Help selecting replacement Pump

[mizzouguy]

Sorry, the pool has 1 1/2 piping!

[Poconos]

Lower flow through any filter means better filtration. At higher flows and pressures you tend to ram dirt right through and with sand it can lead to channeling where the water cuts channels in the sand bed and thus no filtering at all. Someone else that has a better feel for sizing will probably chime in.
Al