Ever since I replaced the factory Atman 2500 pump, Ive noticed that I can no longer open the venturi to anything other than off. At off, the highest water level I can achieve is an inch below the start of the funnel. Anything other than off results in a very low water level in the skimmer. The skimmer sits in 10' of water and used to work well at setting 3. Any Suggestions? 
