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!