Low Pressure on a In Ground Pool Sand Filter

Hello support,

I am having an issue with low to no water pressure at all in my filter. Okay here is what I have done so far. 1) I checked the pipes before the motor there is no blockage. 2) I checked the skimmer and it is okay. 3) I checked the motor for leaky seals and for debris in the empeller motor and it is all clear. 4) Checked and re-lubricated the Y valve and it is okay. Now, you will need to know that i use to have a D.E. filter which broke so I replaced it with a 3 yr old Pentair Triton 2 Fiberglass Sand Filter TR60. There is sand in it more than half full. My motor is a Hayward 1HP. I did have to replace the old 2" PVC piping and I tried to match the previous configuration and i used 1.5" PVC instead. The only thing I had to do different was extend the line coming from the motor to the filter going through the middle input. My pool is approx 20,000 Gallons. I hope you can see the photo attached. Here is my theory, 1) My motor is too weak. 2) My piping configuration has caused less pressure from extending it only approx 15". I would appreciate you getting back to me asap.

Thank you!

My sand filter Pentair Triton 2 TR60