The Ph and PPM made all the difference in the world for my growth. Mind you I am growing Drip Hydro method. As the plants eat the food the Ph rises and if reaches toxic level the plant will stress out and in return lose productivity. Also the plant will drink just the water some days so then the PPM gets to high and again the solution becomes toxic. I started my clones at 400 PPM and after the first weeks started to increase the PPM.
Now maintain them at 1400PM and check the ph and PPM three times a day. If PPM gets to high add water then adjust Ph. Once a week empty the reservoir and flush with just water fro 24 hr then add the food. Here is a pic after switch to flowering and week 4.