Need Pump Recommendation Please

[Daniel P]

Hi, I hope someone can help!

My pool is as follows:

18,000 gallons

23 feet of 1.25" pipe with eight 90's

2.2 sqft Sand filter (44 gpm @ 20GPM/sq ft)

It usually ran around 12 PSI

Old pump was a 1hp Aqua-flo Flowmaster HP, appx 11 years old.

I don't know whether I should get a .75hp pump due to the size of the pipe or a 1hp pump. I also don't understand if/why the return pipe would matter if it's 1.25" vs 1.5" when there is only one jet that i beleive to be .75".

I have also thought of adding another skimmer and another jet with the idea being less resistance would be less strain on the motor and thus draw less power, am I thinking correctly?

I guess the hard part for me is not understanding how to get the feet of head without also knowing the vaccuum and I don't have a working pump right now to check that anyways.

I can get a hayward 1hp single-speed pump for $155, pentair opti-flow 1hp two-speed for $255, or a pentair single-speed .75hp pump for $230.

Thanks in advance!