Hi bro , I check ppm/ec and ph daily , I fill with ph tap water (mine is 0.4 EC ) sometimes twice a day , to maintain , I add between 1-5 ml of nutrient base ( A+B) , I ONLY ADD sugar and boost when I change the whole reservoir , to fresh solution , I change solution every 10 days in flower 🌺,less in veg ( if ever ) - I flush for two weeks with pure RO (0) water , if you let the ppm rise and fall it's no big deal as long as its not excessive , DWC really doesn't need much at all , I am trying a 3 week flush as an experiment , but 1 week seems ok .question do you want sugar in your buds or thc?