If your using it in soil, do not ph it too low or it will fuck up your medium and lower your ph to bad lockout levels.. I have been using sensi bloom for a couple of years and i agree with him telling you not to go by their calculator cause its wrong, I don't know what planet whoever thought that cal up but if you go by it your shit will get all fucked up.. Best advice when using AN's is get a ec or ppm meter