my source of water is city water and yes Ro , i allready mesure the Ph several days , and its arround 5.5 ,5.4 , 5.7 , so its good , and i saw many hydro movies , but i have not seen in anyone exactly how to make ppm,i know that when the plants grow , you need to high the ppm , its not save for me to buy ppm s meter,the sistem was buy directly from holand(nutriculture aeroponic amazon 16 plants),here the c0psz are straight eyes.so i want to find another solution for this measures and start to grow , i know hydro is need a lot of atention,and i will pay attention, anyway i saw different thinks in different hydro movie , and another aspect that im missing , is how much water is necesary for example 100 liters or 27 gallon , cause nobody says if the water tank will empty half or will empty just a little,i think the bigger plants the lower water lever from tank,and after full the tank with necesary water shaked with the mix , im wrong? , i saw only when they drop the nutrients solution allready shaked with water carrefull and read on the ppm screen meter. if i start ..just to say (and what i think) first day when i put the plants in sistem and start the proces with one coup of nutrients , and in time when the plants grow after a week i will put 2 coups , in week 3 will be 3 coups of nutrients. this will not work ?