OK. I looked at your equipment specs. Assuming:
+ 15k gal plaster pool
+ 1.5" ID S-40 PVC piping
+ Pentair 100sft cartridge filter
I'd recommend a
+ Pentair 340042 SuperFlo 1hp 2spd Pool Pump 230 volt OR
+ Hayward SP2607X102S 1hp 2spd Super Pump 230 vold
AND a spare
+ Unicel C-7699 Replacement Filter Cartridge
(if you don't have a spare)
I've liked the Hayward Super Pump for a long time in this sort of application. But the SuperFlo is designed specifically to compete, and is cheaper on Amazon. Both are 230 volt pumps with a toggle switch, so you do not have install complicated 2 speed pump wiring (which most pool guys, and many electricians can't do!). However, if you don't have a timer, installing one will pay for itself in a year or so, even with a 2 speed pump:
+ Intermatic T104 240-Volt DPST 24hr mechanical switch

Once you have it all in:
1. Operate on low speed 8 - 24 hours per day
2. Use high speed when vacuuming, etc.
3. Rotate cartridges in and out, keeping a fairly clean cartridge in place.
Several important points:
+ Both pumps are 240V, not 120V. Make sure you're ready for that.
+ The timer is also a 240V timer.
+ The timer will NOT toggle Hi/Lo, but only On/Off
+ YOU toggle Hi/Lo manually.
+ Dirty cartridges are damaged by large pumps FORCING water through them
+ Clean-ish cartridges work well with low speed pumps; dirty ones, not so much.
+ You should replace the pressure gauge, if is not working.
=====> Winters SS filled gage w/brass internals, 0-60 psi 2.5" Dial +/-1.5% Accuracy, 1/4" NPT bottom mount
+ If your existing cartridge is shot, you should get TWO need cartridges.
+ Unicel cartridges are OEM quality; discount Chinese cartridges are NOT
.