I have a 6 year old Whisperflo 1.5hp pump. Today I noticed the pump was on and running (sounded quiet and normal) but there was no flow. Small amount of water in the pump basket. Removed cover and checked impeller, it rotates freely. Nothing looks out of the ordinary with the pump. Pool has been functioning fine all summer, plenty of pressure in my fountains and returns. Multi-valve lid and gasket are fairly new. Cartridge filters and salt cell are only 5 months old. Have not had any flow issues since I opened the pool 6 years ago. Main drains and skimmer basket are clear as far as I can tell. Water level is a few inches high from recent rain.
Where do I start?