I'm considering replacing both my main circulation pump (1 hp Sta-Rite DuraGlas) and booster pump (3/4 hp, A.O. Smith motor, driving a Polaris 380). Measurements on existing system show a flowrate of 53 gpm with a Total Dynamic Head of 42.4 ft. I have no attached spa, water features. Just two 1-1/2" return lines and a return to drive the Polaris.
I believe the original circ pump was just a 3/4 hp and, for reasons long since forgotten, I replaced it with the larger 1 hp pump. Probably in response to the Pool Store's "bigger is better" mantra. The 3/4 hp booster pump seems like overkill as I need to add a return line flow restriction (pinched valve downstream from pump discharge) to keep from overdriving the Polaris.
So, I'm wondering if my pocketbook would benefit from smaller pumps (run longer, if necessary) in one, or both, cases. Would I benefit from a 2-speed on the main circulation pump and also going down to a 1/2 hp booster pump for the Polaris?
What would be the smallest size I could get away with for the main pump?
32,000 gal. IG plaster (circa 1967); 24" dia sand filter; Jandy Lite 2 (250,000 BTU)
1 hp circ. pump (Single speed, 53 gpm); 3/4 hp booster pump (Polaris 380)
1 bottom drain, 1 skimmer, 2 return lines, 1-1/2" PVC plumbing