I have an older half horse Jacuzzi brand jet pump(model#5JHACOH70) and a 40 gal. pressure tank that a freind gave me. I am having trouble getting it to pump volume and pressure from the intake line. I hooked it up to a 5 gal bucket and it seems to work all right, although it wouldn't pump past 35 psi. When I hook it up to the main line (1" plastic, with gravity bringing the water to within 4 or 5 feet of pump level)and prime it the most pressure I can get is 15 to 20 psi. When I open the valve at the pressure tank there is only a small amount of water mixed with air, and if I open the valve all the way the flow and pressure completely stop. Can you give me any advice? Also, how many feet will this type of pump lift--Am I trying to lift the water too far?