I don’t go by ppm, I usually use EC as my measurement but during veg I’ll let it go from 1.0-1.5 and during flower I’ll slowly bump it up to 2.3 if I’m growing in soil.
the ppm measurement is half of that for the US conversation so -
Veg = 500-750ppm
flower = 750-1150ppm
but make sure you know what your pen uses for measurement there’s 2 types, ones the US form of measurement and the other is the European form.