GMSgrowsanswered grow question 3 years ago Yes it is to feed your plants from the top and know what's at the roots as well. For coco a ppm of 800, 1.6 ec is a good range for photo period plants. 600ppm 1.2 ec is good level for autos. If you check your runoff waters ph and ec level and their going way past that level, you know lockout is just around the corner so you run some plain water through to lower it back to acceptable levels. If EC is getting low you know to increase a little same with ph. Always stay in range for trouble free grows. Cheers