Forget usiing that valve for now..Just rasie your pump up to within 1 1/2" of the surface contrary to what your enclosed directions state, and make sure your outflow tube is at or above water leve in tank...turn red adjustment knob fully closed, make sure your air line is attached and the end of it is out of the water and not restricted, make sure rthe outflow bleeder hole is not obstructed, turn on skimmer adjust red knob for a bubble height about 1" or so above red retaining ring that secures collection cup. Once its running a bit, adjust red knob to get bubbles in reaction chamber to within 1/2" of bottom of the funnel portion of collection cup. Those ksimmers work fine if proper instructions were included. New instructions are available on their website, but best thing is chuck that big bubble diffuser box like I stated earlier and use a filter sleeve of foam in its palce but make sure outflow tube is at or above tanks highest water level