Newb question on ppm and adding nutrients daily weekly etc

How does everyone know when to add nutes? say you have ro water at 0ppm..you add ur nutes in a fresh res and bring it to 1100ppm..as the week goes on how do you know when to add more? each week house and garden calls for 275 ml to be added to my res..if the ppm are still around the same each week what is the proper way to add or adjust nutes?

I never really understood so i just been dumping the water and adding new water and nutes each week..I searched the forum but couldnt get any info as every thread has these search terms..lol any tips? thanks

try to keep a constant PPM, except you also want to raise PPM as flowering goes on and they get bigger.

Dump your res several times (3-4) every 2 weeks maybe through harvest too also helps get rid of buildup

so am i doing this right then?

add 275ml to 25 gal res equals 1000ppm

as the ppms dip lower then i add 10ml here and there or whatever it takes to maintain 1000?

so not every week do i have to add 275ml? or am i just trying to maintain the stable ppm of 1000 then dump res every 2 weeks?-

thanks man think i was confused and wasting ashit load of nutes