Skimmer line blocked on in ground pool I think.

Ok, I have a 16x32 inground pool with a hayward DE filter. Filter is running 10-12 psi. I can't vacuum the pool because I'm not getting enough suction from the skimmer line. When I switch the jandy valve from both floor/skimmer or from just floor I start to loose prime within a minute or two. I can see through the pump strainer the flow of water reducing until finally the pump cavitates. I blew the line out with an air compresser with no luck. When I try the moving the jandy valve from on to off trick it sounds as if something is in the line. I took the jandy apart and tried blowing it out with no luck. I then cut the the lines to eliminate the 90 and then blew it out and still no luck. I was able to get decent suction with the jandy valve with the floor drain open a crack to make up for the flow restriction in the skimmer line but once you turn the pool off and on again I can't catch prime that way because I'm assuming whatever is in the line blocks the flow again. There is no mud or sediment coming from the skimmer line so I'm pretty sure the line isn't cracked. I'm beginning to think a powered line snake is my only option. What else could I be missing here? Could the skimmer box be cracked? I'm not losing any water at all in the pool. Could my new super pump be bad? I bought it last year but my son moved the jandy valve when I was dropping the water level to close the pool and the pump went dry for several hours. The pressure coming out of the jets is pretty strong though. Could it be something in my filter isn't right? Please help, I'm going crazy Andy family wants to swim.