answer yet. How do you set up a skimmer? I let it run, change depth (I can't let the water in the sump get too low because the pump will suck air, and i can't raise the skimmer any more or it won't clear, i have tried running the level at the skimmer between 8 and 12 inches), even added an air valve and I simply can not get the skimmer to not overflow within a few minutes. Its become very frustrating and really is the biggest pain for me in the hobby thus far. Whats the secret?