I run my pump in the wee hours of the morning. I just went out to do my chems today and turned on the pump only to hear it run but push no water. The attached picture is while it was running. At the very end of the 3 minute priming cycle it finally started pulling water. I had turned the lever so it pulled from the skimmers instead of the drains and skimmers. I am unsure if this had anything to do with it. Any ideas as to why the water kepps being replaced with air between pump runs???