I don't know about ppm but they sell ph test strips...just dip them in the water and they change color then compare to color chart that comes with the strips
I currently use an Oakton Eco ph pen. Digital display, water-proof, works great so far. Cost me $50-$60. Be sure to get some calibration solution and backup batteries.
There are also digital pens that are ph/ppm combo.
Good luck!