Well it's hydroponics anyway so if there is any problem they are easy and quick to fix. Try it at the set number around 1200 ppm then add your other nutrients. If it turns out to be too much then just add more Ph adjusted water and that will drop the PPM real quick. Add about a gallon at a time until you know. Itâ??s easy to add more but it's a bitch to play the Ph up & down game, likewise the nutrient number game. Your plants will tell you if they are happy or not just look for the fan leaves forming a "V" for victory. That means they are happy. Once you stop feeding "N" the fan leaves will show sign of stress on the leaves. They could show spots and yellow but that's normal. The plant is using up stored energy in the leaves so it's ok if they even die off.