I recently bought a beautiful house in Washington State with a 45,000 or so gallon monster pool. It is fairly old but it good shape with fairly small plumbing (1.5 inch) and a single skimmer feeding a TR-60 Triton sand filter
The motor died right before we moved in and the previous owner spec'ed out a nice Whisperflo but at 1.5hp (and no timer!) so clearly it is sucking a lot more power than necessary.
My previous pool was a combined spa/pool at about 20,000 gallons in Tucson which was being driven by a 2hp pump. That system clearly needed a 2 speed to power the spa jets and so I installed a 1.5hp 2 speed pump and pretty much let it run at low speed silently 24/7 with the SWC.
This system in Washington I see no reason to go 2 speed as there isn't ever a need for high flow (not using the heater, no need for jets and am going to use a electronic robotic cleaner vs suction or pressure side).
Is it pretty simple to just pull the 1.5hp motor, pull the 1.5hp impeller and then just swap in the 0.5hp motor and impeller setup along with new seals?
I price that out at about $225 vs almost $450 for a new 0.5hp Whisperflo, though that would also allow me to sell my almost new 1.5hp to someone who thought they needed that much horsepower.