Newbie Nute help

If my ph is dropping, do I just add little water then check ph/ppm level, and if im reading a constant ppm drop, do i just pre-mix all the nute's together then drop it in rez and keep adding all the nutes till i get it to the ppm i desire.
Thank you for any advice <---- New grower xDD

Keep on adding nutrients to your res. until you get the desired ppm. I take some out of the res then add nutes to that then put it back into res.
Keep adjusting ph likewise
If I've understood what you're asking?...

i add water to drop PPM as needed,add nutes to raise ppm,

but you might need ph up/down to raise or lower ph,as im not sure if adding just water will drop PH,
if thats what your asking about PH