I replaced the single speed motor on my Sta-Rite Dura-Glas P2RA5E-118L pump with a  Century B2982 1HP, 1.65SF, Two Speed Motor and re-used the Pentair C105-138PEB impeller and the Pentair C1-200PA diffuser from the single speed motor.

Would a Pentair C105-137PDBA impeller for 1-1/2 HP be a better choice?

I filter the pool water using the low speed and pump water through my 7 solar roof panels using high speed.

Thank you,