I have been a pool owner for many years and I'm at a loss as to what to try next to solve my pool issues. I have a 17'X35' inground pool that is 12 years old. I have been battling low pump pressure since last year. I have replaced the pump with a brand new 1.25 hp Pentair pump, changed the sand in the Triton II filter system. All the parts in the sand tank are in good condition with no broke parts. The pump only out puts 6psi, with low out put on the 4 jets, the skimmer box has very little suction, vacuuming is impossible. I know I don't have a blockage in the skimmer line, we ran a snake through the line to eliminate this. When the pumps running the secondary basket fills up with no air at the lid. There are no bubbles coming out at the return jets and the pool is not losing water. I have spoken with many local pool technicians and they weren't able to help. I'd appreciate any advice on what to try next.